Honestly I'd rather a battery that's super reliable and NOT using any lithium ion inside it in my home.
As it doesn't need to move, it can sit there in an unused space and be really heavy. Lead Acid Batteries are a very good fit here (traditionally used as the 12V battery in cars).
In Australia you can buy a 12V 42AH (amp-hour) battery for ~$150AUD or $100USD.
20 of these will give you 10kWh @ 240VDC.
Couple this with a 6kW solar system and you'd be almost entirely free from grid electricity, especially in summer.
You can individually test out the batteries and swap out bad ones. The batteries themselves typically last >5years in a car and I imagine much longer at home where they aren't exposed to high engine temps and large continuous current discharges (engine cranking on start up).
You might want to check LiFePO4 battery chemistry. Heavier than Li-Ion, but longevity is better, as well as safety. I have been told that you can hammer a nail through a cell and nothing spectacular happens.
(One) trouble with lead acid is that deep discharges are really bad for the longevity of the battery. So you can use only a small fraction of the capacity if you want to run regular cycles form it.
LiFePO4 is great - especially as an addition to solar systems currently using lead acid.
If you add a couple of LiFePO4 batteries before your lead acid (you should do some basic math where you have enough LiFePO4 to last about 1-2 days, depending on your location, without having to hit the lead) using a DC-DC charger (which does reduce efficiency - but that's ok) you increase the size of your pack, really help pull ALL the power out of your solar that you can, add a very safe battery (LiFePO4 is really safe compared to traditional lithium), and best of all, you really, really, really extend the lifespan of your lead.
I mean like, you probably will never be able to kill your lead doing this, for multiple reasons: primarily, you're just not using it that much, but you're also really keeping it topped off when you do use it.
The key is that lead acid isn't great at sucking up charge when it is 80-100% charged. So it is really hard to "catch up" charge with solar, even if you have a ton of it. Solar is not going to put out more than it draws. So if your batteries will only accept some X of AMPs to charge, that is all you're getting (well, you can use extra power for other stuff when this is happening, if you're set up that way, like powering appliances, so you can get some benefit still).
However, with LiFePO4 - that bad boy will take all the power you can throw at it (well, not technically, but for the purposes of a solar array, sure) and top off really quick. Then, when the sun is down, it charges your lead.
I think the benefits of this is more important for smaller arrays with fewer lead acid batteries, and where the LiFePO4 battery will be a single $500 100ah battery (rather than 10 of those), but I imagine even in large large setups this could really help.
LiFePO4 is amazing but I think the cheapest you can go right now by buying used server rack equipment is like $250 for $100ah? So 2.5x or more the price of lead, and you're comparing a used battery vs a new battery (and with the lead, $100 will probably get you a reputable battery, not some no-name used LiFePO4 battery).
This is nice idea that I watched some video about it few months ago, but will prowse (do you know him?) didn't like the idea as he prefers all lithium (he thinks it's cheap enough), I'm living in 3rd world country with a LOT of power outages (basically no power), I have a solar array with tubular lead acid but I'm soon switching to LiFePo4 when my package come from China, I feel tempted to implement your idea instead of selling my acid batteries. Do you think I can use MPPT controller instead of DC-to-DC charger? Technically it works like that I think
Yeah he knows way more than I do - and I agree that all lithium is probably the best way to go if you can afford it and are starting from scratch.
In my case, similar to yours, I had a ton of lead already - replacing all of it would have cost a lot of money, and would have been wasteful as the lead was only a few years old.
> Do you think I can use MPPT controller instead of DC-to-DC charger?
Only two issues I can think of, but definitely do your own research: 1) unsure if you can set up something for the MPPT to cut off charge if your source battery drops below a certain voltage, which you can do with at least some DC-DC chargers, and 2) it is common for MPPT charge controllers to lack the capability to boost voltage, just convert it lower.
#2 can be mitigated by setting up your lithium bank to provide higher current, which has its own dangers, but has added benefits as well such as requiring smaller diameter wire.
#1 is a serious concern and can also give you safety problems outside of maybe killing your lithium - so please make sure you're being safe and doing your research. maybe ask in diysolarforum.com ? I haven't posted there myself but have gotten great info from threads there.
Thanks for the advice I will consider posting a question on the forum when the package arrive. Will's opinion was a comment on this video btw, I can see now it's not totally negative though [1]
For the problem #1 I think the BMS can solve the issue as I already ordered a JBD BMS so it can cut off whenever it reaches the critical voltage.
For #2 you're right I think I should check, my MPPT is good one (Epever) but not sure it could lift the voltage properly from such a narrow difference, unless maybe I use higher voltage (such as 48) than my pack 's voltage (24v) so it will be guaranteed to only reduce the voltage to the lead acid levels.
Thanks so much!
Yes - I have watched this video. Emily & Clark have a different setup, as he uses a different device (or even, no device) to connect the two different banks (lithium and lead acid).
I didn't see Will's comment tho, thank you for sending that, very thought provoking! The comment by him "Trickle charging lead acid all night with lithium seems very inefficient" is 100% true, but in my case I consider this effect a bonus b/c the lithium acts like a capacitor for the solar array (quickly charges, then slowly charges the lead!)
You're right, I think my situation is similar to yours. My solar array is not so big (for now at least) so I have lot of power in the noon but less in other times, so it will be very helpful to have a lithium pack that absorb all that power quickly and then feed it to the lazy lead pack over the next few hours.
I have 1540W and it's enough to cover more than 16hrs of power outages (light fridge, fans etc...), but I'm planning to expand as things are going wild in the near future probably. I'm afraid at the current rate of wars and energy insecurity even some rich countries will face the issues we're facing and we will be even worse!
I used to have an Epever MPPT. Really nice unit. However, as I recall, the manual emphasized that you should only use solar panels for the input. This is because when the battery is full the MPPT will stop charging by shorting the input. This is fine when the input is solar. But if you are doing LiFePO4 -> MPPT -> lead, it's going to short out your LiFePO4 battery when the lead battery is full, which would be very very bad.
Woah, you can get a 10kWH LiFePO4 Powerwall for $2600. I didn't realize heavy battery tech is that far ahead. Seems rather compact too. That just seems entirely reasonable to install in your garage.
This is why I'm always mystified by the hoards of people that say that batteries will never be a significant grid resource. They are getting incredibly cheap already, even as our demand is exceeding supply.
There's some great modeling by Christopher Clack about how deploying tons of small storage and solar on the grid edge (at homes and businesses, next to the meter), and doing it right now, will enable far far more penetration of utility scale solar later.
Because, contra utility talking points, distributed solar and storage is actually a massive grid asset that lessens the transmission requirements and greatly lowers the overall cost of our electricity system.
We have the technology to get to 80%-90% renewable energy today, and at today's prices it will be cheaper than our current system. And by the time we get to 80-90% renewable power, other tech will have advanced far enough to go the rest of the way.
We just need to reshape regulations and markets so that the cheapest grid can be built, and that grid will be carbon free, and cause massive amounts of wealth generation. The only losers in this transition will be the corporations that fail to make the right bets on the future.
I'm still thinking about this. What is the benefit of adding lead if you don't fully discharge the lead? Or do you?
If you are only using the lead until the LiFePO4 are dead then what is the benefit? Or do you have something to disconnect the batteries with they are at 50% (or what 55% to be safe) charge?
So you can increase the battery capacity by 50% of the lead you buy instead of 100% LiFePO4. Which means the lead needs to be half the price or less (excluding the cost of the DC-DC charger) for it to make sense.
In a setup where you only move between 80-100% charge for most of the time, dip to 50% maybe once a month, and to 10% once a year.
It's kind of like tiered storage on a file server: most capacity is rarely accessed but still valuable to have, so instead of using a lot of mediocre storage devices you use a few really good ones and a lot of really cheap ones. The good ones will stem most of the read load, and buffer writes to the slower storage if necessary.
> What is the benefit of adding lead if you don't fully discharge the lead? Or do you?
You do - but not always. If you only discharge the lead 1/10th of the time, your lead batteries will last incredibly long (if otherwise properly maintained).
Additionally, lead doesn't take up charge quickly. Putting in Lithium allows you to take full advantage of your solar. This can be mitigated in other ways, but this makes it "easy" and a not complex system with many charge controllers, many batteries, etc...
Additionally, it allows your input voltage to be much higher (from the solar) meaning you can have smaller wires (but amps are amps!).
> If you are only using the lead until the LiFePO4 are dead then what is the benefit? Or do you have something to disconnect the batteries with they are at 50% (or what 55% to be safe) charge?
I'm not sure what the question is, sorry. Yes you have equipment to make sure you are safely drawing from the lithium and safely charging the lead.
> So you can increase the battery capacity by 50% of the lead you buy instead of 100% LiFePO4. Which means the lead needs to be half the price or less (excluding the cost of the DC-DC charger) for it to make sense.
Well, if cost is not a problem, it would be better and a more simple system if you bought 100% LiFePO4. But that is really expensive.
You want your LiFePO4 to absorb the day to day brownouts/outages as well as sunlight variation and charge/discharge, and you want your lead acid there for when you get taken off the grid for 3 days and maybe have your solar ripped off your roof or partially degraded, once every ten years.
You also can afford to capture more energy faster and charge your lead acid slower - vs just dissipating the extra the lead acid can't use as heat.
>get taken off the grid for 3 days and maybe have your solar ripped off your roof or partially degraded, once every ten years.
Depending on location, the "taken off grid for 3 days and having your solar ripped off" could be from the same storm situation (hurricanes, tornados, etc)
If you are draining the LiFePO4 batteries faster than you can charge them and the lead batteries are charging the LiFePO4 batteries than wouldn't you have the same problem that will reduce the lifespan of the lead batteries?
