Why your outdoorsy friend suddenly has a gummy bear power bank

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258 points arnon | 1 comments | 21 Sep 25 12:31 UTC | HN request time: 0.231s | source

https://archive.ph/1G2Ut

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cenamus ◴[21 Sep 25 13:07 UTC] No.45322381[source]▶

20Ah for 23 bucks? Seems like it's almost too good to be true. Wouldn't surprise me if it was just half that, would explain the price and weight.

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thegrim33 ◴[21 Sep 25 14:56 UTC] No.45323306[source]▶

>>45322381 #

Man it drives me crazy when people/products use Ah instead of Wh as a way to specify battery "capability".

Without knowing more details about the battery, "20Ah" alone does not convey enough information to determine how long the battery could power a given load for. If I need to power a 100 watt lightbulb, will a 20Ah battery power it for an hour? 10 hours? 10 days? No way to know.

Wh is the unit of stored energy, Wh is what I want to see. Even the official Amazon product page for it doesn't list a Wh figure.

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esperent ◴[21 Sep 25 16:13 UTC] No.45323988[source]▶

>>45323306 #

Isn't that 20Ah figure always relative to the internal voltage of the lithium batteries, 3.7v? At least that's what I always assumed.

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1. rcxdude ◴[21 Sep 25 20:37 UTC] No.45326411[source]▶

>>45323988 #

Not necessarily, no. If you have multiple batteries in series for a higher voltage pack, then it'll be less for the same amount of energy stored. But then the marketing for these packs will happily abuse the units to get the biggest numbers.

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