Chosen Solution
why does my phone shut off before the replacement battery is depleted? Starting the day I replaced the battery my 3gs iphone will shut completely down like the battery is dead. When I plug the charger in it comes back on, but the battery immediately shows about half charged.
Most iP* devices will auto shut down around 10% (I believe). If your not getting a full charge the battery will probably need to be replaced. I would also use an AC charger, it has more power and faster than connecting to your computer via USB.
I am facing the same problem of sudden shutoff of iPhone 3GS at sufficient battery level upto 60% is there. Phone doesn’t start without plug into charger or computer. Cannot figure out but suspect the root cause of software update to ios 5.1.1 the only thing I changed in phone, or may be any other app.
