New battery build 12s3p with samsung 40t's

Hello everyone
I need to build a new battery pack becuase my old 12s5p with 30q’s short cuircuted due to water damage (i’m not actually that mad about it because to be honest it wasn’t such a well built pack anyways and it gives me the opportunity to build a much better enclosure), i chose the 40t’s over the 30’s because of the higher discharge and capacity, but also because for the same overall capacity of the pack it is a little bit cheaper. The cells in the old pack were arranged so that they were perpendicular to the length of the board with 2 rows. Since I’ll be using the longer 21700 cells, i don’t think this arrangement would work as the pack would be too wide to fit on the deck. I’m thinking to put the cells flat and parallel to the board, but not sure how to solder together the p groups this way. I was thinking to put it double fish paper layers on bend the nickel strips over the top of the p groups and solder it that way. What do you guys think about this?

Like this:
bilde

Instead of this:
bilde

I was also using a smart bms in the old pack, but 2 of those have failded on me already and they take up a lot of space in the enclosure, so was thinking of using a more conventional BMS this time. I know that the bestech BMS’s are good, but any other suggestions?

How much space do you have? Use millimeters

About 150x300mm

150mm is technically enough to have the cells perpendicular to the deck, it will save you length of you do it that way

Only the cells would make it 140mm, plus the wires, nickel strips, inulation and foam padding, it would be increadibly tight, and my deck is 42 inches, so length isn’t that big of an issue.

Depends how you do the pack, look at this for refrence

From left to right it’s…only 5mm (pack runs 135mm at the widest)
Shrink wrap
Fish paper
Nickel
Insulation ring
Cell
Nickel
Fish paper
Fish paper
Nickel
Insulation ring
Cell
Nickel
Fish paper
Shrink wrap

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What do you mean only 5mm, which dimension is this?

Sorry that wasn’t worded clearly, the added layers for finishing the battery only added 5mm compared to the end to end length of 2 cells. That means using 21700 cells in that method makes a battery that is 145mm wide

Hmmm, ok. That looks very clean, if I can manage make like that I think it would be perfect. Is that a 12s3p? How long is it?

387mm long, 23mm thick

Ok, that’s quite compact I would say. Alright, I’ll go for the perpendicular layout.

Daly bms is also known to be reliable