Toyota unveils 8.7 kWh battery for residential applications
pv-magazine.com
pv-magazine.com
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).
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.
(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.
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).
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.
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.
This guy also has a lot of educational videos: https://www.youtube.com/c/WillProwse
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.
Am I missing something?
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.
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)
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.
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.
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.
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!)
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.
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.
[0]https://www.optimabatteries.com/optima-product-categories/ba...
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?
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
I have this, just haven’t installed it yet. $5500 for a half rack.
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.
[1]: https://batteryuniversity.com/article/bu-804-how-to-prolong-...
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.
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.
LiFePO4 is a huge improvement over lead acid.
I ask because I have a powerwall under the floor where i'm sitting right now and zero hesitation about it.
Indeed, with my ~6.5kw nominal solar, I am essentially net neutral.
The car in my driveway has a lithium battery 5x the size and hits 50 degrees during this heat wave. It also charges at about 3x the rate.
So the relatively cool crawlspace seems like a totally normal place to discharge at 5kw?
If you go with another chemistry, I think you'll find that cycling from 100% to 0-20% daily will not last for many years..
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.
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.
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.
Edit: replaced * with × to fix formatting
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.
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.
Here's the datasheet for a GC2 form factor Trojan T105-RE from about a decade ago (I've got a 6 year old pack in my office): https://www.trojanbattery.com/pdf/datasheets/T105RE_TrojanRE...
Notice that it's rated for about 700 cycles, to 100% DoD. And about 4000 cycles at 20% DoD.
Lead has many advantages for stationary storage, and they're not the same batteries you found 40 years ago.
However, I think a lot of people with electric cars and attached garages don't think twice about it.
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.
It sounds to me like you're asking for a nickel-iron battery.
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.
lifepo4 is where it's at.
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.
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.
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.
Because even Toyota found the Lithium works better for that application.
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.
(The amount needed is also relevant, I'm not sure exactly how much lithium is in lithium ion batteries and how much nickel is NiMH.)
I mean, definitely not in the news as much as Tesla...
2018 https://money.cnn.com/2018/09/05/news/companies/toyota-prius...
2019 https://www.yahoo.com/entertainment/toyota-prius-catches-fir...
Customers don't report issues if you force them to sign NDAs to get their cars fixed under warranty.
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.
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.
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.
OT: in Europe, a thiol is added to natural gas to give it a distinctive smell. Isn't the same done in the US?
The problem is fire safety, if the house is on fire the lithium battery is going to make it much worse. Controller ofcourse does not help there
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)
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.
For stationary applications why not.
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.
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.
What does this mean? My naive reading would presume a stake in the ground?
For fun, put a nail in dirt. See how long it lasts.
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.
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.
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.
[1]: https://aktif.net/en/types-of-earthing-systems/#IT_System
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 )
There may be no earth spike, but if earth connects to a copper pipe going into the ground, you'd expect them to be at the same potential.
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.
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.
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.
Maybe mine some bitcoins during summer? ;)
Also, I bought the panels to reduce carbon emissions, and would rather sell the power back.
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.)
> Some sort of cheap long term storage would really help a lot.
Run a still to make ethanol from waste biomass. Store it (don't drink it!!) and use it to fuel a generator in the winter.
I'm only half joking.
https://www.car-engineer.com/adapting-an-engine-to-ethanol-f...
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.
I mean yeah, but so would Mr. Fusion.
The eF150 gives you a couple days. The Prius is a better solution if you really need backup power.
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.
1. https://www.texastribune.org/2021/02/19/texas-emergency-comm...
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.)
https://www.plugoutpower.com/inverters
> unplug them and go refuel the car if needed
Just like standalone generators, this is a tough point. Fuel can become hard to source during a an outage > 5-7 days.
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.
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.
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.
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.
We heat and cook using natural gas.
The biggest consumer are the same here. Dishwasher and laundry.
All that stuff gives one great insights into what a kWh is (how much energy), where you use the most energy etc. I love it.
[0]: https://www.home-assistant.io/blog/2021/08/04/home-energy-ma...
[1]: https://www.zuidwijk.com/product/slimmelezer/
[2]: https://shelly.cloud/products/shelly-plug-s-smart-home-autom...
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.
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.
Do you mind shared where this is?
I also made a quick price comparison between the US and here:
- electricity? US: 0.14€/kWh [2]; here: ~0.30€/kWh [0]
- diesel? US: 1.40€/l [3]; here: 2.19€/l [4]
- gasoline? US: 1.26€/l [5]; here: 2.39€/l [4]
- natural gas? US: 0.44€/m³ [6]; here: 1.16€/m³ [7]
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.
