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Comment by mrfusion | Hacker News Reader

But if the Tesla car battery can only handle 1000 charge/discharge cycles, how is a home battery viable? Wouldn't it only last for three years or so?

(Maybe I'm wrong about the number of cycles?)

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Some companies have battery technology they believe is good for 10,000 [1] or even 16,000 [2] cycles until it reaches 80% of its initial capacity.

On the other hand, some batteries on the market show substantial capacity loss after just 300 cycles [3].

Needless to say, the product that lasts 50 times longer costs quite a bit more - and they're bigger and heavier to boot. For stationary power storage, you don't care if they're big and heavy, but for transport applications you do.

[1] https://www.toshiba.com/tic/datafiles/Battery_Energy_Storage... [2] http://www.altairnano.com/wp-content/uploads/2013/01/60Ah-Da... [3] http://industrial.panasonic.com/www-data/pdf2/ACA4000/ACA400...

So you think they'll build these to have more cycles?

I think they'll build them so they make economic sense to customers. I think that would probably mean having more than 1000 cycles, but it could mean being really cheap, or some sort of lease/periodic replacement deal, or something like that.

If you magically made the Tesla S battery last 1000 cycles, it could make $12 per cycle, grossing you $12,000 over its life.

The replacement cost of a Tesla S battery is $30,000.

The car tech has to worry about density and being charged really quickly. A big home battery should be able to make different tradeoffs including more cycles. Also, it lasts a lot longer if you're not discharging it all the way.

If they could make it last as long as solar cells are described to last, 20 years or so, then I'd consider it.

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