Why your outdoorsy friend suddenly has a gummy bear power bank

(www.theverge.com)

258 points arnon | 1 comments | 21 Sep 25 12:31 UTC | HN request time: 0.207s | source

https://archive.ph/1G2Ut

Show context

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.

replies(8): >>45322494 #>>45322612 #>>45322781 #>>45322945 #>>45323050 #>>45323306 #>>45326979 #>>45328472 #

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.

replies(8): >>45323988 #>>45324108 #>>45324359 #>>45327092 #>>45327383 #>>45327422 #>>45327424 #>>45327597 #

cenamus ◴[21 Sep 25 16:44 UTC] No.45324359[source]▶

>>45323306 #

Yeah, but pretty much every power bank uses lithium ion batteries (or used to, at least), so you use 3.7 average volts.

replies(2): >>45326332 #>>45326347 #

1. hedora ◴[21 Sep 25 20:26 UTC] No.45326332[source]▶

>>45324359 #

If you want to quadruple your amp hours without modifying the hardware, just treat 25% of the voltage gradient of each battery as your unit of measurement.

Alternatively, since this is USB-C, and we assume the marketing copy is honest, use the max voltage USB-C can deliver: 20v.

So, draw 20V from this device and measure the amp hours it outputs.

Wh is really the only sane way to go.

↑