rmrin@inuxh.UUCP (D Rickert) (01/12/88)
Many thanks to the folks who have posted information about NiCad batteries in the last several weeks. Some of the postings were seriously in error but others contained worthwhile information. Specifically, the question of whether NiCads benefit from complete discharge was of interest. As an electrical engineer working in the quality area, I once had occasion to read the original report which claimed NiCad life was improved by short circuiting. The study was done somewhere in Europe, I forget where, and the discovery about shorting the cells came about accidentally when someone forgot to throw a switch. Now for the part where I learned a little. The original study was done with individual cells in parallel so the cells could not be reverse charged by other cells in series. I have tried to help cells along by leaving them to totally discharge but unfortunately I did this in an appliance that had several AA cells in series. The net result was some of the cells did short and I could not figure out why. It appears that cells will benefit from complete discharge but only if that is done with each cell individually connected to a load (as in the original European study). Leaving the cells to discharge in a typical appliance will more likely cause harm than good. Dick Rickert AT&T Consumer Products Laboratory