You would probably need switch (battery isolator, Dc-DC charger, etc ) of some sort to isolate the two systems to fully eliminate this, but part of the answer is the Lifepo4 keeps its voltage higher through most of it's capacity than lead does. Thus the voltage of a Lifepo4 at ~20% is the same as a lead acid at ~100%.
This is true, but in my case I use a DC-DC charger that does not allow the lead to charge the lithium (I don't want this or want to think about it, even if it was beneficial, in my case the complexity is not worth it) - the only way the voltage can travel is from the lithium to the lead.
Solar -> Charge Controller -> Lithium -> DC-DC Charger -> Lead Acid -> Load
The load is always pulled from the lead acid, but in reality if the load increases your DC-DC charger will just put out more juice (until it hits its limits) and not really drawn down the lead. If you max out the DC-DC charger yeah you'll start to draw from the lead but that is ok - that is what it is there for.
For a really large bank that you need to draw down lots of amps you may need to rework things, but likely lead acid doesn't work for you in those cases anyway. This works for banks where your load is like 50 amps or less. For my case, I have 1kAH including the lithium and I do not ever draw more than 20 amps. Works great.
Sorry if I was unclear - it is the other way around. The LiFePO4 is before the Lead. So it is:
Solar -> Charge Controllers -> LiFePO4 -> DC-DC Charger -> Lead -> Load
In this configuration, yes, the lithium is always charging the Lead, and the DC-DC charger is creating heat. But the DC-DC charger is not two ways. So the lithium does not get charged.
But the benefits are above, and also you can make the lithium bank a higher voltage bank (so 24v, or 48v, or whatever) which has benefits for your solar: you can use smaller wire.
Not sure - but very easy to make with off the shelf Victron products. I use their DC-DC charger and their charge controllers and have had great success so far.
With RV Lead Acid Batteries, you typically can only discharge half of the battery safely. So a 100Ah battery really gets you 50Ah. With the LifePo4 batteries (also much less fire hazard than regular li-ion), you can regularly discharge >90% of the capacity.
>(One) trouble with lead acid is that deep discharges are really bad for the longevity of the battery.
Let me introduce you to the Optima Blue Top[0] marine battery which is designed specifically for draining to 0 and recovering to full charge. Doing this to a typical SLA battery found in cars is definitely not recommended. These are commonly used in fishing boats to run trolling motors and pumps in the boat's live wells. Being the hacker nerd type, I built a DIT cart around these with an inverter to power my gear in remote locations without needing puttputts.
Are the Blues much different from the Yellow Tops?
I've been running Yellows in my Jeep due to the heavy electrical load from the winch--I've nearly drained the battery a few times having to winch myself out with the motor off--without issue.
From a quick glance, they seem to be the same construction?
It's been a long while since I looked at the differences. I know the red top are typical car use for starting with high surge loads. these are not recommended for deep drain usage.
There are 2 blue tops, and just realized the one I linked previosly is not the same version (dark gray) as the one I have being the light gray.
Essentially, the differences are in use cases. Lots of short but heavy loads vs long sustained loads. Looks like the blue tops are still Optima's best "drain to 0 frequently" type of battery where the yellows look like an occassional drain to 0 is survivable but not the recommended use case. I had forgotten the differences after making the decision years ago. Just looked them up again for a quick refresher
> The batteries themselves typically last >5years in a car
In a home you will be using up a good chunk of the capacity every night. Lead acid batteries don't last many cycles[1], and I suspect you would be replacing them every 18 months if you powered your house off them.
Boats often have a solar+lead acid setup, and the owners of such systems typically have to make lifestyle changes to adapt around the limitations of the power system. Things like running only one appliance at a time, only starting the washing machine if the batteries are over 50%, never use any electric heaters, etc.
Not really - lead acid batteries are limited to only using about 50% of their capacity, go any deeper more than a handful of times and you'll pretty much destroy it.
No, they're not. It depends on what battery you pick, and if you go with a deep cycle battery designed for that sort of storage use, you typically get charts of cycle life down to 80% DoD or so, and still have "hundreds of cycles" there on anything competent. With thousands of cycles for shallower cycling that you'd see on a daily basis.
Please go find a good, modern lead acid datasheet and familiarize yourself with it, because I'm tired of people who've clearly not been around anything from the last decade or two parroting this line endlessly when it comes to lithium and lead.
The apples to apples comparison of capacity kWh is misleading. The cheaper lead acid should not be discharged below 50% regularly, cutting the useful kWh in half for regular use.
When I did the math for my RV on Lifepo4 vs lead acid, the cost per usable kWh was higher unless you looked at the expected lifetime replacement costs, then it was even. I haven't followed battery prices too closely but my impression is that Lifepo4 has dropped in price ~30-50% since then so is probably now cheaper for usable kWh×cycle than lead acid but still might have a higher upfront cost.
The supported tempurature ranges, space contraints (venting, size, weight) and other factors all seem to favor Lifepo4.
That said, if your house battery is a backup for power outages and not intended to power your house every night, then lead acid may still be the way to go because you don't care about kWh not kWh×cycle.
Is there any data about battery safety, like NiMH vs LiFePO4 vs lead acid [add your favorite chemistry here]?
I understand LiFePO4 batteries to be exceedingly safe. They don't overheat or catch fire even if punctured.
Lead acid batteries, well, contain lead, which, as a father, is not something I want in our house. It can also produce hydrogen and oxygen, potentially causing an explosion.
That is basically what a forklift battery is. You can pick those up for the scrap cost of the lead as many places either recycle them on a timeline and not when the battery is dead, or recycle them when a cell or two needs replacing. I've seen forklifts with 20-year-old batteries - being in a heated climate, never being deep cycled, and the purity of the lead are all factors in longevity.
Lithium Titanate (LTO) is the only lithium based home battery I would feel comfortable with but same sentiment on safety. The chance of thermal runaway is low but results are catastrophic.
It's basically LiFePO4 but even more so: really high charge (10C! and it doesn't even get warm to the touch) and discharge rates, even harder to damage to the point of failure, and really long lifetime (many, many full charge/discharge cycles). Slightly worse energy density. Main downside is it's pretty expensive and niche still. I wouldn't necessarily consider it optimal for solar power storage, where it really shines is high duty cycle high power operation like electric busses, because you can fast-charge it multiple times a day for years.
Spot on. The cost is definitely the main issue IMO. I think they make for great option for home backup/offgrid use mainly due to their crazy high cycles like you pointed out. An Australian company (Zenaji) sells a solution with a warranty on 22,000 cycles. Again, super expensive (~$3k AUD per 1.95kWh) but IMO a superior tech other than density (not a huge difference but definitely not as good as LiFePO4/NMC), which doesn't matter as much in home/commercial stationary backup scenarios.
Yes I've seen very little about lead acid batteries for solar storage. Considering that home installments are almost never weight constrains and often size is not a big issue either, they seem like a perfect solution. I wonder if there is some important bit of information missing that makes them unsuitable?
The cheap lead-acid batteries you find in your car don't handle deep discharge very well, let it go empty a couple times and you have to replace it (at least they can be recycled easily). There are variants that can handle that better, but they cost easily twice as much. If you charge them too much they start venting hydrogen, which could build up to dangerous levels in buildings. I think that was discussed as a cause in the OVH datacenter fire.
So they do have some problems, but still almost all battery backup is done with lead acid (with lithium-iron catching up as a good replacement). I think most of these li-ion backup batteries are more about using surplus production when you scale your battery production faster than vehicle sales.
There is really nothing "perfect" about lead acid.
They let out fire-hazard gases when they charge.
You need to maintain their internal water levels.
They tend to spew acid on their surfaces.
Their voltage droops as you use them.
They can't tolerate deep discharge at all, and in general wear out quite quickly when heavily used.
Lead acid batteries are commonly used for solar storage.
They require more physical maintenance than lithium ion, and they have more specific charging requirements.
Having 20 lead batteries in your basement also adds a lot of prepper flair and scares away those annoying fire protection guys too. It is just 10kWh regardless of voltage aside from small conversion losses here and there.
Provided you have a computer that uses 500W, a monitor that uses 100W plus your internet router of 20W, you can run it for a bit over 16 hours. Just answering the important questions.
Although these type of battery also wants to be handled correctly. Don't discharge completely and yet also do not charge them fully. You also have to know about the hundreds of other partially true myths about lead batteries. Their most prominent positive property is indeed the price and not too much else.
Where would a city dweller put a huge battery pack anyway? Maybe ask your landlord to put one in the basement for the whole building? Obviously he won't; it doesn't provide any benefit to him.
> Honestly I'd rather a battery that's super reliable and NOT using any lithium ion inside it in my home. As it doesn't need to move, it can sit there in an unused space and be really heavy.
It sounds to me like you're asking for a nickel-iron battery.
You want about 20kWh at a minimum to be self sufficient. We have a 10kWh Tesla battery, and it only lasts until the evening (saving 20%) for grid outage backup.
That's probably at "full load" for your house though, no? If you're looking at an extended outage, you can alter your use patterns.
I have a 5kW gasoline generator that most certainly cannot run the whole house, but in emergency situations, I turn off most things at the breaker box. We can run one AC unit to cool part of the house, then shut down that, and power up the kitchen for dinner, etc, etc.
Because this really depends on climate and the house.
In our case, 100 kWh would be required to cover one day normal power requirements in the worst case. Median would be about 50 kWh.
I could probably stretch 100 kWh for max 3 days (worst case) by adjusting temperature, using water minimally and unplugging everything that's not absolutely required.
There are also households who could stretch 8.7 kWh for several days. And houses that require significantly more power to maintain liveable conditions.
Some places on this planet can get very cold or very hot. If you're running a [ground source] heat pump as your primary heat/cooling source, even with high COP, on extreme days the system can draw massive amounts of power.
You know, those days when losing power could truly hurt. Like destroy water pipes (including underfloor heating pipes) type hurt. Or make the house unlivable hot.
