Would like to ensure that a mobile phone is always charged, without requiring manual intervention (s.a. disconnect/reconnect charger, switch on/off charger etc.). One thought is to put the phone permanently, with it's wall-wart charger connected to AC mains, always. How feasible / practical is this, and are there better approaches ?
Note that, I am unable to make changes to the phone, because it is an off-the-shelf, commercial phone, but okay to make changes to the circuit of mobile charger.
Edited: This is not a specific phone model I am talking about, but potentially a phone I'd buy, for a very specific purpose. This might be lower-end Android smartphone. The phone would be left in an unattended / remote property, and serve as a fixed-line replacement (since area isn't served by fixed line phones). A care-taker would use it periodically to report well-being, and share some video / pictures of the place by sending MMS. The place has bad power-supply, and thus the objective of keeping phone always charged. I do not want to hand-over the phone to the care-taker, since he doesn't live on this property.