Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!think.com!eplunix!raoul
From: raoul@eplunix.UUCP (Nico Garcia)
Newsgroups: sci.electronics
Subject: Re: mixing bettery types. Why not?
Message-ID: <1049@eplunix.UUCP>
Date: 26 Mar 91 22:19:47 GMT
References: <77759@bu.edu.bu.edu>
Distribution: usa
Organization: Eaton-Peabody Lab, Boston, MA
Lines: 20

In article <77759@bu.edu.bu.edu>, jdubb@bucsf.bu.edu (jay dubb) writes:
>    I was wondering. I often see warnings on electrical equipment to
> not mix battery types. Can anyone explain to me why this is so (or,
> maybe it is not so)? I have racked my brains trying to think of a

Number of reasons: two batteries in series, for instance, will have
the same current flow through them. Since different types have different
amounts they can discharge, one of them will run out first and may start
reversing cells. And recharge circuits for ni-cad may not be compatible
with gel-cells, for example. Also, different battery chemistries have
different voltages. Ni-cad typically has 1.2 volts per cell, and alkaline
has 1.5. This means that ni-cads in parallel with alkaline will either
be drain the alkaline and overcharge themselves, or diode protection
will cause the alkaline to drain, then the ni-cads.

All sorts of problems. Don't do it if you can reasonably avoid it.
-- 
			Nico Garcia
			Designs by Geniuses for use by Idiots
			eplunix!cirl!raoul@eddie.mit.edu