From a practical standpoint? If its too short to reach your ESC then it’s too short. From an electrical theory standpoint? No.
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Thanks guys <3 I feel so much better!
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It’s not about the length of your battery leads, Evan, it’s about how you use them.
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The stormcores recessed port makes life miserable man
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According to the 737G’s manual, as well as Sunkko’s website, the maximum thickness of pure nickel that the 737G can handle is 0.15mm, and only 0.1mm with the extended handpiece.
AC-powered welders like that have trouble drawing enough instantaneous power from the wall to get a good weld, without blowing a breaker.
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They don’t charge up a bank of caps and dump those into the weld?
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Nope, they’re simple transformers, with a serious step-down ratio, and very, VERY thick output windings. The 737G puts out something like 5v AC at 800A. They have a solid-state relay that limits the welding pulse to just few AC cycles, but during that time the 737G pulls something like 2.9KW from the wall. No wonder they blow breakers.
The power draw from the wall limits the instantaneous peak power, which is what’s needed for welding thicker nickel strips. The pulse from a KWeld or similar is probably 10-15 KW, not ~3 like these.
There are capacitive discharge spot welders commercially available, but they’re generally a lot more expensive than the “Giant hunk of iron and copper” models that Sunkko makes.
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There are kits to make the conversion you mention. @kevingraehl made a custom version of this a while back.
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looking for ways to modify the sunkkos to work off a cap bank, I found this video. looks simple enough and like it might be a great way to make the kinda doodoo welder I bought as a boobienoobie powerful enough to make batteries. check it out @tech.shit
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What video?
Is there any way I can make it work for 0.2mm? Like maximum power 2 sets of 2 pulses? Or 3 sets of 2 pulses?
Yeah he qelds .2 with ease and consistency. Simply wraps some awg4 copper around the transformer inside the unit. Duhhhhh, i forgot the link the vid. Gotta get back to my pc, im at work now byt ut was pretty much the first video when searching for sunkko mods…
Edit, there actually a fkn ton of videos for all kinda upgradage. Long story short, simply rewrapping the Tformer with heavier guage wire should do the trick. Might teport back next week qith my results if i dont wind up using my boss level welder to make my first batt.
Wish me luck, battery gods. Big shout iut and a very thank you all, this thread has been a life saver as much as its been a pima every time i learned anything that made me realize id just wasted a bunch of time and effort. Will either post pics or perhaps start a thread to document my progress and what. Should be a far cry from my first slapstick hobo salvage right here
I can’t help you there unfortunately, I don’t own a Sunkko to experiment with.
Comments, suggestions, and beratement welcome. This is my progress on my first pack and it isn’t coming how I’d envisioned. The groups wanted to shift around while I was taping them together and it bent the nickel some. I guess I didn’t align then well enough while welding. I should have 3d printed a jig or something. I almost just went to start over from scratch, but I think I’ll just try to finish it the best I can and do better next time.
Should I take the lack of comments as “That’s so bad I don’t even want to speak of it” or “Meh, there isn’t really much to be said about that”?
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It’s a bit soon to think no one is commenting.
You posted around midnight EST here in the US and some folks don’t check posts every day. Wait another day or so. Especially since no one has posted here after you.
Your post does wrap things up pretty well too…you know the pack isn’t great, you’re going to use it anyway, and you’ll do better next time. Not much commenting can be done after that. 
Asking for general feedback is also asking for everyone to take a bunch of time…which no one seems to have these days. It can help to ask a single specific question, perhaps about how to best stabilize cells before welding? Or something related to that to help keep things from shifting around as the pack is assembled. I think more people would respond since the answer can be short.
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Glue the cells together before welding, in a jig for example. Use hot snot or neutral cure silicone. If you don’t want glue, use cell separators (cheap on ebay or print them yourself). Then wrap the p-groups. If the pack goes into a high vibratory environment, f.e. a longboard, make sure to avoid balance wires crossing, and where unavoidable, put fishpaper in between. Also weld on little piece of nickel as tabs for the balance wires, that way they don’t have to go around corners.
Also make a perfect nickel piece to use as a template for more even nickel plates without crinkles.
And yeah, your pack looks like shit, but should be functionality-wise totally fine. 
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I did glue the P-groups together and then wrap them. The problem was more the separate P-groups sliding around once I had welded the series connections and went to tape the entire sides together. They all wanted to slide against each other in opposite directions. Also, I did plan poorly on the balance wires, but I have tabs cut, bent, and tinned to weld on top of the nickel that is there. I just haven’t done that quite yet. My welder seems to be mostly okay-ish, but the leads and electrodes are cheap and small so I have to take a lot of breaks.
As far as specific questions like mooch mentioned, I guess I’m just wondering how unsafe is this going to be if I do a reasonable job finishing it? Also is there anything short of starting over from scratch that I can do to improve it at this point?
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