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as I wrote abobve I’ve shorted a battery while building it and there wasn’t anything to notice other than the sound of a pressure valve blowing and hissed in a cell. a short can happen without you even knowing possibly…and then later could put it on a charger.
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I’m wary of saying stuff like “don’t do this, do it this way”. A lot of it is in the execution and knowledge built up by making mistakes (experience). For those who are still developing the knowledge/experience, thoughtfulness and being aware of what the dangers are (failure modes) is going to really help. IMO shutting down the discussion doesn’t help this.
And we’re all here because we like to do things our way, right? Tweak this, tweak that, I think this could be better, etc. And we’ve all blown various things up.
I know I’m still relatively noob, and a ton of this stuff has been discussed endlessly in the past on endless-sphere.com, etc., so I understand some of the impatience of the old timers. And I question if I’m being naive…
I don’t see anything inherently wrong/bad with OP’s design. Bunch of people looked it over and agree, although they feel nervous about the unfamiliarity.
Execution, this is where we’re all learning from OP’s experience, I think. @Quezacotl I hope you keep at it and figure out what went wrong, and how to improve safety, or how to check things between steps to affirm things are going well.
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10s3p dual stack dual row configuration example Cells are not connected,not insulated, only layout example
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Nice touch with the insulation between the packs too!
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Lol I can’t resist even when absolutely nothing is connected 
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Send me the cells and I’ll make it. There is NOTHING wrong with the design
Lol I never said it can’t be made, I can make it too, but why, when a more reliable method exists?
Why is your method more reliable?
Dual series links, more even current distribution, single fold
His pack has 3 series links.
His pack current distribution is good with the exception of connections 3/5 which are on the outside where the current goes through one tab. Still not that bad…
Your single fold is on the edge of the battery, with enough vibrations those tabs can break easy.
Vs
His fold is supported throughout by the several nickel tabs creating less strain overall.
His design does not require insulation between folds. Vs Yours does
You can find pros and cons on both designs. One is not necessarily better than the other. Just because it seems complicated, it doesn’t make it bad.
I wouldn’t do it either way, but I am not claiming that the way I would do it is the end all be all of battery design.
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I’m no battery god lol uhm there are plenty of series connections that are single in there…only 4 are triple linked, so current draw can be quite diff between the series from one end of the pack to the other
@PXSS come on, have you ever built a pack with a hanging cell that you have to connect to it’s p group after it’s assembled?
I’ve said all I have to say on this topic, I’ll just patiently wait for the next it’s on fire thread
Yes! Plenty of times actually! I’ve also built packs with parallel groups have cells across different levels (each fold would be a new level) where I have to run a wire across two cells to connect some of the cells to the rest of the group!
You forget that I do this as a living (and somewhat hate it, which is why I dont offer to build packs for others), I have designed battery packs that are crazy but are the (what I consider) optimal configuration for the specific task.
There is a battery pack I make that has 40 folds in a 2 level pack. I hate building it because it takes so much time but it has to be that way in order to fit the space available.
Looking at pictures on the first post and the one with the connections numbered on post 68:
1 - negative - 3 tabs triangle 2 - 3 series tabs (2 to the bottom cells and 1 to the top cell) 3 - 1 series tab on outside 4 - 3 series tabs 5 - 1 series tab on outside 6 - 3 series tabs 7 - 3 series tabs 8 - 3 series tabs 9 - 1 series tab on outside 10 - 3 series tabs 11 - positive with one tab
Again, there are spots where he does have one series tab on the outside of the pack, but they are not detrimental, especially if he doubles or triples the tabs on top of each other.
All good, do you think this is the optimal layout for the OP, considering his experience level?
No, but again, I don’t think yours is either…
In all honesty, I would do his before yours. Mainly because I would not trust the 2 tabs to survive after many vibration cycles… 
WHAT I WOULD DO is the same triangle pattern that you have but instead of going all the way to one side on one layer and then back on the other, I would go back and forth between the layers so that the fold is supported throughout.
I use 1/2" copper braid for the fold, 2,3,4 pieces depending on P count
Dont want detach from the OP’s story but how bout some criticism over here. Ive got a pile of battery handlers here and want to see what you think. You think this is safer or more dangerous? the tape surely cant keep compression as long as extreme (4) rubber bands I have coming but it looks nice with the clear stretchable tape. it’s .5mm copper strip 17mm wide. not going to cut into the insulation of a cell with no sharp edges. With a shorter strip of copper can stack them on top of each other too and keep the exposed copper recessed. too me its awesome and cant wait to put it on a new board with new motors.
how much copper strip you think I should put in, I read the thinner the better stacked and it contours to the cell but I’d like to see the math for current and conductivity of copper at this volume and forget it.
looking at it again here with more critical eyes the bands need to be able to get to the part they’re pulling better. that lip on the bottom really reduces what the band can do.
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Rubber bands perish with heat after a while. Maybe nitrile rubber might be better?
my best lead but surely there’s a band out there that can do it. even if I have to change them once a year i’ll be happy.
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Wtf. No no no no no. That’s terrible advice. What you’re saying is, “you made a mistake therefore you should never try again”. That’s so incredibly dumb I can’t even express it. How would anyone do anything if they’re not allowed to learn from their mistakes? Are you telling me if you accidentally missed a traffic light a nearly hit another car, you’d stop driving? No, you’d learn from your mistake and be more careful in future. Geez…
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