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by kazinator 181 days ago
That's only a valid concept in some embedded engineering case, where a certain capacity is required, and double that amount is provisioned to account for degradation.

Few consumers think this way. Something doesn't have double the capacity that it has; the capacity is the capacity, and the decline looks bad.
1 comments
ryukoposting 181 days ago
The whole idea of the embedded part is that you make the degredation invisible to the consumer for as long as possible. From the factory, only charge up to ~4.07 Volts or thereabouts. Every N cycles, add 0.01 V to the threshold. Your phone probably already does something like this.

But yeah, 20% degredation in 100 cycles is atrocious. No amount of firmware shenanigans will be able to paper over that, not in any regular consumer product at least.

I can still think of use cases, though. Reserve power sources that aren't meant to be cycled daily, where smallness is valuable. Those little car jumper packs, for example. If there was a UPS close to the size of a regular power strip, I'd buy a few.

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hinkley 181 days ago
Engineering is compromise though. If you can make a hybrid that loses 5% at 100 but still retains 500wh/l you’re in good shape.

There was someone working on a membrane a while back that’s pretty good at diffusing the lithium transfer in a way that reduces dendrite formation substantially, for instance. That’ll drop your volumetric advantage and likely your max discharge and charge rate a bit but would fix a lot of other problems in the bargain.

I’m not saying that the solution, but there is a palette of tools you can mix and match and that may be one of them.

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joecool1029 181 days ago
> Your phone probably already does something like this.

It most certainly does not. Most devices track battery health % (last full capacity divided by design capacity) and the gauge just presents state of charge (current capacity/lastfull)

The better phone charge threshold systems measure usage and keep the phone in the 30-80% soc range as often as possible.

Voltage drops faster on old cells as they age so you need a coulomb counter. Only extremely shit designs guess soc based on voltage alone.

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