[Baffles]

The battery itself doesn't have a memory, however it is still affected by electronic memory, hence the need for recalibrating it. The controller in the battery which stores the full/empty charge levels and controls charging/discharging has to be trained to the actual levels of the battery, so when you run it until it shuts off, it relearns the empty value, and when you charge it full it relearns the full value, making your battery gauge accurate for a while.