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Discussion Starter #1
I recently took apart a drill power pack, 18vlts 1.8AH. Now to make it into a usable pack, 2 of the cells had to be moved to the ends, no problem. However, I now need to re solder the strips to Plus and negs.
So, basically what is a safe way to do this? Hot iron, resistance solderer or is there some other method/
Thanks in advance.

Rod
 

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Use the hottest iron with the largest tip you can find. Tin the strips. You want to expose the cells to heat for the shortest time possible. Heat kills cells. Hope this helps.
Dave
 

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Rod,

If you have a "battery store" go there & ask them to solder the battery's for you.. You will probably fine neat things you will want to buy also.. Like battery's with more Amps.. They can also shrink rap the pack for you..

BulletBob
 

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Use a fairly big iron. They're not hard to solder, that's what they're for.
 

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Rod, how did you get them apart in the first place? Just twist them back and forth till the solder broke or did you melt them apart? If you use the existing melt point to re-attach to the bigger part of the pack. Also key any unsoldered surface with a bit of fine sandpaper maybe and a smear of non-corrosive flux if you have any.

I've made up plenty of packs from scratch, not always with tagged cells....if you prepare the points first your iron will only need to be on there a split second...

Currently making up small 3.6v packs for LED coach lighting...



These are the new hybrid NiMhs that take much longer to run down on their own. Just the thing for lighting where it might be weeks between operations...
 

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Normally, they are spot-welded together with strips of ss. That keeps the heat down during assembly, and keeps from damaging the cells.

In my experience, I have never damaged any cell to any measurable amount by soldering to them, of course hot quick iron, lots of flux and do it quick.

Regards, Greg
 

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Discussion Starter #7
Thanks Chaps. When I had to take them apart, I had to cut one tag, no problem, easy to solder back together. The other tag came away from the bottom of the cell, it left no solder residue, I would even go as far as to say it was probably a dry joint(?), thats the cell that I have to do a reattachment to.
So, Large hot iron, non corrosive flux, abraided area, low temp solder, quick as possible.

Thanks all.
Rod

PS I like the idea of a battery shop and heat shrinking the pack, not one around here unfortunately.
 

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Used to solder directly to batteries all the time. Lately, they seem completely solder repellant.
 

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Rod, like I said, the "tags" are not soldered, they are spot welded. Groups of cells might be soldered, but usually the connection to the cell itself is spot welded. Look carefully, often you can see the 3 or 4 little "dots" where the current penetrated between the "tag" and the cell contact.

Regards, Greg
 

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I have found that it is much easier and faster to solder to a battery if you first scrape the surface to be soldered with a knife or file.

This gives a rough surface that is clean and solder sticks to it much better and faster.
 

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A small wire brush on a dremel works great and does not leave gouges and is more consistent. Then clean with a bit of solvent, and use flux, and you will get a picture-perfect solder joint.

Regards, Greg
 
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