[NTLK] Removing plastic sleeve of cells in battery pack rebuild

From: Frank Gruendel (newtontalk_at_pda-soft.de)
Date: Sat May 14 2005 - 17:17:16 PDT


> I don't know if the plastic sleeve is needed
> on the batteries (any experts out there agree
> or disagree?) but you can gain some much needed
> clearance by removing the plastic sleeves from
> the cells. I don't know, though, if the plastic
> is needed to protect against cell rupture or
> electrolyte seepage.

The sleeve is primarily needed for isolation. Be aware
that 99.9% of what is below that sleeve is electrically
connected to the negative contact of the cell. Without
the sleeve it can easily happen that the negative
contacts of two opposite cells touch, which must be
avoided. If they do, you'll get an excellent demonstration
of how fast fully charged NiMH cells can become so hot
that they will melt the case.
It might be an option to remove the sleeve at the top
and at the bottom and leave it in place where the cells
are closest together. However, using a Dremel tool to
gain additional space is much safer electrically. With
today's cells being in the 2300 mAh range, you'll have to
do this anyway since these cells are slightly thicker than
those Apple used originally. Even if you clean out the
remainders of the old cells completely, this normally isn't
enough.

Frank

-- Newton software and hardware at http://www.pda-soft.de

-- 
This is the NewtonTalk list - http://www.newtontalk.net/ for all inquiries
Official Newton FAQ: http://www.chuma.org/newton/faq/
WikiWikiNewt for all kinds of articles: http://tools.unna.org/wikiwikinewt/


This archive was generated by hypermail 2.1.5 : Sat May 14 2005 - 18:00:00 PDT