On Sun, 09 Mar 2008 11:10:20 +0000, "Ron(UK)" wrote:


:
:Interesting stuff, and there is a correlation between disimilar metals
:corroding - sacrificial anodes and all that, but I`m not sure that is
:what happens in the case of nicad battery packs
:
:It`s not only in metal cased fixtures tho, most of the garden lights
:here are plastic - they only cost a few pounds, not worth repairing really.
:
:I spent a great part of my youth and early adulthood messing about with
:radio controlled models, and whenever a Nicad batterpack failure
ccured, it was always the negative wire which had turned black and
:literally rotted away. I don't think moisture has much of a role in the
:matter, as many battery packs are quite well sealed.
:
:I wonder if the same problem occurs with types of battery technology
ther than Nicad, NiMH for example?
:
:Even in cars, I believe that it`s usually the Negative battery
:connection which gives trouble, either at the battery termnal or the
:chassis ground connection.
:
:
:Ron(UK)

I am sure there is a scientific reason for corrosion being mainly on the
negative terminal but I can't quite rationalise it at the moment. I have seen
many reports on car battery negative terminals and wiring corroding and I have
also seen a lesser number of complaints about the positive terminal.

Without going into a scientific discussion on the subject perhaps T.R.B Watson
has a plausible simplified explanation.
http://www.westcoastcorrosion.com/Pa...%20Corrode.pdf