I've soldered nicads with a 200w soldering gun before. that's going to
be your cheapest diy solution to battery pack creation. 

i used a small file to roughen the surface of the nicad, then a rosin
flux pen to add a *small* amount of flux to the battery and the
conductor. Then, soldering gun and plumbing solder (ie no flux in the
solder), got me some reasonable results.

The key is just getting a load of heat really quickly, you don't want to
cook the battery :) i hear they go bang if you do that :)

> -----Original Message-----
> From: piclist-bounces@mit.edu 
> [mailto:piclist-bounces@mit.edu] On Behalf Of Michael Rigby-Jones
> Sent: 13 April 2005 10:45
> To: Microcontroller discussion list - Public.
> Subject: [EE] Spot welder for battery terminals
> 
> I'm after a spot welder suitable for welding tabs onto 
> NiCd/NiMh cells for making custom battery packs in low 
> quantities (i.e. not enough to get the cell manufacturers to 
> do it).  Cost is a major factor and I'm happy to DIY 
> something if needs be.  I have found a hobby spot welder at 
> http://www.hobbyspotwelders.com/HS300A2.php which just uses a 
> bank of capacitors and a solid state relay, but the price 
> seems very steep for something that was clearly knocked up 
> from a Radio Shack hobby box.
> 
> Has anyone DIY'd a spot welder that gave good results?  What 
> are the pro's/cons of a capacitive discharge solution rather 
> than a high current transformer? 
> 
> Any information appreciated
> 
> Thanks 

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