Phone will not operate unless charger connected

[hengis]

My HTC M9 requires the charger to be connected and the battery indicator to show 100% Otherwise if I switch on without the charger connected the phone gose into restart mode. Any suggestions would be appreciated

 

[ocnbrze]

looks like time for either a new battery or new phone.

 

[Hadron]

Yes, your battery is completely shot. It sounds like the battery has reached the point where it is only able to deliver the voltage the phone needs when it is plugged into the charger (the phone itself cannot run off the charger: the charger charges the battery and the phone runs off the battery). The 2 options @ocnbrze gives you really are the only options you have.

 

[Dannydet]

New battery or new phone....
You make the choice