Battery re-celling or repairing

[dickm]

Is there an easy and reliable way of connecting/reconnecting cells within power tool battery packs? My elderly SIP battery nailgun suddenly stopped working and after stupidly dismantling the whole thing and taking hours to get it back together :twisted: , discovered it was an intermittent open circuit in the battery pack. Managed to sweat the connection back with ordinary solder, but suspect this does no good to the cell itself because the iron has to be held in place for 10 sec or so.
Have been wondering about trying to cannibalise some packs with tired cells to see if they will make one decent-ish pack, but this business of soldering connections to the body of the cell seems like a problem.
Any experience out there?

 

[Homerjh]

You need a big soldering iron, so it doesnt loose heat quickly, a general purpose one won't be big enough.

I think it is similar to http://www.axminster.co.uk/weller-sp80n ... th-led-80w but may be an expense for a one off job. But it has good heat and big tip so plenty of heat for quick melts, especially for battery terminals and suchlike.

 

[Myfordman]

Soldering is very bad for the cells. You need new tagged cells which are spot welded on with very little heat input.
Don't mix old and new cells either.
MM

 

[HOJ]

I use this company to re cell my batteries http://www.multicell.co.uk/index.html

Fortunately for me they have a branch in Norwich, they allegedly offer a Nationwide service

They will upgrade the AH rating as well.

I wouldn't bother with trying to resurrect old cells, once they stop holding a charge you will not get them back to 100%, as has been said, mixing good and bad cells will not work.

 

[Homerjh]

have you googled for a new battery, as said, bodging old batteries together will cause other issues and may not be reliable, so buying new may work.

http://www.sipuk.co.uk/nailers-spareparts.html

what batteries are in it? if old then highly likely nicad, so you cant replace with NIMH cells as they charge differently, and lipo wont be an option, but most places only sell nimh or lipo now.

if you can post the nailer model and details then maybe someone can help better?

 

[dickm]

Thanks for the replies, folks. The nailer battery now seems to be fine, though having a spare for the price given in the SIP website listed by homerjh would be great if only they were actually available! The tool has been long discontinued, and of course used a unique battery format, so once it dies it will probably go to the big nailer graveyard in the sky; certainly not worth doing a proper re-celling job on it.
I didn't think it was a good idea usually to try and solder direct to cells, but for the nailer, it did provide an instant solution for at least the short term. Maybe give up on the idea of cannibalising good cells from several dying Bosch batteries to make one decent one for the drill, though.