No bragging (I have no idea how someone could read it like that!) or anything. Just facts. There's more variability than you might think.
It's unclear, but if this is Toyota's proven NiMH technology from the Prius, rather than Lithium technology (i.e. in the Tesla Powerwall), I'd personally opt for this.
It will last longer, and is a lot safer. Unlike Lithium, NiMH is not particularly unstable at high temperatures or flammable. And Prius batteries have been proven to last more than 20 years (at reduced capacity) without any safety problems -- we don't ever see Prius' catching fire.
a) it will not necessarily last longer, li-ion in the right conditions (particularly more stable chemistries) have superior cycle life experience in practice
b) yes, newest batteries decay slowly over time and don’t ‘just die’ - but this is the same as li-ion
c) safety is mitigated in the modern setting by utilizing the same charge controllers used to keep EV car batteries safe. Remember most North American homes with a natural gas furnace literally is a controlled blast of explosive gas without a smell that people just have and don’t think about - as the tech goes on the learning curve the management issues (I.e. disconnecting faulty cels individually) seems like a plausible end solution, even if that is necessary.
Lastly, while NiMH does not use soon to be very scare processed lithium, NiMH uses very large amounts of nickel, cobalt and comparatively exotic ‘rare earth metals’ who’s production should be expected to be even more challenging to scale.
All that said - I am all for us scaling up all of these technologies so that each can fit within a particular market niche based on inherent pros and cons.
The headline of the first article is "Toyota is recalling 1 million hybrids at risk of catching fire", did Tesla ever do any similar recall, because of potential fire risks?
You've probably never seen an old Prius. Here in Fiji, our roads are filled with second-hand Priuses (from Japan), and we have a Prius fire every two months at least.
Perhaps look at the BYD batteries, they are LiFePO₄, which is a lot safer than the Tesla Powerwall (I believe that is NMC?). It should also last longer under the same cycle conditions. The only downside is it is more temperature sensitive in terms of capacity and life, but that could be mitigated by for instance installing it indoors.
I was under the impression this chemistry is a lot more unstable but denser and lighter. Isn’t it what is used in drones and you have to charge them inside a firebox because they’re more prone to thermal runaway?
Eh, people have to charge drone batteries carefully not because of chemistry, but because of sketchy industry norms.
Almost every other industry making lithium-battery-powered products insists on 'genuine' batteries and tells people buying third-party replacements is taking your life into your own hands. Drone enthusiasts, on the other hand? Ordering batteries from unknown suppliers on ebay or aliexpress isn't unusual.
And even reputable drone battery brands face the temptation to advertise a spec without any safety margin, to stay competitive. If all your competitors advertise '90C discharge' on the assumption they get the cooling of the drone's fans, you gotta follow suit to stay competitive.
At the same time, can you think of any other application that takes a battery from full to empty in 15 minutes? Or an application that runs its batteries without a BMS, fuse, or battery temperature monitoring?
(Of course, in a sense that's a reasonable state of affairs - shutting down because the battery's overheated isn't exactly a safety feature for a drone, unlike for a battery drill or vacuum cleaner)
LiFePO₄? Drones probably use LiCoO2. It has a much higher energy density and higher C-rate than LiFePO₄. LiFePO₄ has a much higher thermal runaway temperature than NMC (and other chemistries).
I found this article with a short summation:
https://www.newcastlesys.com/blog/lithium-ion-vs-lithium-iro...
The drones you're thinking of here (FPV stunt drones, racing drones) have the most demanding discharge profile of any use for lithium batteries.
The whole drone is built around draining current from the smallest possible battery, as fast as possible, right up to the limit of safety. Charging is also a faster-is-better thing, from a pilot's perspective.
This kind of maximum discharge raises the risk of dendrite shorts considerably, which are what pops a lithium battery usually. So a firebox is a good idea for this case, it's just inherently dangerous to be right at the limit of energy-per-gram and discharge capacity all the time.
The chemistry is also never LiFePo, which is too heavy.
That source mentions BMW and Chrysler hybrids as problematic. (go figure) Toyota's NiMH batteries have a very good record for reliability and safety going back two decades.
Hybrids on average have a greater fire risk because they have more opportunity for mistakes -- they have both the spicy components from an EV and the spicy components from a gas car.
The good thing about grid storage is that you don't need the weight and density of lithium. That's especially good because it looks like we don't have enough lithium for electrification of transportation. Lithium supplies will improve in a few years, but right now I think we should incentivize using lithium in mobile applications. There are plenty of technologies for power storage that don't use lithium.
NiMH is "better" for residential (in my opinion) in the sense that it is more inert than any Li-based battery. If you crush or set fire to LiFePo4, it will burn.
What's interesting is because Toyota has been developing the NiMH for so long, it has achieved densities of approx. 150Wh/kg, which actually makes it about as good as Lithium technology from 5 years ago, but without any of the stability problems.
NiMH were incredibly annoying back when I last messed with RC cars, which was when NiMH was the latest and greatest battery chemistry in use there. They rarely delivered in practice what was in writing quite promising capacities, and they were incredibly delicate when it came to heat.
The wikipedia page for NiMH also mentions things like venting hydrogen gas when overcharged...
Looking through the LiFePo4 pages on wikipedia the safety and durability profile seems superior to NiMH, but maybe the LiFePo4 pages there are just fixated on vs. other Li-Ion chemistries.
My impression ATM is if you've got LiFePo4 available it's preferable to NiMH. And my personal experience with a LiFePo4 portable battery booster for jumping cars and emergency charging stuff has been an incredibly positive one. The thing is like a tiny weightless magic box that tolerates incredible abuse without losing any charge even stored for a year in desert temps, and somehow manages to put out enough current to start large-displacement high-compression V8s.
What's interesting is because Toyota has been developing the NiMH for so long, it has achieved densities of approx. 150Wh/kg
This is an interesting point; why hasn't Toyota made longer-range plugin hybrids with these batteries, which would seem to be sensical? Looks like the largest battery in a plug-in Prius so far is just 8.8 kWh, according to Wikipedia.
I would guess that there is not much room for them to develop the battery technology further, as it seems they are close to the absolute limit of the materials' performance.
So to start a plug-in hybrid program using that battery technology, could be very bad (outpriced, outperformed) if there was suddenly a huge leap forward in Li density and safety.
NiMH's faults can be compensated for by managing recharge and discharge cycles - toyota has specialized in this for a long time, it's a few steps above your average AA battery
They just only use 40-80% SoC; it's nothing special to carry 2x+ the battery to try and make up for an inferior chemistry.
That also doesn't compensate for the high self-discharge rate.
I'm just happy to see more competition in this space. More competition will drive down costs and increase innovation. Give me 20 companies all trying to sell me the perfect solution for my home, please!
When we reach a day that most homes have a basic battery like this in them to balance their power draw, power sources like wind and solar- which have variable output- become increasingly more economically viable. Oh, you can only produce when it's sunny/windy? That's fine, half the homes in the country are willing to pay you for energy right now and then use it later when it's not.
What I'd love to see next: larger units for condo/apartment buildings. Put a massive battery pack on the roof, or next to the parking garage. Because of the shared draw, there would be a very consistent daily pattern of use, and you could right-size the battery to ensure maximum utility of it.
F150 is 98 kWh standard range, 131 extended. But the important point is this sentence:
Toyota explained that the system supports supplying power from hybrid electric vehicles
Presumably, this means you have a short, medium, and long option for emergency power:
- short: the battery
- medium: the battery + your car's battery
- long: use your ($25K) Prius as a gas generator to power your home for as long as necessary.
This seems like a more versatile setup than the e F150 at least for my use cases (rural WV -- power might be out for long periods but I can always get gas). It'll be interesting to see the price range of course, but this could be a good "mostly battery + gas if needed" backup option to compete with the diesel generator situation now. And of course the eF150 isn't really a good backup power (or transportation!) option in my case.
The eF150 generator use case always seemed like suburban prepper fantasy bullshit. The actual use case is for running power tools on site.
> The eF150 generator use case always seemed like suburban prepper fantasy bullshit.
Perhaps you didn't hear about the millions of people who were miserable (and several who died) because their power grid is run by morons[1].
Losing power for three days may have been unusual for a long time, but with the combination of radical/unaccountable government, climate change, and aging energy infrastructure, it's easy to imagine that a lot of the warmer parts of the US are at some risk.
I live about an hour from San Francisco and my power goes out about once a quarter for several hours. It's not the end of the world, but twice in the last year it happened while I was making dinner. A weird feeling to realize I can't even make food without the governments help.
I’m planning for solar cells and looked into the possibility of running my house as a micro grid (ie disconnect it from the main grid) in case of a prolonged power outage. Turns out that unless you redneck engineer it, running your house without a main grid to synchronize to is very costly - among other things you need to supply your own grid grounding and that could easily run into the high €x000.
In Europe (EU) every house needs own grounding. You are not allowed to ground on main grid's ground. We have three cables: 1) power 2) zero (=main grid's grounding) 3) own grounding. Only old installations are allowed to connect grounding to zero which is called something like "zeroing".
In the UK, which was until very recently in the EU, most modern (last 20-30 years) houses have what’s called Protective Multiple Earthing where the house earth is just connected to the incoming neutral and there’s no earth spike at the house. Then the power company earth-bonds at the substation and several points between the substation and houses.
I believe metal pipe bonding is a building control requirement however many new builds use predominantly plastic pipe work. The requirement is to protect the occupant against touching live metal pipe work, not to earth the house.
Here in the US, I have three wires from the utility: phase 1, phase 2, and neutral. I also have two copper ground rods that are 3-4 meters in length, which are connected to the utility neutral.
At the first electrical panel in many cases the grid's neutral is connected to the house grounding, this is done in new houses in my country as standard.
Stake in the ground, as the sister post said, non-corroding, in the simplest case.
