Need advice on Spot Welder for batteries

[Sigma957]

Hey Guy and Gals,

I have a question about spot welders for batteries.

I am looking for a good and safe cheap spot welder for batteries.
I want to spot weld some strips to AA and 18650 batteries to make some battery packs.

I went to Instructables and there are so many there I have no idea which would be good to try to make.
Or if there are ones that are already built buy companies.

I am not a business and just need to repair/make new packs for several products I own.
Each pack I need to make are 6-8 AA batteries and 18650 Batteries.

So can anyone please give me some advice and/or point me in the right direction?


Thanks in advance
Sigma

[thm_w]

https://www.eevblog.com/forum/reviews/battery-spot-welders/
https://www.eevblog.com/forum/reviews/suggestions-wanted-for-a-spot-welder-for-battery-tabbing/
https://www.eevblog.com/forum/reviews/mini-spot-welder-from-aliexpress/
https://www.eevblog.com/forum/reviews/battery-spot-welder-suggestions/

[Stray Electron]

  I've spot welded batteries. I found a spot welder in a surplus store but the hardest part for me was getting the nickel metal strip for connecting the batteries. I was carefully pulling the strips off of old battery packs and was reusing those but I never had enough of them. I was buying batteries (individual cells) from a nearby industrial company but eventually I just started having them make the entire battery set and then I would then install that in the customer's old plastic housing.  This was about 25 years ago but I think they only charged me about $0.25 per connecting strip and they gave a good discount on the price of the cells and the discount usually covered the costs of having them install new connecting strips and spot weld them. 

  I never really investigated the internals of the spot welder but I think that it was nothing more than a variable AC transformer where the output was rectified and that charged a bank of capacitors and when you stepped on the control lever it closed the contacts in a large mercury wetted contact relay and dumped the capacitor charge to the two spot welding electrodes.

[Sigma957]

Hello,

Thanks for the fast reply and sorry for my late reply.

I will take a look at the links and see which is best for my needs.

Thanks
Sigma

[fortunamatada]

I think you will find safe and cheap only appear with an or between them regarding battery spot welders.  You will either go cheap and put your faith in a Li pouch battery made to less than stellar standards to output over 1000A to be able to weld the nickel strip onto another Li battery or pay in for a cheap spot welder and full blown car battery, which while safer, won't survive that process very long leading to needing to buy another one, or paying upfront to get something that will help you skip past duel wielding sketchy li batteries at insane current draws over and over and hoping this time wont be the time it goes roman candle but far less fun.