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Comment by Octoth0rpe | Hacker News Reader

From the article:

> The battery they built has a 500-mile range

Cool!

> ...and can be recharged more than 1000 times.

Wait, what? That seems like a very small number to quote. I mean, I assume when a company quotes a number like that, the real number isn't _much_ higher than the number they do quote. Let's say, 1200 or so. I'd really like some clarity on that number. If 'charging' in this context means going from say 80% -> 100%, That's less than 4 years if you charge it that much every every night, which may be very close to typical. What happens after 1000 charges? I assume at that point there is some loss of capacity as is typical, but it'd be helpful to know how much loss.

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If that's 1000 full charge-discharge cycles, that'd be completely acceptable (assuming that the usable capacity is still close to 100% at the end of the lifespan) for a car which typically has a lifespan of 150,000 miles or so.

(1000 * 500 miles / charge) = 500,000 miles

Agreed. It'd be nice if we could have some kind of confirmation.

I'm not an expert on the issue, but that's a good number.

The original article states it's a cycle life of 1000 charges, that means full charges, say charging from 90% to 100% doesn't count as a full charge. These batteries are tested with 0->100 charges, but other factors affect battery life, like temperature and charging rate. After the 1000 cycles the battery isn't dead, it will just hold partial charge, basically degrading partially over time each discharge. It's basically saying "After 1000 full charges, the battery will only retain 80% of the original battery capacity".

IIRC my pixel 3a has LiPo battery and is rated for 300 cycles and from what I can tell lithium ion usually has a cycle life of ~500.

edit: Adding link to original article https://news.samsung.com/global/samsung-presents-groundbreak...

> What happens after 1000 charges?

Usually the end-of-life for traction batteries is specified at 80% of original charge (80% state of health), after that they're recycled as industrial energy storage for grids etc.

But with articles such as these, claiming breakthroughs and whatnot, it's always good to be extra suspicious and verify that they're using the same assumptions.

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