alw@eddie.MIT.EDU (Alan Wu) (12/30/87)
Be absolutely sure that rechargeable batteries are NiCad before trying to discharge them completely. Nicads sometimes need this done several times to cure the "memory effect" of partial discharge, but running the pack down too far can be *fatal* to the sealed lead-acid batteries that are also being used more frequently these days. If the specs don't say, you can distinguish these 2 types by measuring the individual cell voltage or dividing the nominal battery voltage by the number of cells. Nicad is about 1.25V, while lead-acid is about 2V per cell. Also, over-discharging Nicads can cause them to develop cell reversal and/or internal shorts. As a rule of thumb, the best thing to do is to operate the device until it stops running, then immediately recharge the battery.