This one one of them. I think there was a second. I didn’t cap that one tho.
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Right off the bat I see…
- skinny ass nickel
- square corners
- a pattern that can’t carry current
- nothing holding it stable except glue and tape (okay for small but this is huge)
- hella inconsistent welds
Such a shame
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There’s even more than that. I don’t like to try and push people out of the community or some shit. But those packs are not safe. And I don’t wanna see anyone buying them get hurt or start a fire or anything. It’s makes the whole community look bad.
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Yeah, looks like 0.1x8 maybe? or 0.15x8
Definitely square and hanging over
I don’t think this pack is done? I don’t see all the series connections? I’m not trying to side with the builder in question but I am just trying to logic through it and learn from it.
I agree here too they don’t look good at all. I think that this pack could have a chance of delivering the current but I think it would make the nickel quite hot. What cells are these? 50e?
I’d be most worried about the folded nickel in the middle breaking from vibrations
Edit: maybe the other series connections are nickel on the bottom, in that case I can’t imagine how hot it would get if you pulled real current through it
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Iirc those cells are 40T which makes the improper use and sized nickel even more egregious.
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Oh lord yeah in that case way worse. I’m not familiar with the 40T / 50e color difference so I didn’t spot it
All in all it looks like a noob pack
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What other errors do you see? Might as well learn from his mistakes right
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Ok here is a couple
1)Balance tab coming of the (+) side of the can.
reasoning: if the wire wears through the corner of the cell its sparky time. Placing the balance wire only along the negative side of the group it touches makes this kind of short much less likely because loss of insulation does not result in a short.
- use fish paper under positive leads off the p group. reasoning, see above. the can itself is negative, that sharp corner is begging to touch the can and let some smoke out.
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Couple more things:
BMS tabs on positive side, since this can create a running short on the edge/can I only put tabs on the negative side of the cell.
Weld spacing. You don’t want to have such a large distance between your electrodes when welding. As you space them out power is lost in the weld as heat to the nickel and cell. Sure it’s still a lot less than soldering. But the greater inefficiency and inconsistency add up over the hundreds of welds that go into a big pack. You can test this by welding close and far apart, theres a noticeable difference imo.
Also, No fishpaper. I know people use exclusively glue but I’ll never think it’s a good idea to not use it between groups.
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Good to know those are things I’ve started accounting for already 
I was wondering about this too, I thought they seemed a bit far apart. I will be wrapping each of my P groups in heat shrink when I finish my battery
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Sloppy start, sloppy finish.
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accurate
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Sloppy seconds?
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ahh man, yeah this is scary for 40T especially–wonder how much he charges for this pack too.
I’ll happily do better for a 10% discount 
He charges about double the cell cost at least, he also gives a 40% discount on his enclosures with it but those are about $5 in materials so…
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since the only thing I ever ordered from tiller was an enclosure that took 6 mo, and only arrived after @skunk went to socal and personally advocated for me, I don’t intend to ever order an enclosure (or a battery for that matter) from Dave again.
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damn. you really covered the entire surface area possible with nickel 
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And then layered it. Many angry pixies will be travelling through this one.
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