Testing the reassembled Powermonkey under various loads proves instructive:
The relatively low capacity at 100 mA (black) shows that the boost converter isn’t particularly efficient; the discharge time is long enough that power loss in the booster outweighs the cell’s higher capacity at lower loads.
Surprisingly, the voltage drops to 4.5 V at 500 mA, which is what you should get from a typical USB port. If the device you’re charging expects the nominal 5 V at 500 mA, it will be sorely disappointed. Admittedly, that’s only 10% low, but …
The booster produces only 4.0 V at 1 A, with odd bumps as the cell discharges. Huh?
I know for a fact that my 1.8 A @ 5.0 V Kindle Fire doesn’t even notice it’s plugged into the Powermonkey. The voltage is probably too low to trigger the “External Power, Ahoy!” signal.
Bottom line: it’s not clear this thing actually works for contemporary devices. Maybe newer Powermonkey products behave better?
The Smell of Molten Projects in the Morning 
Comments
3 responses to “Powermonkey Battery Capacity”
hack dat mcu and give it more BOOST less BUCK
speaking of bucks, hopefully it was dirty cheapness…
Might be a cheap chinese PWM, smaller resistor on an input and Voila’
>:-)
I could fiddle with it, but it’d require dismantling the PCB and scraping off all the foam tape goo… and I doubt it’s worth that much effort. [mutter / grumble]