Aaron Konstam wrote: > > The issue I think is this. Some types of batteries have memory in the > sense if you change them when they are half charged they will henceforth > only discharge halfway. Batteries generally put in laptops and cell > phones (LI-Ion) this fault as far as I know and therefore they can be > discharged and charged at will. Also it is my belief that the circuitry > in these devices will not allow over charging. > Most laptop batteries have a small circuit built into them that keeps tract of battery usage. This is what reports the charge state of the battery. It recalibrates when you do a full charge/discharge cycle. (Full discharge being when the battery voltage starts to drop.) This is necessary because the voltage output on LI-Ion batteries remains constant for most of the discharge cycle. This circuit usually also controls the charging of the battery. One interesting aspect of this is that if you repair a battery by replacing cells, you have to reset the circuit to restore full charge/discharge performance. (There is Linux software to do this...) Depending on the circuit, you can also run into problems if you let the battery go completely dead - you may not be able to charge the battery without opening it up, and putting in a small charge to power the circuit. I am not sure why some appear to be designed to only be powered from the battery, and block incoming power from the charging source when the battery is dead... Mikkel -- Do not meddle in the affairs of dragons, for thou art crunchy and taste good with Ketchup!
