don't worry... own a lot more bigger lipos than that tiny 1100mAh GoPro bugger, puffed only a few past 18yrs
methink there must is some current-limiting by the GoPro circuitry - it doesn't charge any
noticeably faster off a iPad 10W wallwart (2.1A max) vs a standard iPhone 1.0A unit.
Both takes ~2hr for the red light to go out from (what camera thinks is) dead flat, that's barely 0.5C.
Charged it once from partially charged (2bars on LCD)... took about an hr for red light to go off.
Lipo charge routine is highly dependant on cell voltage anyways, since current/capacity is preset.
Read somewhere some say it keeps charging for a bit after red light goes out, can't confirm
until i've rigged up a suitable USB power source with ammeter to tell what its really doing.
(Sony Cybershot camera's manual does write that though; & Vaio got 2 user-selectable cutoffs 80% & 50% too)
ok you've got me curious... HD2 was plugged in since dinnertime & should be fullycharged by now,
so i yanked out the lipo & probed it --> measured only 4.06V.
Wow that's not even close to 4.20V.
I'd expect @ 4.06V it'll still be in constant current charging stage, then just cutoff.
Be simpler to implement than a Reducing Voltage stage, although that's not rocketscience either.
Guessing that GP is (litigious!) US-based, yeah they probably plan to play it real safe
Will wait till i get a few more batteries before any further probing;
be interesting to see if offboard chargers will pump them any higher vs runtime.
For the record currently getting 123mins recording from onboard charging.
@OP: sorry for offtopic hijack; yeah that iPad 2100mAh wallwart is what i use more often that not