A car battery should be enough.

EV battery capacity is expected to grow to 100kWh.

People will park them at home every night, and probably somewhere with a charging point during the day.

Smart house energy management should be able to pick up on that usage pattern and use the car battery for the house while making sure the car is kept ready for use.

In the same way that wifi/mobile/satellite comms can keep us "always connected", the changes in power generation and storage are going to keep us "fully charged".

	▲	heresie-dabord a day ago \| parent \| next [-]
		A house might use 20 to 30 kWh each day. Modern EVs have enough battery capacity to power some appliances for many days. Vehicle-to-load ("V2L") is currently offered in vehicles made by Hyundai, Ford, GM, Volkswagen, Volvo, Mitsubishi and Nissan (the new LEAF). Vehicle-to-grid (V2G) is more ambitious. https://en.wikipedia.org/wiki/Vehicle-to-grid
	▲	nxm a day ago \| parent \| prev [-]
		The cost here is premature degradation of the battery due to additional charge/discharge cycles.

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Jeremy1026 a day ago | parent | prev | next [-]

Not for the thought experiment of "I want my summer excess to power my winter usage" posed by the author.

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KaiserPro a day ago | parent | prev | next [-]

In the UK you'd need a class D "loi-sonce" to be able to pull the shipping container sized battery trailer for that to work.

However, if you were wanting to use pure lead acid batteries for your house, because you'd be doing slow charge/discharge you'd probably be able to get away with just 1100 130ah lead acid car batteries.

I mean you'd be optimising for peak current, which isn't what you'd want. However it could be interesting to see what happens when you have ~500mega Amps at 48v. (24Mw would heat your radiators up pretty quick. )

for lithium, then you'd need 12-14 secondhand tesla/polstar batteries, which if they caught fire, might be a challenge to contain.

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giveita a day ago | parent | next [-]

1100 car batteries might cost maybe $100-$200k and need replacing every 4 years.

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mnw21cam a day ago | parent | next [-]

Lead-acid car batteries are designed for high short-term current supply, for starting engines, not longevity. You can buy deep-cycle lead-acid batteries that last much longer, on the order of over ten years. Moreover, lead-acid batteries wear out when you discharge them too much more than by time elapsed, so taking good care of them can make them last even longer. Lead-acid batteries are great for standby storage, where you normally only discharge them a small amount between charging, but then need to use the whole capacity every now and again (for instance if you have a few dull days).

LiFePO3 batteries don't take as much wear from cycling, so they usually wear out from time elapsed instead of over-use. It's economically sensible to cycle LiFePO3 batteries as frequently as possible to get as much "benefit" out of the investment. They're great for time-shifting energy production by charging them at a cheap time of day and discharging them when you need the energy at an expensive time of day.

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bot403 a day ago | parent | prev [-]

Did you take into account that lead acid batteries are recommended to only be discharged to 50% especially when used for solar ? If not thats now 2200 batteries and $200-$400K.

	▲	KaiserPro a day ago \| parent [-]
		I eyeballed the maths on that. 1100 * 12v*130ah should give you a .7mwh of leeway to not do "deep" discharge.

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Ylpertnodi a day ago | parent | prev [-]

"loi-sonce", would be better "loi-sunse". That 'o' is very jarring.

	▲	KaiserPro a day ago \| parent [-]
		I was going for beeeergminghum, but for cockney, the o is indeed jarring

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joemazerino a day ago | parent | prev [-]

Not even close. A typical electric split will take 12a to maintain and that is just the heating/cooling system. Car batteries are meant for starts, not maintenance flow.