Article: 10011 of rec.models.rc
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 uwm.edu!cs.utexas.edu!sun-barr!olivea!uunet!infonode!ingr!b11!naomi!lester
From: lester@naomi.NoSubdomain.NoDomain (Les Bartel)
Newsgroups: rec.models.rc,sci.electronics
Subject: Re: How to dispose of NiCads?
Message-ID: <1992Jul29.124224.26312@b11.b11.ingr.com>
Date: 29 Jul 92 12:42:24 GMT
References: <1992Jul27.161240.4905@nynexst.com> <k6lmatq.brunette@netcom.com>
 <1992Jul28.140405.28429@gdunix.gd.chalmers.se> <p5mmrwq.brunette@netcom.com>
 <1992Jul29.084514@ufps9.unifr.ch>
Sender: usenet@b11.b11.ingr.com (Usenet Network)
Reply-To: lester@naomi.b23b.ingr.com
Organization: Dazix, An Intergraph Company
Lines: 56

In article <1992Jul29.084514@ufps9.unifr.ch>, waeber@ufps9.unifr.ch (Bernard Waeber SIUF) writes:
|> In article <p5mmrwq.brunette@netcom.com>, brunette@netcom.com (Hal Brunette) writes:

[Text of 'zapper' deleted]

|> Please correct me if i get this wrong, i guess the above circuit requires
|> to remove the dead cell from the multi-cell pack, right ?

Maybe not, see below.

|> 
|> Which means, one has to take the Ni-Cd pack appart, and get the dead cell out.
|> The cells are usually connected with a point welded metal plate, which requires
|> you to rip the metal plate off the cell. 
|> Now, once you fixed your shorted cell ( you hope ),with the above circuit ,you will have to
|> solder the cell back in place, which isn't that abvious, if you apply to much
|> heat when soldering you may damage the cell, if you don't apply enough heat you get
|> a cold solder spot, in which case it may brake loose, due to vibrations.
|> 
|> The point is : You better know what you're doing, when trying to recover a 
|> 	       dead Ni-Cd cell.

Absolutely.

|> 
|> 	       Guess your plane or heli is worth more, opposed to the 20 bucks
|> 	       for a new Ni-Cd pack.
|> 
|> So, if you aren't too confident of fixing your Ni-Cd pack, return them to the place
|> where you bourght them.
|> 
|> -- 
|> ben

You don't have to remove the cell from the pack (unless it is in parallel
with another cell).  Just clip the zapper leads to the terminals of the
cell.  In fact, it seems to me that it may even work without isolating
the cell if there is a cell in parallel.  The shorted cell should take
most of the current, and the non-shorted cell some current as well.

	 Bad cell
	     |
	     v
   ___      ___      ___
--|___|----|___|----|___|--
         |       |
         |       |
         |       |
         |       |
	zapper leads

 - Les

-- 
Les Bartel			lester@naomi.b23b.ingr.com
Dazix, An Intergraph Company	uunet!ingr!b23b!naomi!lester