----------------------------------------------------------------------
Message: 1
Date: Sun, 26 Nov 2023 14:13:04 -0500
Subject: (ET) E20 cells replaced
Content-Type: text/plain; charset=UTF-8; format=flowed
Finally finished replacing the E20 rear string of 20 cells. After 20
years it is a job to do, here are some of the key issues:
1) Holes should be tapped.
I have no idea why but when I remove the stainless steel bolts after 20
years I find either brown "dirt" or black tarnish on the cells. No idea
why but in order to re-use the stainless steel bolts I need to clean
each one with my grinder/wire wheel in order to re-use them.
Also I've found it's a good idea to re-tap the holes which once again
results in a small amount of brown crud to come out in a powder format.
No clue what that is, but there it is.
2) The nickel plated interconnects hold up fairly well.
Now this is in an E20 that has been stored outside, driven rather hard,
and bounced around in the battery box for 2 decades, but oddly enough
the John Lussmeyer nickel plated cell interconnects are not too bad.
Some of them have some corrosion right at the slots for the bolts, some
of them were dirty on the bottom, but none of them showed signs of
serious damage or disintegration. This is pretty good since the
interconnects are copper on the inside with nickel plating on the
outside, but they seem to be holding up well.
Still a few have nicks, and copper sulfate is visible at those places.
So in other 20-40 years they may need replacing, we shall see. Note that
on cells I have had stored for 15 years I see no damage on the
interconnects.
3) Batteries need to be removed and the posts cleaned.
While the interconnects are good, the battery posts almost always have a
lot of tarnish that needs to be cleaned off with a wire wheel. Not sure
if this caused resistance in the overall pack of cells, but when
removing the connections you need to clean off the battery posts.
4) If a cell has 0 volts after a charge attempt it's shorted.
In a charge failure accident the cells will short due to heat melting
the polypropylene separators and warping the plates. Sad, but this seems
to be the way to kill these batteries.
More later.
C
------------------------------
Subject: Digest Footer
_______________________________________________
Elec-trak mailing list
------------------------------
End of Elec-trak Digest, Vol 21, Issue 79
*****************************************