Trying the following might reset the battery:
- Ensure Evo is not connected to power
- Hold power button down
- Continue to hold power button down as you plug Evo into power using a micro USB charge cable (you might have to hold power button down for up to 20 seconds)
- Evo should be going through a series of light changes. Continue to hold button down until lights begin to pulse indicating that the battery is charging (you might have to hold power button down for up to 20 seconds)
- Leave Evo connected to power until front lights turn solid green
If this isn't immediately successful, remove the micro USB charge cable from power, plug the micro USB charge cable back into power, and try again.