What do you use for cell welding?

WheezyRider

Esteemed Pedelecer
Apr 20, 2020
777
390
I bought a Sunko 737 welder, and I used it to build a few packs, but it is not at all safe and reliable.

It relies on a 20A fuse in the 13A plug (with a mains cable probably rated at 10A) and after every 30 or 40 welds, it will blow that 20A fuse. It can also only be used in houses that don't have power trip circuits, because it will cause them to trip after one or two welds.

It overheats after about 100 welds and sometimes it gets so hot, smoke comes out of the transformer in the welder, if the thermal trip fails to shut it down.

Recently I bought a MOSFET/microcontroller based welder for connecting to a car battery, but it failed doing the first weld.

What are other people here using?
 

wheeliepete

Esteemed Pedelecer
Feb 28, 2016
1,691
592
57
Devon/Dorset
i'm using a Sunko 709 which works OK and has prob. paid for itself after 4 years and a dozen or so battery packs. If I was to replace it, I would go for the Malectrics Arduino welder which is well supported.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
8,982
3,563
Basildon
I have a Sunko 788+, which I've used for loads of batteries. The electrode arrangement is a bit wafty. I had to put n insulator between them, and I file my own electrodes out of 3mm copper. The electrodes get hot after a few welds, which you'd expect when welding current goes through thin copper. I have to take a trest after about 10 welds.

Hint: For the best welds, specially in a second layer, cut a slot in the strip to stop the current taking the shortest and easiest path through the strip between the electrodes, or buy slotted strip..
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
13,356
5,181
57
West Sx RH
I use the Malelectrics one, even these mini/micro welders one has to be watchful of the heat build up. Though they do have an integrated fan.
The key with these is to buy a quality high 65C rate 4 -5ah lipo.
 

WheezyRider

Esteemed Pedelecer
Apr 20, 2020
777
390
Interesting stuff. Here are some links I found that people might find useful:



 

Advertisers