10 - 30 minuten
Like so many, I'd been experiencing rapid battery drain seemingly after updating to iOS7.x.x. I tried all the OS tweaks suggested online, and did the clean reinstall with help from Apple Support. These worked to a degree, or temporarily, but did not really solver the problem, so i decide to install a new battery from ifixit.
This was my second iPhone repair, first was replacing a cracked 3GS screen, so replacing a battery seemed pretty straight forward--and it was! Taking the phone apart was quick and easy, but getting it all back together was slower due to aligning the pressure switch and handling the very tiny screws. This takes a careful, zen-like approach to keep the mind calm and the hands steady.
I should have done this sooner instead of spending all that energy on iOS settings tweaks. My battery easily last +24 hours and seldom drops below 40% now. This should have been an obvious first step:
--my 4S was beyond it's 2-year Apple Care coverage
--the old battery had been constantly used for 30 months
--my previous 3GS experienced similar battery decline at the 2-year mark
--iOS setting tweaks had minimal effect.
So try this fix!
Durning all my install and repair work I use a soft mirco-fiber cloth as my work surface so the tiny screws don't bounce away if dropped.