[1] https://www.vlaanderen.be/statistiek-vlaanderen/inkomen-en-a...
[2] https://www.eia.gov/electricity/monthly/epm_table_grapher.ph...
[3] https://www.statista.com/statistics/204169/retail-prices-of-...
[4] https://carbu.com/belgie/index.php/officieleprijs
[5] https://gasprices.aaa.com/state-gas-price-averages/
Unless you meant 100 kWh/day, which would be doable, but I think only with geothermal.
2000 sqft is 185m2 which is a mansion by my standards though :)
And 60 kWh/day is still enormous.
I have 2800 sq ft house and use around 30-35 kWh/day in summer. 60kWh/day is high but not outrageously high.
Average electricity cost in Finland is €0.184/kWh.
[1] https://www.finnwards.com/living-in-finland/how-much-do-home...
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).
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.
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.
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.
Not much even in an efficient house.
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.
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).
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.
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.
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.
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.
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...
Also the not-produced platinum model you reference will sell for 150k+ so the price comparison isn't really valid either.
Lastly, home batteries have the potential to pay for themselves over time, making the economic models radically different.
I'm curious to see how thermal management is done. 45 C is not _that_ hot for a black box in the [insert warm place] heat during summer.
I'm also curious if they were able to use the casement as a heatsink in itself
If you have a garage integrated into the home, I guess it might be undesirable.
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.
-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.
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.
https://www.nist.gov/how-do-you-measure-it/how-do-you-measur...:
“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.
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.
The -20C limit could hit more areas, but if placed indoors I guess most should also be fine with that.
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.
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 :(
Private transportation is largely unsustainable anyways.
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.
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.
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.
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.
https://www-toyota-co-jp.translate.goog/homebattery/?_x_tr_s...
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 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
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.
Power: Toyota: 5.5 kW, Powerwall: 9.6 kW (off-grid).
Energy Storage: Toyota: 8.7 kWh, Powerwall: 13.5 kWh.
If you estimate an average power use of 2kW while off-grid, then the Powerwall gets you 6.7 hours, and the Toyota gets you 4.3 hours of power.
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.
[0]: https://www.statista.com/statistics/1291424/japan-energy-con...
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.
- 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...
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.
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.
[1] https://amzn.to/3zzt5KY [2] https://cdn.shopify.com/s/files/1/0517/6767/3016/files/KSP.j... [3] https://amzn.to/3xoGWBp
tl;dr: It isn't totally horrible, but you get what you pay for in this case.
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.
¯\_(ツ)_/¯
https://www.youtube.com/watch?v=KvCdo0cs99w
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...
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.
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.
Greenworks and TORO have a little 300W inverter that you can plug their lawnmower/yard equipment batteries into and use as a portable power back.
I have a feeling these are gonna be a gamechanger for offgrid and nomadic living, especially with further improvements in capacity and price.
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.
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.
8.7kWh is not a great amount, but if the price was right it could make a lot of sense. Two of those units ... now I'm interested!
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.
What is improving - energy density, price, need for rare materials?
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.
My point stands: this won’t catch on in the US.
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.
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.
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.
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!
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.
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.
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.
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.
The stove in your cabin (and you) are a far greater risk than a battery would be.
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).
A stable 75F might be better but I'd rather have stable 50F over unstable 75F.
My whole point is that cars are more demanding than houses.
So the house battery can tolerate a moderately lower temperature while meeting baseline performance.
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.
Powerwalls can be installed outdoors. Mine are installed on the exterior of my home.
I have seen discussions of local codes in parts of the country requiring them to be installed outside due to perceived fire risk.
> https://www.reuters.com/world/asia-pacific/fire-breaks-out-t...
https://www.acsolarwarehouse.com/news/sungrow-battery-and-hy...
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.
I would bet this will be priced better per kWh because there's less of a status symbol to it, but 8.7 is a lot smaller.
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.
Is that true, or a sales guy thing? I'm not sure and haven't investigated.
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.
Edit: nevermind
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 1.1 kW number is the power of the EV charging adapter for the system.
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
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.
to put this lithium into perspective, https://okayaev.com/faast/
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
How would they compare to the other options like lithium and lead batteries?
[1] - https://www.bbc.com/future/article/20220511-can-gravity-batt...
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.
You would increase the size of the batteries to give enough capacity to last through a power cut.
(Your climate is outside what I'm familiar with, so I don't have any instinct for the economics.)
Come to think about it, lining one’s garage with a double layer of overlapping gyproc firewall might be wise. EVs burn hot.
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.