Dude, I didn’t know you bought a Gran Torino… sick!
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Edited.
I just wrote something really bad. Fuck you Ted for making me write that.
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on a 12x5 grid it would be easy af 
@hypocist I hate to say it, but the unwashed long haired man in the bathrobe and sunglasses is right. This layout is far superior to the one you showed above, unless you have some constraint in your build forcing you to use the layout you picked.
With the layout Ted suggested, you could use a single strip of 30mm (for 21700 cells) or 25mm (for 18650 cells) to act as both series and parallel connections. Then you would just need one bus bar connecting group 6 and group 7, and you’re off to the races.
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For an 18s5p p42a which is better for series connections to handle the current? 2-14awg wire or 2-12awg?
if you have space for 12 I see no reason not to use that, just to be on the safer side.
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I think the stress is getting to you man… put down the electrodes and take a ride. 
I showered… so there.
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The idea of having your P groups simply be 5 cells wide still holds as was mentioned.
That way you have most of your series connections as 5 nickel strips bridging over, and only need to add a bus for where group 6 connects to group 7, as was shown above.
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@BenjaminF @TheRef @TheBoardGarage I really appreciate your advises here
I done some changes according to your guidelines.
0.3x10=~21A x5=105A running cool
on bus bar I choose 0.3x10 = ~21A and presoldered 13mm braided copper =~101A= 122A running cool
is that good enough now? 
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Do you have a good welder? .3 isn’t easy to weld with.
I work in a place where there is an industrial welder for thin metal sheets. I have already done some tests and it works like a charm
I’m curious about your current expectations. Maybe I missed it, apologies if I did, but is this for a board? If so, then you likely don’t need to actually accomodate a running current of over 100 amps. Certainly not as a continuous pull.
Not that there is anything wrong, in theory, about your setup, but the practice of it depends on your physical skill of execution, and usually soldering copper braid across an entire length of cells without causing much or any heat damage, is a mildly delicate task.
If you have the expertise and soldering proficiency, then the point is moot, but I think it’s fair to look at what your likely current draw is in a more realistic application. I’ve never seen any eskate draw 100 amps continuous. I’ve rarely seen a board peak at 100 battery amps. I’ve seen it, but not in the majority of cases.
And since your pack is a 5p of P42A, I don’t think there will be the performance you expect if your draw is close to 100 amps for the majority of a ride.
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Dont try to solder that braid right onto the nickel on top of the cell. Make nickel tabs, solder to those.
This is why I dont use these spacer things, makes maneuvers like this really hard
Assuming I want to build a 12s10p with 21700 cells for a Ubox v2, should I go for:
- ~10A/5Ah cells
- ~30A/4Ah cells
I want the battery to deliver ~60A continuous and ~100A burst, 4wd should be a possibility later on.
this
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Yes, this goes to mountainboard 2x6374, ive got many hills at my work-home path and weight about 110kg (big boi here)
I know that this setup is never gonna be in situation where 100amps cont. is nessecary but if I can build that cause I have cheap acces to materials then why not, let keep cells cool 
This is exactly what I want to do. Im aware about heat comes from solderiron.
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Which 5Ah cell and which 4Ah cell? The capacity spec only tells you how well it might run when at under 1A. When using cells at above 1A or so there are other things you need to look at, like the actual Wh of energy it delivers at the power level you will run at.
A 4Ah cell can easily run for longer than 5Ah cell at certain power levels. Let me know which cells you are thinking about using and I can help you choose the one that will perform the best for your setup.
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For .3mm nickel you need around 100J for each weld, its a real bitch to work with, trust me I’ve tried. If you have a kweld you get maybe 6 welds done before it starts burning your fingers.
Nvm didn’t see that you already adressed this.
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I haven’t thought of specific cells, since it’s more a question of what can I buy at the moment in the EU.
Contenders are:
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