But there is more to it: The stake has to have permanent contact to some electrically conductive layer in the ground, so you need to take geology and local climate into account. In central europe, with generally wet climate, you just need to reach the year-long stable, frost-free, local water table at a depth of (usually) between 1m and 10m. If you cannot reach sufficient depth, don't know the required depth, a simple stake isn't going to cut it. Because in case of an electrical fault, the grounding has to withstand and dissipate in the order of a few hundred Ampere. To achieve that you then shallowly bury lines of non-corroding material in a grid, or bury a grounding net something like 1 to 2m deep over an area of 100m^2 to 10000m^2.
If you are on sandy or rocky ground, permafrost, arid climate and no handy body of water is nearby for grounding, you need to have a far larger grounding net or use conductivity-enhancing methods like permanent watering, adding salts or carbon to the soil or replacing it outright with something more conductive. In all, very expensive.
And as for large installations, you just measure the soil conductivity, calculate the necessary grounding current and scale up the aforementioned methods.
This must be a European design. In the USA, governed by NFPA 70 - The National Electric Code, the ground rod's purpose is to establish the ground voltage reference to reference the electrical systems of a building to it and to dissipate any charge buildup on the circuits.
The ground rod is not there to carry current to interrupt a fault to "protective earth" - the green or green/yellow. The circuit breaker interrupts a short as you bring the protective earth wire back to the main disconnect of a building where it bonds to the neutral wire.
If a fault occurs, an unregulated amount of current flows on the protective earth wire to the breaker panel and a circuit breaker interrupts the circuit.
I'm no expert, but here in Norway we predominantly have IT systems[1], though new installations are mainly TN.
In the IT systems, the protective earth is not bonded to the neutral. Thus in case of a fault, the protective earth should be low impedance to ground so that the circuit breakers trip. At least that's my understanding.
Technical nitpick, if it detects earth leakage and trips based on that, it's an RCD, not just a circuit breaker. Otherwise yeah, there's different approaches to earthing - in Australia for domestic stuff we have mandatory RCDs which work as you describe above, but then also in industrial/mining settings we have the big green/yellow cables which will directly sink current (potentially hundreds of amps) to ground, hopefully stopping you from getting bitten.
A thermal breaker won't trip on leakage current or arc faults either. I was trying to describe the classic "dead short" that will trip a thermal circuit breaker or fuse without the circuitry for arc or leakage detection.
Ground water isn't really receding, it's just pumped to a low level to benefit agriculture at early spring, which then fucks everyone up if the spring and/or summer is dry.
Usually you can just tie it to an outside copper plumbing pipe, it's metal and makes good contact with your local ground.
Disclaimer: Not intended in any way as professional electrical advice yada yada. Just what I've read.
(Also all sorts of weirdness can take place around grid earth vs. local earth, eg. during thunderstorms. Earthing is its own entire engineering discipline. :S )
You need to put as much as needed to achieve 4 Ohm to ground or less. This can be up to ~ 10 stakes at a couple of meter interval, it depends a lot on the soil type.
You also need a transfer switch to make sure you're disconnected from the grid otherwise you're going to be feeding power back into lines that are supposed to be dead.
I already have a 2000W inverter wired to my Prius' 12v battery. Pop the car in ready mode and I can run things off it for ages, and then unplug them and go refuel the car if needed.
Having the extra storage battery mounted at my house would be cool and all I guess, but you don't need this to back up your house's power supply with a Prius.
(I live in a small, simple house and only run the blower fan for my propane heating system, my refrigerator, my freezer, and a lamp off the inverter. I suppose if you had much more complex power needs, the battery would be a larger advantage, but for emergency power outages, it keeps me from freezing or losing all my food.)
Honestly I kinda already did. Connect 2000W pure sine inverter to terminals on 12v battery in trunk. Plug in extension cord.
It's not terribly sophisticated, but it keeps my pipes from freezing.
Refueling a car is as easy as it gets, though. To refuel anything else, you'd have to put it in a car and take it to the fueling station anyway. This way you just refuel the car the normal way. You can also store whatever gasoline you'd have used in a generator at home too, but the Prius' 10.9 gallon tank holds a lot more than your average portable generator and runs a good, long while.
Running your home off your car's combustion engine sounds like exactly the wrong way around. I want a battery that allows me to save days worth of power from solar panels to use during cloudy days.
Well, I suppose if you have enough panels to generate power even on short, cloudy winter days, then that doesn't matter anymore; then you just need enough storage for the night. But then what are you going to do with all the surplus power on sunny summer days?
Some sort of cheap long term storage would really help a lot.
At least for our install, we spent about half the money on batteries and half on solar. It fairly reliably gets through the night unless we run the AC (but those are sunny days) or charge the car (car batteries are about the same size as the house batteries).
On a cloudy day, the panels provide 90% of our normal power usage. Anyway, to scale it up, we'd want to increase panels and also batteries. Increasing only one would leave us with no power at dawn or with a large battery that would never reach 100% in winter. One night of batteries with panels that reliably provide enough electricity to get the batteries to 100% is a good tradeoff for sunny climates. As it gets cloudier, batteries might have more incremental benefit, but multi-day storage probably doesn't make sense.
Also, you can tie a gas/propane generator to the battery to handle the "a few times a year" cases. That's probably less carbon intensive than 5x-ing the system for 1% of the days.
(Since the 1% days for us are in winter, we have a wood stove.)
> But then what are you going to do with all the surplus power on sunny summer days?
You don't have to do anything with it. Panels are dirt cheap these days, and if you want reliable off grid storage then you have to size them to keep up with baseload power under your target range of conditions anyway. Figure out how many days a year you're happy to run a generator or turn your fridge off, find stats on your local daily kWh/m^2 solar energy, size panels to cover baseload with that incoming energy.
I have 2kW of second hand panels hooked up to a 200AH 24V battery pack (again second-hand) to power a server rack, it uses about 4.5kWh of solar power per day without running the batteries down too far. The panels can generate 8kWh/day in summer, the rest is headroom for cloudy winter days. The last time the server saw mains power was... December, I think?
> Some sort of cheap long term storage would really help a lot.
Generating some sort of fuel is probably the best idea indeed. Hydrogen is often suggested because it's easiest to create out of water, but it's also hard to store. Ethanol is definitely easier to store, but requiring a lot of biomass is definitely a bit of an obstacle.
Genuine question - how many engines can run on straight ethanol? Are there any negative consequences for running straight ethanol in an engine expecting gasoline?
Yes, I get it, it's indeed a lot of surplus in the summer.
Long term storage would be the better solution, but batteries don't seems to be able to store a large amount of energy anyway. So in my opinion, it's really a tradeoff.
I looked into this. Even assuming PG&E's buy back rate is 50% of current numbers, the ASICs have an expected profitability horizon of over one year of uptime. I'm not convinced they'll be profitable much longer after that, since hash/kWh keeps improving.
Also, I bought the panels to reduce carbon emissions, and would rather sell the power back.
> The eF150 generator use case always seemed like suburban prepper fantasy bullshit. The actual use case is for running power tools on site.
I think the Hybrid F150 / generator case is pretty decent; not so sure about the EV only generator one, but running tools could be useful. Rolling a truck over to my well when the power goes out will be a lot nicer than rolling out a portable generator by hand. Could be maybe useful for cell towers that rely on generators driven to the site during outages as well; although that depends on if they usually drop off a generator on a trailer and let it sit without local supervision or if they stay with the generator. My well servicing company has a box truck with a generator in the back, that they use to confirm that the problem isn't related to utility electric service; not sure if a built up f-150 would be sufficient for their storage/transport needs though.
Let me introduce you to the Eastern Seaboard and Gulf Coast of the United States of America, where people often run generators intermittently for weeks after a hurricane in order to keep their refrigerators and freezers cold until power can be fully restored.
In that case, the prius prime battery alone is probably sufficient for several days. And it's 30K less than the eF150. And you can actually buy one off the lot today. :)
I don't heat my home with electricity, and I am not home at the moment. Without lighting and cooking it does 4kwh/d.
When I am home and cook, wash and have the lights on I do about 7.
Factoring in the heating (Swedish "fjärrvärme", remote heating. Hot water from a central plant) I do A LOT more. Something like an extra 30kwh/d in the winter months for a 120 m2 home with half-decent insulation by Swedish standards.
I measured a groundsource heatpump to consume about 30-50 kWh per day in -20c for hot water and heating a 100m2 house. About 22c indoors in a 70s somewhat poorly insulated 1-story brick/stone house. A good 1/3 of that energy goes to hot water.
In houses where hot water is heated with electricity the ratio might be even worse.
Another data point: 180m2 house renovated in 2009, very well insulated, brand new 5.1 COP GSHP equipment we averaged 36 kWh per day for heat in January. We generate some hot water from that but our primary hot water is resistive electric.
Another data point: Our fairly old house, heated with an air heat exchanger, use about 60 kWh per day during the winter months. The power draw for heating is reduced to almost nothing during the coldest period when the outside air is too cold and we use firewood.
Apart from heating the house, we also use some power for hot water and pumping water from the well into the house.
When my apartment was empty for a few days last month, it used 2.2kWh/day.
I used 1700kWh of electricity last year, presumably mostly on cooking and the fridge-freezer. I don't have the district heating (fjernvarme) bill to hand, but that wouldn't be comparable to a house anyway.
Full size fridge and freezer from 2015, forced ventilation fan (which is probably around 35-60w), one server (a repurposed office computer) and 2 WiFI hotspots, one of those Google speakers, a router (USG) and a PoE switch. Those are the big ones.
We didn't build the house, so there are all kinds of standby stuff (including needing smart lights for most lights, stove, towel heaters).
I didn't turn these things off because my mother in law is using the apartment a little while we are gone.
4kWh is 166W average, which is a refrigerator and a couple WiFi access points, a camera, a home assistant device, and some other random plugged in devices (i.e. cordless phone).
