Re: hp41c negative battery Message #2 Posted by Wayne Brown on 31 July 2003, 9:02 a.m., in response to message #1 by hugh steers
Yes, that's quite possible. When batteries get low on charge, minor differences in manufacturing cause some batteries to run completely out faster than others. If one goes completely dead then the others that still have a little charge will begin to "reverse-charge" the dead one. That's why you always should replace all the batteries at the same time with fresh ones. Mixing old and new batteries can produce a situation where a significant portion of the new batteries' power is going to reverse-charge the old ones, causing the overall voltage to drop (perhaps lower than the device's requirements) as well as shortening the life of the new batteries.
This is a major cause of death for NiCd battery packs. Letting the pack run all the way down can produce this reverse-charging situation in one or more cells, causing damage to those cells. Often a dead NiCd pack will have several perfectly good cells and one bad one.
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