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Discussion Starter · #1 ·
Greetings to all.

I am new to the EV world and I am starting on my electric motorcycle conversion. I acquired some a123 26650 batteries, used, but in good condition still. They were built in packs of 40V for electric buses.

Anyways, I am planning my pack design as I have almost all of the components to start building the pack.

I have attached the layout of what my thoughts were. With my tight dimensions I have with my bike, I am doing a 28S 17P pack. I am more concerned about the individual connections to make sure I have the right concept.

Please let me know your guys thoughts of what I can do. I am doing 17 "layers" of the 28 cell blocks. a 4 x 7 block is the 28 cell block layer so to say. The top view is what each block looks like and have those stacked 17 times to achieve my desired dimensions.
 

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Discussion Starter · #3 ·
The middle block has them wrapped like a snake where the positive end is on the top left corner and the negative is the bottom right. making the 4x7 area a 28S if I am looking at it correctly. The attached document may help as the green is the series connection, the teal is the parallel connection and then you have your positive and negative leads off the ends.

The BMS I have is ZEVA modules. I have 3 of the 12 unit modules only using 28 out of the 36 available spots for this configuration.
 

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Discussion Starter · #5 ·
Yes that makes sense and I just realized that mistake. Thank you for clarifying. I have updated the drawing with attached document. Could I basically make one large layer of 28S 17P and have extra nickel strip for the fold where the dashed lines are? In between each fold would be an insulated, non-conductive material to prevent shorts. Then have the bms wires attached to each 28S row essentially.
 

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Discussion Starter · #7 ·
That was my next step was for the framing of the module. Once I fold the pack, I'll make measurements to make a cage like structure around it with either angle iron or some other fabrication method. I appreciate the feedback as well greatly! Building larger packs come with a lot of complexity when you break it down by any means.
I also heard of the a123 26650 battery cells I am using requires a vent when spot welding the tabs on? Is this true or?
 
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