Indeed. I just looked up the heat loss for my house: 213W/ deg K. So, to maintain 20 deg C inside with -20 deg C outside requires about 8.5kW of heat energy (200m2 single-family house built around 2008), or approx 200kWh/day.
Generally by using the dimensions and heat conduction properties of the exterior surfaces of the house (area of foundations, walls, windows, roof), taking into account the heat gain due to sun, with some local fudge factors applied (loss due to wind, natural ventilation, outside temperature).
Then, after the building is actually built and inhabitated, the calculations are adjusted by the actual energy consumption over year).
As pointed out, competent HVAC companies should have people on staff comfortable with such calculations. However, my experience shows that it is not universally true, and many are just guided by intuition/experience with other projects (i.e. the roof insulation thickness on the previous project was X, so that's good enough for you, or "well, on average we recommend 50W/m2 of heating power when selecting a heat source"). Which probably works fine for many cases (e.g. renovating an older building, where even if the material properties when they were new are known, you can only guess the values after 20 years of service).
Even a very well insulated home can use quite a bit of electricity.
The most rigorous standard for home efficiency, the Passive House standard, stipulates that no more that 15kWh/m^2/yr is used for space heating. For a 200m^2 house, that's 3000kWh/yr.
Given a 120 day (4 month) heating season, that's 25kWh/day average just for space heating. Obviously it varies quite a bit, with some days much higher and others much lower. Add in other electricity uses, like refrigeration, laundry, and you're easily at 40+ kWh/day even in an efficient Passive House.
That is obscenely high. Where I live, it would cost over ~~150k~~ 7k USD to use that much power every day for a whole year. How is it even possible to use this much energy??
This means that you pay ~4 USD per kWH. That's almost 12 times more expensive than in Germany where electricity is supposedly expensive. Where do you live?
Wow, how is 100 kWh/day even possible? We consume about 3 kWh/day (excl. heating) in our standard-sized 2-person Dutch household, living pretty normal life.
Its going to be 39C at about 60% humidity today here with a bright sun beating down. My home has some decent insulation, double paned low-E windows without metal framing, thick attic blown insulation, etc. AC is set for about 26C. I'll probably still use about 70kWh of power today with the majority of that being the AC. A pool pump uses a good bit of power too though, pumping about 60,000 gallons of water through the filters uses a good bit of power.
You can do 3kWh maybe if you are not cooking using electricity or running a cleaning machine for dishes or clothes.
I've installed an electricity meter 2 weeks ago, and the lowest it got was 4,8 kWh/day in a 2-person Croatian household, although I do have a small Synology NAS running 24/7 and we have a TV on for a couple of hours.
2 Adults, 2 kids, also close to 10 kWh per day (cooking on electricity (induction) but showering on natural gas, 0.6-0.8 m3/day). When we are not home, it's about 4 kWh per day (2 freezers, 1 fridge, home server, router etc). Big sources are Laundry, dishwasher, hot water in the kitchen (5L boiler).
But we heat the house on gas, and last december we burned about 180 m3 of it. Now, during summer, (in the Netherlands) we don't need heating or air-conditioning.
2 adults, 1 kid, belgium. One adult is always WFH (we alternate). Average of 13KWh per day. There is a server rack running in the basement though 24/7 but its optimized (nucs and rpis and no costly energy burning servers) and this rack alone accounts for 3-4 KWh per day (out of the 13)
We heat and cook using natural gas.
The biggest consumer are the same here. Dishwasher and laundry.
Not sure how you are managing this, are you sure your numbers are correct? When I turn my kettle on it consumes more then 2kW, yes it is running for a few minutes at a time but it all adds up, not to mention the electric oven.
With all major appliances off (except the fridge/freezer) I consume ~0,13 kW/h, that adds up to 3,36 kWh in 24 hours.
24kWh a day here. Fairly large house near Cape Town, South Africa. This is excluding heating in winter, for which we mainly use a slow combustion fireplace and also natural gas. Stove is also natural gas. Rarely use AC for cooling.
Easy, live in a house 4x the size of a 2-person Dutch household and in a climate that averages 10 degrees C warmer, like would be common in the southeast US.
I ran your figures through a local price comparison engine. [0] Cheapest rate for you here would be ~12800€, or ~$13400/year. For reference, that's slightly less than half the median net income here. [1]
I also made a quick price comparison between the US and here:
My conclusion is the US provide a reference framework of cheap abundant energy. The environmentally conscious have to deal with a framework that stimulates unbridled energy consumption, with hardly any real incentives for conserving energy.
Update. Local price comparison site was just updated this morning. Price here would be between 14569€ (.40€/kWh) and 17308€ (.47€/kWh) depending on the supplier chose. This includes all taxes and surcharges.
Something is off here, even if both your cars use about 40kWh per day, every day (which is humongous) that would still leave an absolutely staggering 60kWh/day. That would be the same as heating with electric alone a house in the Nordic Lapland during winter.
Given a COP of 5 for a ground source heat pump you can calculate 60/24 is 2,5kW power draw around the clock. Multiply by 5 give 12,5kW heat non stop. That is a lot of heat.
2000 sqft is 185m2 which is a mansion by my standards though :)
Average sq ft for house in US is around 2500sq ft so 2000 sq ft is below median. Ok starter house but not more than that. I understand that houses in Europe are much smaller though due to low incomes and higher utility costs.
I have 2800 sq ft house and use around 30-35 kWh/day in summer. 60kWh/day is high but not outrageously high.
I just ran my last year's electricity. I'm around 26 kWh/d in the DC area in an old inefficient house around 1500 ft^2. While it had a gas stove, gas water heating, and gas house heating, it did have electric window AC units. I'd be really interested in how the previous author had 6-8 kWh/d.
I used about 8 KWh/day when I lived alone in a 1550 sqft townhouse with gas heat and cooking. That ran my IT equipment, refrigerator, and blower fans for heating and exhaust. No AC usage.
Now I'm in single family home and my energy use is bonkers, but most of that is heating while I'm missing part of my roof and an entire exterior wall. It should be criminal for a town to take two years to approve permits.
My last bill I ran 95kWh/day. Smaller house but have several adults and even more kids who all shower and do laundry as well as other things. I wish I could get it down half as much I don't see how I could at this point.
A air-water heatpump for heating that shower water would pay itself back in a few months. Solar panels would get the rest. Water is probably your biggest energy sink.
I use around 70kWh/day (but nearly zero in summer and probably 4x that on colder days).
Heating is a heat pump with probably 300% efficiency (i.e. 3kW heat for 1kW electricity). Walls are 300mm insulated wood frame. Triple glass windows. -20C for at least one week every winter. Could probably lower the consumption by recycling more heat (none of the wastewater heat from hot water running down sinks is recycled for example).
Thats incredible. We use up to 30kWh/day (heating a poorly insulated house), which is almost double the national average household daily usage here in Australia. I guess you really do use alot more power living in a freezing climate.
In a climate I live in (Latvia , -20 degC for a few weeks in winter), reasonable energy consumption for heating of single-family house is around 100kWh/m2/year.
My 200m2 house is slightly worse at ~120kWh/m2/year, or around 24MWh of energy per year (that also includes domestic hot water though).
With a ground/water heat pump it should translate to ~5MWh of electricity per year, or about the same as my current yearly electricity consumption.
I was fairly resistant to Ugg boots and the like, but I realised why they are so popular this year. You really can get by quite comfortably in a Sydney winter without heating. And my home gets cold.
Just to add a point as everybody is going on about how much they use per day or what: You are expected to generate power, too.
With a battery around 9 kWh, you'll probably install a solar system around 3 times as big or sth. like that.
So those capacity has to buffer for the night time when you're sleeping, heating probably goes somewhat down, nobody is cooking on 4 induction plates etc. pp.
I'm in a relatively small UK house. Selling power back to the grid doesn't get you lots of money these days, so the emphasis is on using batteries for night time use. Running off-grid isn't really something that is done, in urnban areas anyway.
Heating is gas, the hob is gas
I have 3kW panels and a 5KWh battery. During the summer hot water is heated through an immersion heater from solar - my electricity bill is roughly zero and I get to sell a bit back. During the winter - forget about it.
That's exactly how you should do it, I think. Generate as much power as you can use for yourself, fill a battery for the night, repeat that cycle.
My landlord installed a 30 kW peak solar system (two households, six childs/people), installed a heat pump and insulated some walls that were not insulated before. Surely a hefty invest, but external power usage has dropped pretty much to zero from February to October. Even after that it's minimal.
There is no reason for such comparison: the point of a small battery is ensure 24h full autonomy for critical loads (fridge, freezer, VMC if it's a new home, lights, computers etc. Batteries are NOT cheap so choosing to limit what's backed up is reasonable.
After, for far bigger backups, a vehicle might be a gamechanger: it need anyway a far bigger battery for it's own performance, so battery costs does not matter much for the use-case and using it once you own the battery...
-20 C to 45 C might not cover every place on earth, but they cover a significant portion. If you had to design a first version of a product, in order to gauge interest of the market, wouldn't you have enough data point with these ? If the number one complaint is "operating temperatures are too narrow, I can't use it", I am pretty sure V2 will cover you.
On top of that, it's pretty safe to say that the true operating marking of the product are wider than that, but that significant safety margins are taken just to be sure a unit does not explode.
> 45 C is not _that_ hot for a black box in the [insert warm place] heat during summer
I've been in a major city that would benefit from power backups like this. The hottest day the all-time heatwave was 45.2 C. So yes it's provably a reachable temperature, one where you _really_ want the aircon to work, and not lose the power.
Toyota's vehicles there have a reputation for being affordable, rugged and long-lived. And mass-produced. So the Tesla Powerwall may be a nice Proof of Concept - if you can afford it, if you can get one, but if Toyota is also in that market, well that's a different ballgame. Far more people will pay attention. All the same, I would wait a couple of years, see if the V2 is much of an upgrade.
