My phone was very unstable when using the spare battery All 2-3h it depends on irretrievably and to hard reboot happens first nothing more (screen stops in its current state when vibration is performed, this is still a few seconds more) Most seemed to occur with heavier loads, VLT. supplies the battery is not enough current, etc.
Maybe I got a Monday product, am not in any case satisfied.
For permanent swap it is the P880 eh 'not because you want the back cover open / close hardly frequent, therefore is a benefit as emergency battery also does not make much sense.
