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Comment by sundvor | Hacker News Reader

Absolutely. As an EV owner who wants to keep his car for at least ten years, it doesn't make sense to me to dull out the high capacity batteries to support the grid. It seems to me that it would be better to use recycled batteries for home PV storage etc.

I'm not too obsessed but it was easy enough to look up the data on what charge states result in the least loss of range over time.

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What if your car battery had a chemistry that could sustain ~10000 cycles if well handled, and aging in general was a bigger issue than cycle degradation?

We’re approaching this with the recent LFP generations.

LiFePO4 batteries I bought in 2017 were rated for 4000 cycles of 80% depth of discharge. Shallower discharge counted as partial cycles. Even at such a heavy use, that's almost 11 years of heavy use every single day -- after which the battery still continues to operate just fine, with slightly lower capacity.

People are afraid of actually using their batteries, and engaging in FUD about their aging. It's weird.

> People are afraid of actually using their batteries, and engaging in FUD about their aging. It's weird.

And some of the same people change cars a year later (talking about EVs, of course — because it doesn't have HW4, 4680s, etc.). Some of it is human nature, though.

What if you were reimbursed 5x your meter price for the power you sell back to the grid? With electricity spot market, this sort of money is around and should of course go to the vehicle owners, at least a big share of it. Only a fraction of the total battery capacity would be involved in this scheme and with light load, so the battery degradation would not be that big. And this would not happen daily.

> With electricity spot market, this sort of money is around

This happens precisely because of supply-demand - peak dispatchable bulk generation is more expensive. VtG brings a lot of cheap supply bringing prices down and causes balancing stress on distribution grid, increasing distribution costs. 5x sounds like an absolute pipe dream

The price level would be determined in the market of course, maybe most vehicle owners would be ready to participate with lower reimbursement ratio. Anyway, I doubt this would cause a lot of stress to the distribution grid as the vehicle batteries are probably closer to the loads than the large scale power stations. The EVs powering neighbourdhood ACs and so on. So at least the distribution transformers could easily see lower load than without V2G.

or not just recycled EV batteries, but alternative batteries that don't need to have good weight ratios. PV storage should maximize the cost-efficiency, since that is the determining factor, not weight ratios like in a car would optimize for.

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