“To measure outdoor air temperature on land, the setup is simple. A thermometer is placed inside an enclosure […]. Regardless of the shape, the enclosure is white in color to reflect solar radiation, which heats the thermometer and keeps it from getting an accurate air temperature reading. The enclosure also typically has slatted sides to allow air flow, and a double roof (a roof and a raised roof over that) to protect the thermometer from rain and further resist the influence of the Sun.”
So, they measure temperature in the shade, away from the ground, under a roof that’s painted white.
In the sun things can get hotter. 45 C water for a few seconds isn’t painful, but touching the hood of a black car or the asphalt on a road surface on a 40 C day immediately is.
If it's indoors or in the shade, I don't think there are many places regularly hitting >45C temperatures. Obviously placing it in the sun wouldn't be wise.
The -20C limit could hit more areas, but if placed indoors I guess most should also be fine with that.
And -20 C isn't that cold for outside and close to the floor either. There are places that occasionally reach both. But none of them would be anywhere close to a sea, so perhaps they simply didn't mind extending the temperature range because they start with their domestic market? And then there's the question of what happens beyond that range: will it shut down? Will it go up in flames? Or will or perhaps just age a little faster than rated? If it's the latter, a few dozen hours a year certainly wouldn't matter a lot.
I definitely reach -20 every single year and 45C on a hot day in an enclosed space with sunshine on it isn't unheard of either.
But it's not too much to ask to just create a space for it that's slightly insulated. Making a small space in the garage be within say -10..45 even though outside temps vary -30..30 like they do where I live, is cheap and easy.
I suppose if you don't want it to for whatever reason it'll shut off if it gets too hot (perhaps short of where it would otherwise start cooling) instead?
Upper Midwest here. Our power doesn't go out often, but of the times that it has, I think only twice was above -30 degrees.
It really varies a lot by your utility company though; our coop is quite good for the most part. On the other side of the same state, my brother is in an area more prone to bad storms and tornados, so he's had to deal with several multi-day blackouts. It gets hot here, but not above 40c in the shade, so he'd probably be fine if it can handle direct sunlight. If not, a gasoline / nat gas / propane generator would be far more reliable.
This is great but I also wish that Toyota would start shipping a lot more EVs. They have been far behind the trend and made some poor bets on the future of technology. I fear that the poor renewable resources available to Japan, compared to most nations, has colored their judgement when it comes to the global market.
I would love an EV Sienna, for example. Really hate that moment of filling up with gas with my kids in the car, the cognitive dissonance of fucking over their future in such direct sight is painful.
They and the other Japanese manufacturers have been actually actively fighting this trend. Outside of California where they were required to do stuff by law that is. They're heavily invested in ICE and have been pushing FUD on this topic and marketing dead-end stuff like hydrogen fuel cells as alternative but primarily just to avoid doing anything. They're starting to pivot now, but's pretty late. Toyota/Subaru have brought out some meh EVs now that will only sell because of brand loyalty.
It's a shame because they had a head-start with the hybrid drivetrain concept, but seemed to just want to stop there. And honestly GM's "Voltec" drivetrain was better than anything that came out of Toyota or Honda (too bad it's dead).
I drove around Vermont in my friend's PHEV Rav4 this past winter... and it's... ok. But my Volt is the better machine.
I think non-tesla vehicles are going to struggle in selling in the US in the kind of volume that makes sense for Toyota until they have a decent charging infrastructure.
I think they will struggle but not for the reasons you give. Manufacturers will continue to sell 100% of their inventory. Demand is not the problem. There are no major EV lines for which there is adequate inventory, from any manufacturer.
The problem is supply, and supply-chain. Specifically batteries. And in this case the supply curve is relatively inelastic because getting battery manufacturing online at the required rates just isn't going to happen in time.
Only Tesla has really properly invested in this.
Governments wasted their time giving consumer EV subsidies when what they should have been doing is providing battery manufacturing subsidies.
Yeah, post 2020, that's another problem. If it's hard to get batteries, I'm sure Toyota would rather build 4 PHEVs than one EV.
But, rewind to 2019 when supply chain was not an issue and non-Tesla EV sales were still really bad. The Model 3 was selling an order of magnitude better than the top non-Tesla EV, the Bolt.
Except the Bolt still all sold all of its inventory. They just didn't make many of them.
FWIW I was shopping for one back there in Ontario (when we still had EV subsidies). I ended up getting a Volt because the Bolt was unobtainium even at the EV-friendly dealer I was shopping at. 8 month wait at least.
The prius prime and Rav4 prime are excellent, affordable vehicles. I only burn gasoline when driving across the country (and I can do my usual 12 hour drive with one 10 gallon refill)
They are an old, lethargic company. They won't do anything truly innovative until they cut the fat and get agile. I interviewed with Woven Planet, their automated driving division and it was a complete joke. They focused more on creating motivational videos and designing fancy offices than on solving problems.
They don't even need to innovate, just copy the path laid out to them. They can already make the batteries, apparently, let's just put them in cars and let me stop putting a pound of CO2 into the atmosphere for every mile I drive.
Even better would be able to live in a place that let me have a family without a car, because there was adequate transit. And though I'm working hard on that locally, it will take time, if it ever succeeds. And most parts of the country will never even attempt that :(
They are by-far the most fuel efficient hybrid on the market in Europe at least. The fuel economy for city usage (40-50km/h) is far below other hybrids (not talking about plug-in hybrid here).
That's true, but the short-term choice is mainly between 70MM ICE cars vs 70MM EVs, because car-dependent urban sprawl has already been built, and people living there are very strongly opposed to even smallest changes in urbanization.
They're not saying what the "vehicle adapter" spec is. I'm very curious.
I know that CHAdeMO is spec'd to allow vehicle-to-house, but good luck finding an inverter device that has a connector for. My 2018 Mitusbishi Outlander PHEV has a CHAdeMO outlet, it would be handy to take backup power from it as a generator. (I use the 12Amp outlet package on it for that, but that's only good for 1 appliance really).
If other people are right about it being NiMH this could actually be a really interesting product.
The CCS connector equivalent is relying on the onboard DC-AC converter for V2L-V2G, hence no inverter needed.
The CCS cable uses a resistor between PE and PP pin to allow the EVSE to determine its current capacity, 1–2.7kΩ for single-phase 13A all the way down to 50–150Ω for three-phase 63A. [1]
What manufacturers have done is tap into that and use some resistance to tell the car to go to V2L mode.
- Hyundai IONIQ5 and Kia EV6 use 50-75Ω for its V2L adapter, offering 3.6kW load
- MG ZS uses 470Ω offering 2.2kW load
- Ford F-150 to offer 9.6kW load, but resistor is unknown
- BYD vehicles to offer 2.2kW load but resistor is unknown
The Ioniq5/EV6 adapter only plugs into the J1772 port. This is not how the F-150 works for V2H. The F-150 hooks into the CCS pins underneath the J1772 plug, and mostly likely uses the same digital signaling used for CCS, instead of the PWM signaling used for J1772.
Either way, the resistor across the PP/PE pins is mostly not for current capacity of the EVSE, but rather just the cable (which isn't normally an issue, as the cable is going to be rated as high or higher than the EVSE, and generally isn't detachable for J1772). This is relevant only insofar as the Type 2 connector in EU (etc.) use the same technology (including signaling).
Generally speaking, I'd expect CCS connectors to rely on an off-board inverter, as they can be built in a less weight conscious manner.
That's interesting that the Kia/Hyundai system uses J1772. I guess that means the output current is AC? Maybe easier to work with, in terms of wiring to the mains?
I wonder what the average power usage is for this target market. I just pulled up my (Tokyo-based, February, 2 person ap't) power bill and it comes out to 670W on average over the month.
People complain about lack of central heating, but I do wonder if that means that in the end lots of space is not being heated.
EDIT: According to [0], Household consumption on average in Japan hovers between 800W and ... 1200W. Of course bigger battery = more time, but 8 hours and 4 hours is definitely qualitatively different.
In Japan, Powerwall is also significantly cheaper than all Japanese maker batteries, last time I checked Powerwall's per-kWh price is only 1/5 of a Panasonic one. How could this happen?
Also Nissan Leaf price (3700kJPY/40kWh, without any grant) is closer to Powerwall (1200kJPY/13.5kWh, without any grant), despite Leaf come with full vehicle feature and V2H. I think Japan home battery market lacks competition.
Living in South Africa you need to plan around electricity issues.
Our coal plants are old and break down frequently and the new ones they built has design flaws so we have rotational blackouts lasting about 2.5 hours daily.
Bought a 1000W inverter with 12V deepcycle gel 100AH battery for the home office - it has a solar charger but we are in winter so that has to wait.
Ante-litteram I've made the very same system for myself: a small p.v. with 8kWh LiFeP BYD storage to have:
- AC coupled solar inverter functioning in case of an outage
- battery backup for critical loads (fridge, freezer, VMC, lights, computers) in the same case when there is no Sun shining
- a small generator to recharge in case of emergency
I feel the pain of a totally non-integrated IoT where devices can be barely commanded via ModBUS and only some can be monitored via ModBUS or MQTT, crappy flexibility and overall design etc... No vehicle-to-home integration so far (while a monodirectional to recharge an EV from p.v. depending on current availability is on sale from my battery inverter vendor) and an uncertain possible future expansion due to the crappy design EVEN if I choose "the most flexible and open solution on the market" (that's not their advertisement, that's what I've read in various forum) a Duch-centered brand with a light blue colored theme...
I still wait for:
- a damn open and common protocol to pilot IoT devices
- a damn realist design, witch means knowing how "a complete home" can be instead of try selling self-contained walled gardens crap
I doubt without public research that happen soon...
