Sunkko works okay but I did have issues with it when I had it on for a long period of time it just stopped working all together I tried a few hours later and it was good to go again. I use the Boss spot welder now it works as long as your lipo has power lol
I have brought this one - https://www.keenlab.de/index.php/product/kweld-complete-kit/ Have not yet used it properly, so i cant say if its good for long time use
You can see more about it here on youtube - https://www.youtube.com/results?search_query=kweld
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I’ve been practicing at Psychotiller’s shop with a Sunkko 709 seems to work good and he’s probably built a lot of packs with it.
I wonder if the malfunction is using it continuously for too long. With my Malectrics spot welder I don’t use gloves while spot welding and as soon as the prongs on the end get hot to the touch (after about 15-20 welds at 30ms pulse) I stop using it and let it cool off while working on another part of the board. I have soldered over 150 cells with it now and no issues.
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I have a sunkko 709a I would be willing to sell if interested. I bought it used on here but never built a pack out of it. I did make maybe fifty practice welds so it seems to work fine.
I have a hakko Fx-100 soldering station and ended up doing fused cells. That station made quick work of the pack.
I think I’ll probably do cell fusing for a battery pack if planning on making for an ebike. Any advise you can give on how you did it? Could you post any pictures? I am gonna do a 6p20s pack with a max current draw of 90A and I’m not exactly sure what gauge and length of fuse wire I should use.
What cells? What’s the expected amp draw?
30Q cells w/ 15A continuous
22 awg single strand copper is good. It fuses around 40 amps which a short circuited cell will definetly see. I went with 20 awg for reduced resistance as it will fuse at 58 amps. I think a shorted quality cell can deliver as much as 300 amps so I feel protected. 24 awg melts at only 29 amps which feels far too close to what we can see. I don’t want one to ever fail under normal high demand situations.
Aluminum would be better since it has a lower melting temp but it’s even harder to find 
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Nice, I like this. This is how Tesla all builds their packs. Do you know how the pack behaves with one shorted cell?
Unfortunately no. I wish I had a solution to view all voltages or get an alert.
Thanks for the info & pictures! I will definitely be trying this myself. Also, I wonder if making an enclosure out of clear polycarbonate would work to see each fuse without removing the enclosure. Maybe @psychotiller would be able to make an enclosure out of some clear polymer?
I have no idea if polycarbonate works well for vacuum forming.
They make displays that show the voltage of each p group. That would be best probably. But I’m not sure how reliable they are or if they drain the battery.
Yeah that would work, but it would be pretty sweet to have an enclosure where you could see the internals. Would look super awesome with good wire management. I put so much work into making the internals look pretty so it would be nice to show it off!