My issue is somewhat different but perhaps someone can help...
My battery life is about 15 minutes if I use the phone, and several hours if I don't...
One might assume it was a batter problem but it's not... Here's the logic...
1) Charge to 100% ...
2) Disconnect from computer and use any apps, it will power down in a about 10 to 15 few minutes...
3) Connect to the usb to charge and after about one or two minutes it's fully charged...
This suggested there is a fault in the phones voltage checking mechanism, as you can't charge a battery from 0 to 100% in 60 seconds... Also, to discharge from 100% to 0 in ten minutes would result in substantial heat but the phone remains cold...
Note if I just unplug after charging and don't use the phone, it will indicate fully charged for many hours... If I then use it, I will get a few minutes and it will power off again... Charging the batter again will only take 2 or 3 minutes... suggesting the battery was probably partially charged t begin with...