Sonicare toothbrush had little charge and it bled down without using.

Replacing the battery from Amazon - 

Disassembly was difficult. To remove the base plate next time, I would squeeze the white handle in a vise slightly with the switch toward the jaws of the vice. Maybe 1/16 inch and then using small screwdriver pry base plate from handle. Start prying with a small screwdriver then use medium screwdriver to work the base plate slightly off. (The charging wires need to remain attached to the base plate.) Then push the end that attaches to the brush until the inner board slips out the back. 

My Sonicare had no screw holding the base plate secure but some Sonicare's have a screw securing the center of the base plate. I was then able to remove the rubber support pieces and unsolder the battery. I was able to get all back together and the sonic is working. The base plate no longer locks in place so some electrical tape secures the base plate quite securely. I will use it until the battery gets low and recharge to see if the recharge portion is still working.