Orthogonal: Anker has been working on a 1.2 kWh portable battery that you can charge directly from regular outlets, or solar panels, as an alternative to generators. It's a pretty cool little device[1], I've been thinking about getting one. I hope they go bigger.
It's kind of hard to get that excited about the Anker given price to storage ratio. It's a fancy wrapper around a 100AH LiFePO4 battery. You can get a decent LifePO4 battery now for $399 [1]. I'm not sure the wrapper they have put around it is really worth the extra $1000 (total $1399, at least on Amazon). It's also weird their marketing material says charge to 80% in 1 hour [2] when it has a 300W max. (On Amazon, looks like it is actually 3.6 hours to 80%) [3]
I have one of the Anker batteries. It'll happily take in >1000W from an AC wall outlet to charge fully in ~1hr. It's 300W max DC input from solar (which is where that 3.6hr number comes from) or 100W max from a 12v car adapter.
Those other batteries you linked look like a potentially great deal for raw capacity, though there's something to be said for having a mostly portable package with thermal management and a bunch of different inputs and high-powered outputs.
Ok really dumb question but: how do you plug in a normal plug into a battery like this? I'm nervous about doing it wrong and then frying my musical equipment. The nice thing about the Anker is not having to worry about this.
My friends tried hooking up a car battery to an inverter and something went wrong (not sure what) and they fried 3k of musical equipment.
Yeah, as the poster notes, it's not bad. I've had a budget LifePO4 in use for over a year now with no issues. Can report back in 4 more years I suppose.
10 years ago I bought a cheap solar pump (~$100) rather than the standard priced ones at the time (~$1000) I got flack for buying Chinese made goods which were "surely crap". But that pump ran perfectly fine for about 8 years before it started slowing down and running at a reduced capacity.
Based on his reviews and recommendations, I did just purchase a 'cheap' 300ah Chinese battery off of Amazon (AmpereTime) to replace my 3 AGM batteries in my campervan. We will see how well it lasts...
These "solar generators" have been a thing for a couple years now; GoalZero sells 'em up to 1500W in most outdoor shops (I just bought a 500W "generator" + a 50W panel from REI), and their website has "home" versions in the multi-kW range.
I have a feeling these are gonna be a gamechanger for offgrid and nomadic living, especially with further improvements in capacity and price.
I'd love to see electric scooter / e-bike companies also adopt this technology too. My scooter has a 550Whr battery and I'd love to use it as a power station for some of my devices on the go.
I have a 1200mWh bike light that lets you charge stuff off it's battery, it's a life saver. I have used it to charge my phone and my rear lights in a pinch.
I am just remembering now that my e-bike has a USB port for charging off the battery too. I don't ride it much so I haven't used it yet, but I assume I could charge just about anything to full capacity off it.
What specific use case would you be using that for?
Besides something like camping where you can charge before you go and use it to keep some lower-power devices like cell phones and flashlights charged I can't really see where it'd be useful. It's not big enough for a job site or home backup power, and really just doesn't compete well against even much, much cheaper gasoline generators.
Lots of energy/climate change conscious people use < 10 kWh per day, 1 kWh battery buffer for small solar would do quite a lot, you'll know you can always charge ebikes and gadgets, etc.
The MX line is absurdly expensive. Not if you need a cordless jackhammer of course, but for most people.
The residential version of that product would be the EGO unit that can accept 4x 672wh batteries (56V*12ah). Those EGO 12ah are expensive, but still less than the MX XC406 at 6ah.
It’s an exciting time for battery tools.
EDIT: As compared to the MX or Anker units above, I have use for the EGO batteries while the power is on between lawn mower, snow blower, string trimmer, leaf blower, and chainsaw. So while the batteries can be thought of as consumable, I like that they don’t just sit in the corner forever.
Happy to see Anker went with the LiFePO4 batteries in the 757. They're definitely a chemistry I feel safer using in these bulk applications. Much more resistant to thermal runaway and they're not nearly as spicy if things do go wrong. Plus you can run them down to 0%.
In the long run it's likely that large household batteries like this for aiding in load balancing with solar/wind-centric electrical grids will become as ubiquitous as hot water heaters are.
Why would they be ubiquitous at the household level, not centralized as a "electric grid backup battery", like Australia's "big battery" https://victorianbigbattery.com.au/ ?
For hot water heaters, it's obvious that the water would arrive cold if it were boiled in a central location, but electricity can be transmit so efficiently that storing excess load will be much more efficient in centralized locations rather than at individual houses.
My guess is that this will be roughly as common as household generators, since both this and a generator are hedges against the electric grid failing more than anything else.
The equivalent water analogy would be everyone having their own household water cistern in case the water system failed, which I also think is vanishingly rare.
I think you would see both, but not quite ubiquitous like GP claimed unless in a region with trouble keeping their grid up. Utilities will do the cost-rational thing and deploy those batteries where beneficial, and households will adopt them as well because there is always the chance that an outage can happen between the big battery and your house. Or, if the entire system falls over for some reason, you can still be an island unto yourself with solar + batteries
re: hot water heaters - it should be noted that hot water and steam delivery systems exist and are quite effective(commonly derived from cogeneration sources) e.g.
LV circuits households connect to often don’t have a lot of spare capacity to absorb excess solar export in the day.
Voltage management is also a challenge with large amounts of solar export to the grid.
Solar systems are typically capped in the rate they can export to the grid for this reason.
Having a decent household battery to absorb solar output during the day and provide power at night could be a win-win both for households and power distributors.
For me I pay 20c (AUD) per kWH at night for electricity while selling electricity for 10c per kWH during the day. Using the electricity I generate at night instead potentially saves me 10c/KWH. At the right price I’d love one of these.
One reason is that overall power consumption needs, timing and priority are going to vary a lot household to household. For one household a power outage might be no problem, for another which depends on life support equipment, a power outage might be life threatening.
If you have centralized batteries, then the decisions about (a) how big they are (b) who they cut off if the battery is running out and (c) how the batteries impact the pricing of power are all made at the community level, which has value as a way to optimize the way an entire community draws from the power grid, but it lacks precision in how it helps individual households.
If you have localized batteries then people can choose (a) if they need batteries at all, (b) how many batteries they need and (c) how they want to use the batteries to offset their grid usage (some people might want to rely on batteries mainly for emergencies, others to aggressively charge and discharge based on different price levels throughout the day). It might be less efficient in aggregate but it is much more accurate in terms of delivering the benefits to the people that need them.
> Why would they be ubiquitous at the household level, not centralized as a "electric grid backup battery", like Australia's "big battery"?
Let's assume the existing electrical grid to be a somewhat fixed system that gets augmented from time to time here and there but does not get changed in fundamental parameters like voltage.
Then there's a certain grid capacity for transmitting power (watts) from central nodes (existing or former big power stations) to that large number of end nodes (homes) or in the opposite direction.
Let's also assume that the combined capacity of all the power lines which connect the homes to the grid massively exceeds the capacity of those (big) lines that connect the "central nodes" to the grid.
This means, that there exists a certain level in the hierarchy of the electrical grid (between central nodes and end nodes) where the lines do indeed match the capacity of all homes.
I'd think, these are the locations where you would build/connect centralized big batteries to the grid.
Because you could then take up all solar power from homes and at the same time you'd have some centralisation which would make building the facilities less expensive because of economy of scale.
Batteries also allow you to offset your solar use. You can fill the battery during the day and use the energy at night. That’s the most common use. Having one during a power outage is handy but shifting use is the primary use case.
8.7kWh at a somewhat high EU price yields somewhere between $2 and $3 a day. If this thing is about $6k, it should pay for itself within a year (if you have excess solar energy production, most contracts around here either don't pay anything for this, or trade at some 90%-ish discount).
Did I miss anything? I thought it would be 6 years at ~$1k saved per year, so I'm kind of waiting for prices to come down a fair bit more myself - also in the knowledge that batteries are rapidly improving now thanks to all the new players.
Regardless of the time to get ahead: Battery would make a great difference if your goal is to eliminate grid reliance and also to power an EV by solar only.
Whilst in summer a 6.6/5 system can produce 40kWh in a day, during winter months in Australia there really isn't too much sun - and what we get tends to be patchy. So being able to feed it into the battery would be great for avoiding grid use overall, and not to let bursts of sunshine go to waste.
You're sidestepping a lot of infrastructure difficulties by putting it at the household level. Your giant battery has to be put somewhere!
This is why I'm also pretty happy about solar, because you sidestep a lot of the NIMBY stuff that comes with building huge solar farms.
It's not at all ideal, though I don't know how inefficient it is (this model means that upgrades can happen gradually as well, instead of being multi-decade projects). But hey, you try building anything in most modern city bureaucracies filled with people who care about their real estate values.
I mean the pics of this make batteries look pretty small. Like smaller than a storage shed.
Sure it's only storing 8 hours, but the use cases described here are not bad. Imagine if we had 8 hours of battery storage across the world per household!
Australia has widespread usage of both. States are rolling out batteries to smooth supply disruptions while individuals are buying them to get the most out of their solar. Solar is so widespread in Australia that the rate to sell the power mid day is almost nothing. So you’d rather hold it and use it after sunset.
>The equivalent water analogy would be everyone having their own household water cistern in case the water system failed, which I also think is vanishingly rare.
I had a lot of power failures living in Canada, always due to the above-ground power delivery. I'm guessing this would also count for large parts of the US and the developing world. In Europe, I would bet on centralized solutions because the underground power lines rarely fail. But anywhere with above-ground power delivery, having a battery per household makes a lot of sense.
>Why would they be ubiquitous at the household level, not centralized as a "electric grid backup battery", like Australia's "big battery" https://victorianbigbattery.com.au/
For the US, there is little chance that such a centralized backup system would ever be built. The US doesn't really build big infrastructure things like this. They prefer everyone to have their own little version, at higher cost and less efficiency.
