Re: (ET) Dielectric grease

["David Roden" <etpost drmm net>]

On 12 Oct 2009 at 9:10, Chris Tromley wrote:

> I have no doubt the conductive greases are quality products, I'm just 
> not sure
> they improve conductivity that much.

I remember a discussion of this kind years ago on the EVDL.  Several 
people 
who had different brands of this stuff each took a blob and stuck ohmmeter 
probes in it.  IIRC, nobody measured any significant conductivity.  There 
might have been one or two brands containing copper that had a little.

A very thin film may have resistance low enough to measure, but the real 
utility of Noalox and its ilk is in preventing corrosion between 
dissimilar 
metals (specifically, copper and aluminum).  When you assemble those 
metals 
in a connection (as in using some brands of large lithium cells) this is 
important.  

With lead I'm not so sure.  I have to admit, though, that I've used 
vaseline 
on battery connections for many years.  It's mostly from habit, I guess. 
My 
father used to install auto batteries that way (and even flashlight 
cells), 
so I've done it that way for most of my life..  

It seems to be like that "Arctic Silver" heatsink grease.  Adding silver 
to 
it sounds like somethng that should make it conduct more heat.  But I read 
a 
pretty carefully implemented test of it some years back.  In practical 
use, 
properly (sparingly) applied, good old white silicone heatsink grease 
works 
just about as well, for a lot less money.

If you really want great conductivity and corrosion resistance, use lead 
or 
lead plated battery jumpers and weld / lead-solder them right to the 
battery 
terminals.  I haven't had personal experience with it, but I'm told that 
industrial batteries are sometimes done that way.  Probably 20 years ago, 
an 
EV conversion company (Soleq) built their cars that way, too.


David Roden - Akron, Ohio, USA

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