These things seem to be very sensitive to over charging. Probably best to use a power timer that only charges it occasionally. Mine swelled so much that the back popped completely off and wouldn’t stay closed except with rubber bands. Eventually, the battery became pretty much useless and it would constantly reboot whenever it was  unplugged.  I bought an old one from eBay to swap batteries. Of course, pulling the battery is a pain because it's glued down (work a credit card under so you don’t pierce it). Then there is hardly any wire length to work with and the connection doesn’t slide off parallel to the circuit board as it might appear. You need to lift or pry it up off of the circuit board. Since there is almost nothing to get hold of, it’s best to slide a paperclip under the wires of the plug and carefully pry them up (pressure perpendicular to the circuit board) by lifting there and it should pop off.  Also, the back just pops off, but remove the SIM card and all 5 screws before popping off the front.