Battery problem, try this.
With the phone in the on position.
Fully charge the battery with the phone on... (until the led turns green.)
Once the led turns green, unplug the charger until the led goes off.
After the led goes off, plug the charger back in. When the led turns green , power off the phone.
now.... with the phone fully powered off...
1. Unplug the charger.
2. Wait until led goes off.
3. Plug charger back in until the led turns green. When it turns green, unplug the charger again and go to step 1.
4. repeat steps 1 and 3, 10 times. This may take anywhere from 30 seconds to 30 mins per cycle. Typically only about 1 minute. though.
DO NOT DRAIN THE BATTERY. The goal is not to empty the battery and recharge like ni-cads (those have memory, these don't). These are lithiums, so we need to do the opposite...