If you put cells in series you need to connect + from one to - to other cell. In your diagram it looks like you connect +with + which would be a parallel connection.
If you make 3x 12s rows you cannot connect the bms so that it balance all cells. You need to make 12x 3p packs to get the balance leads connected right
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Thanks Andy yes you are correct I have just seen that now I was going to do one up and one down plus and minus. But due to space I can only fit 9 cells in a line hence the drawing I will re do this
So you will not use a bms? How you plan to connect the cells? If you use nickel make sure you use multiple layers in your setup. If you go the 3row 12s way the current inbetween the parallel connection is higher. So a single layer 10mm .15 nickle wouldn’t be enough.
I do want to use a bms I just haven’t attached the balance leads in the diagram. So what would your recommendation be for the copper nickel strips please?
I have been trying to rack my brains in understanding how this works take a look at this diagram I just couldn’t see yet how the bottom will look after
Sorry for the late reply. You need to reply to my question directly or add me, if no I don’t get notifications. First thing I would change Go like this: pack1- to pack2+, pack2- to pack3+ and so on. You now go like pack1- to pack2+, pack2+ to pack3-. Hope you understand. Would draw it but don’t have anything to hand. Second, you don’t need connections between level1 and 2. just draw your pack in one level laid out. Guess it’s more easy. Than fold it down after pack3 but don’t connect the levels. Make sure they good isolated from each other to don’t short.
With your latest layout it’s more easy. Inside one parallel pack you can use 8-10mm .015 nickle, to connect the packs you can use 2x12 awg wires or 3-4layer of the nickel should work too. If you want to go with cell fusing than you need to use different nickel strips or fuse wires. It’s more safe but bit more work. If you interested search for cell level fusing in the forum. There some good explanations here
Thanks @Andy87 I think I get the idea now and I should be able to run individual packs of parallel batteries and connect them in series
Welcome!Just post your design when ready. Always good if other people double check it😉
@Andy87 I have drawn a rough sketch before and after balance leads. As I’m not sure if you have to attach them to positive or negative connections? If it makes a difference? Thanks for your help
Read through the thread here
Usually the leads connected to the + instead of the main -. If you buy a bms there should be a wiring diagram come with. They sometimes a bit different to wire up.I guess you still have a small fault in your drawing. You should go like this:
One cell is one block in your case and sorry for that bad drawing. I‘m in a hotel now and don’t have anything to hand
Ah and better use 10awg for serial connection. Just to be on the safe side. 12AWG is good for 41a, 10awg up to 55a
Once again thanks for your help and I appreciate your input. I know what you mean by not having any paper but I’m at work lol.
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Hi @Andy87 So that I understand what your saying I am correct with my parallel connections in a 3? But my series connections to connect them needs to be - to + on each?
Yes. The current should flow like an S through your packs. - + - + and so on. Or how else to say🤔from the upper left corner from your pack to the down right corner, then turn around the next pack and from the left down to the up right and so on.
Have you made a few packs before? I think I want to start completing my pack soon and would like some advice 
not so much yet. Till now only one, but I researched a lot here in the forum for my next build which will be a 12s 6-8p. Ask your questions and i‘ll try my best to give a good answer 
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Thanks, I will probably ask the question when I can on the battery thread
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Sorry @Andy87 I have another question for you lol. I was looking for a complete diagram to try and work how people mix the parallel and series on the same using the strips and I was confused how these work?