So about half the size of the battery in question. That is to say, Australia built a centralized battery almost twice the size. Their population is 25m. California’s is 40m.
There's a commercial incentive to build electric storage, if the price is right; you can buy when prices are low and sell when prices are high. Depending on the market regulations, prices are likely to get high during an outage, so there's your motivation for construction. Of course, siting is important too; if the big backup battery is right next to the big power plant, that helps for power plant outages, but doesn't help for wiring faults. And a battery facility that's not sized to power the grid island it finds itself in likely can't provide any power, unless the grid island has sufficient load shedding mechanisms, I'd guess.
If I want to build a modest cabin in a continental climate powered purely by solar+batteries, could I put the batteries underground for temperature stability?
I don't know much about this subject, but I'm scared of battery fires and I don't see anyone doing the underground thing, so I'm probably missing something.
A friend of mine lives off grid in Mexico. His setup is he built a small dedicated brick building adjacent to his parking area and solar array to contain any potential fire, deter any would be thieves, etc. Not quite as thermally stable as a cellar but a lot simpler and cheaper.
Hundreds of thousands of electric cars have been recalled due to risk of spontaneous battery fires with no damage, recalls initiated due to a dozen or two such spontaneous battery fires occurring in parked, unplugged vehicles. The batteries in almost all cases were manufactured by LG Chem, and the cause of the fires was several potential manufacturing defects, including torn anode tabs and folded separators, that could lead to a short circuit condition when the battery cell expanded and contracted, such as after charging the car. Recalls included the Chevy Bolt, Chevy Bolt EUV, Hyundai Kona EV, Smart ForTwo Electric, Chrysler Pacifica PHEV, and some VW ID.4s. LG Chem's stationary battery packs for home/solar use were also recalled for spontaneous fire risk.
On April 25, 1996, Ford Motor Company announced it would conduct one of the largest recalls for a safety-related defect in the history of the U.S. Department of Transportation. The recall covered approximately 7,900,000 Ford, Lincoln, and Mercury vehicles in the U.S. from model year 1988 through 1993 for a defect in the ignition switch causing the cars to catch ablaze spontaneously (NHTSA recall number 96V-071).
Although battery fires can easily reach 1500C, and involve reactions that generate oxygen, meaning that depriving the fire of oxygen isn't enough to put it out. The best you can typically do is just let it burn itself out. This works better when your EV is parked outside the home.
My concern would be about what would happen if the battery was sitting beside a house that caught on fire. That seems like a bad situation for firefighters.
Would it be much worse than a car with a full tank of gas in the garage or a few cans of diesel for a generator? A lot more potential energy in those than this battery even if fully charged.
AFAIU, you can stop a gas fire by removing oxygen (e.g. with fire extinguishing foam or a lot of water). Lithium batteries burning reaction provides its own oxygen supply so you can literally do nothing to extinguish the fire. It can burn even underwater.
I think I'd worry about getting rid of heat. You could do that with some pipes or something to couple the heat to the ground over a larger area. I don't think simply burying the batteries would be a good idea but it depends on the maximum heat output and conductivity of the ground.
"Underground" would mean a difficult maintenance. The batteries would still need to dissipate the heat which would be extra difficult in a closed compartment. So it will need proper venting, possibly fans.
I think the batteries would need to have a vent and you would want to be able to access them quickly in case of a fire. All I know for sure is that I would not want batteries attached directly to my house.
That's very Japanese, weatherproof and suitable for outside wall installation on a concrete wall. Tesla's Powerwall is intended for indoor installation. This is something to bolt on the wall alongside the outside part of the split air conditioner.
The temperature rating (-20C to 45C) seems decent but doesn't cover every clime. Tesla's powerwall is a better bet - indoors where you can worry less about external temperatures.
Officially recorded temperature is measured on managed environment, so real temperature could be higher. Still, it's rare to be over 45C, and it's "operating temperature" so maybe the battery can be just shutdown on rare very high temperature situation.
Each module is 3.2kWh. Can start with a small stack of 3 modules (9.6kWh), knowing this can be trivially upgraded 2.6x later without blowing out the cost.
Hard to know from this PR, but I'd assume you can get two or more of these if you need more storage or more output. IIRC, Tesla does 1-3 powerwall units in their standard sales process?
Storage capacity needs will vary based on the use, but over an hour of use seems like it would take care of a lot of people's needs in my seat of the pants estimate. And for many of those that don't have their needs met with 8.7kWh, 13.7kWh isn't going to do it either.
I was just talking to a relation about this, and he said Tesla's guy said he needs two Powerwalls to replace a generator in the event of power interruption.
Is that true, or a sales guy thing? I'm not sure and haven't investigated.
It depends on your relation's power usage, I'd imagine. I believe the spec is 5.5kW max output, which is probably insufficient if you've got any sort of large load. My well pump is rated for 30A @ 220V, so startup would likely overwhelm a single powerwall, and I think my air conditioners have similar startup needs (and I've got multiple units); we managed to trip the overcurrent protection on our 35 kW whole house generator during one of our early outages (it's unfortunately not connected to the well pump, overcurrent was just from using multiple heat pumps and washing/drying clothes; dryer heat is from propane. We had a nearly 3 day outage our first winter.
However, at my previous house, I didn't have any substantial electric loads, other than an electric water heater in an underused ADU, so 5.5kW would have been likely been fine, and our typical energy use was around 1kW, so we would have had several hours for service to be restored, which fit within the experienced outages.
So at full rated output power, 5.5kW, it can supply that for 12 minutes (60*1.1/5.5), right? That doesn't seem to be much capacity. Running at say 1kW output you aren't even going to run for an hour.
EDIT: The article must be b0rken. The spec sheet from Toyota says the storage unit capacity is 8.7kWh - where did the 1.1kWh get derived from?
The issue is that they say 1.1kWh, instead of 1.1kW, misleading you to believe that it can only output that much energy (total), rather than power (per hour).
Does anyone know of a home battery solution in India that does not cost more than the price of a small car?
I have read the per kWh price is around 9-12k inr but the retail price is around 22-40k per kWh which is just outrageous by the 2-3 retailers I know of.
Has anyone bought anything other than lead acid ? I am in the market for like 5-20 kWh if the per kWh actually goes down to sane levels.
Suppose 15k per kWh * 20 =300k which is quite reasonable if we get 5-10 year warranty
If you have the space I think you would be better off using lead acid batteries or wait another 5-10 years. Though lithium based battery production costs are still falling 10-20% a year the demand even at current prices is high enough that we are not getting better prices at consumer wholesale let alone retail. So far to me it seems the battery demand from electric car manufacturers as well as grid scale battery installations is rising faster than the supply. With the current gas and oil prices the demand is going to increase even faster where as supply will still take years to catch up.
i understand that but the lead acid vs lithium pricing is complicated to say the least. here is an example i got recently.
12v 4 qty 200 Ah =9600 wh with usable around half so 5kwh. it would cost me INR 100,000 almost with a 5 year warranty. this is lead acid one
lithium i got a quote for 48v 100ah = 110,000 INR for 3-5 years warranty.
the seller is pushing me to buy the lithium battery but the pricing is not competitive enough imo. they are charging me a huge markup so unless i buy from their suppliers, i dont see the benefit of paying he dealer a huge markup for no "addition" of theirs.
this scooter is selling for the same 100,000 with a 4.5 kwh battery. i know its 72v vs 48v but just saying they are giving the same battery + entire scooter so the battery should definitely not cost this much
No, the energy density is poor. Gravitational potential energy depends on mass and height (mass * gravitational acceleration * height = energy in joules). If your whole house went up and down 10 meters it would store just a handful of kWh, maybe 1 to 10 depending on the mass of your house.
I am just about to have a 3 phase 30kva diesel generator installed on our farm for backup power. Multiple people had asked me, why not get a big battery? I honestly hadn't thought it was a viable option. Not sure. I want to power two houses in middle of summer or winter (-2 to 45 degrees C range). Power outages can last up to 24hr.
If you plan on keeping the same quality of life/not thinking about what kind of power you're using, go with the generator.
If you're ready to make some sacrifices/be a lot more conscientious with energy use, take the battery capacity you think you need and then double it.
Air conditioning, heating, stuff like microwaves and electric cookers, dryers, etc consume an absolute ton of power, and I imagine you'd have even more high-power appliances on a farm.
Having watched a video or two, I would not want that battery to be within twenty feet of my house. Just like I keep the BBQ away from the house. Rather not unnecessarily increase the risk of fire.
Come to think about it, lining one’s garage with a double layer of overlapping gyproc firewall might be wise. EVs burn hot.
Many comments here are concerned about the flammability of lithium, though in a stationary form, cooling and ignition are pre-emptabe via water or a phase change encasing.
The way especially Americans talk about backup battery solutions confuses me. The Tesla Powerwall is spoken of as though it were a particularly unique innovation, and it's apparently news for Toyota to unveil an...8.7kWh battery. They just seem like par for the course to me, on the way too expensive side even.
Then again most of the products that have existed in this space/have been deployed in the developing world are from India and China, so it's perhaps not surprising that Westerners haven't been drooling over those.
That’s an impossible question to answer without defining what dead means. It’s going to degrade over a very long time with no clear point that marks end of life.
As it doesn't need to move, it can sit there in an unused space and be really heavy. Lead Acid Batteries are a very good fit here (traditionally used as the 12V battery in cars).
In Australia you can buy a 12V 42AH (amp-hour) battery for ~$150AUD or $100USD. 20 of these will give you 10kWh @ 240VDC.
Couple this with a 6kW solar system and you'd be almost entirely free from grid electricity, especially in summer.
You can individually test out the batteries and swap out bad ones. The batteries themselves typically last >5years in a car and I imagine much longer at home where they aren't exposed to high engine temps and large continuous current discharges (engine cranking on start up).