Sorry; I misread that as "change" the battery, not "charge" it. Sure you can use it while charging it, but whatever you're running doesn't care if the current comes from the charger or the battery, . . . well, . . . most things don't care.
Think of a slow, controlled leak in a bucket of water as the current going to run something. The battery is the bucket. The higher the level of water, the higher the voltage. The charger puts water back in the bucket but because it runs on alternating current from the house, it's putting water back into the bucket with pulsating cupfuls, not a steady stream. That results in rapid voltage fluctuations at 120 pulses per second. Computers hate that and may do strange things.
Don't know if that helps or answers the question. If not, you'll have to be more specific with what's happening or what you're trying to do.
Oct 9, 2012 at 7:08 PM