Why your outdoorsy friend suddenly has a gummy bear power bank

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.

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.

If your 100W light bulb is a USB bulb running at 5V (to make the math a bit easier), with 20 Ah you’ll get 100Wh, ergo it’ll run your bulb for a hour. You just need to specify the voltage. There are numerous online calculators to do this math for you.

https://www.inchcalculator.com/ah-to-wh-calculator/

Watt-hours won’t save you, because we don’t know what voltage your bulb needs. Don’t assume it’s 120/240V.