On 4/24/2013 8:18 AM, Ben Apollonio wrote:
Not only does the aluminum want to oxidize, but you're mating it to copper
straps. If any moisture gets in there, you've just made a galvanic cell that
wants to corrode itself further. When I looked into this for my 914, I settled
on a (slightly hard to find) grease called Penetrox A. There were some
aspersions cast on Noalox, but I'm afraid I can't remember the details of what
they were -- perhaps its applicability to aluminum-copper junctions vs. just
aluminum. In any case, I've had to remove my batteries once or twice, and the
Penetrox A has protected the terminals nicely. Shiny as the day I first
installed them.
A lot of work has been done to figure out how to make reliable
connections to aluminum conductors. Unfortunately, much of this
knowledge and experience is not being applied when connecting to lithium
batteries.
For one, you don't want to directly bolt copper and aluminum together.
"dry". It almost certainly leads to corrosion.
You need to use some kind of "grease" or other sealant, to keep air and
water out of the interface.
For another thing, you must have very high contact pressure, to crush
the aluminum surface and break up that tenacious oxide film.
I suspect the best way to do it is to use *aluminum* jumpers, and *weld*
them to the cell terminals.
Failing that, electroplate some other metal onto the aluminum terminals,
so the connecting surfaces don't have that troublesome aluminum.
--
You never change things by fighting the existing reality. To change
something, build a new model that makes the existing model obsolete. --
Buckminster Fuller
--
Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm
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