There are several different battery types, NiMH, NiCAD, and Li-Ion, and Poly-Ion. The newer phones have Li-Ion (well most of the do) or Poly-Ion. These do not have a "memory" and can be charged whenever it is necessary. So you don't need to drain the battery of the 8260 (which I have)before charging. In order to get full charge out of it, you'll need to charge about 2-3 hours more after it says battery full (trickle charge).