Mostly because I have the technology, here’s a battery rundown test for the (guts of the) Alpatronix iPhone case:
Bypassing the entire battery controller doesn’t tell you when it thinks the lights should go out, but does give an indication of the raw battery capacity:
Multiplying the nominal 3.7 V by the nominal 5 A·hr capacity says it should have a nominal 18.5 W·hr capacity at some unrealistically low discharge rate. Given that I found it at the end of the driveway with no provenance, I didn’t expect much.
To my utter astonishment, it delivered 17 W·hr at 500 mA!
It really ought to be good for something …