Building another battery pack

So the 12s15p battery pack is done and just waiting on a new motor. Now I’m making another pack for a higher voltage setup. 14s12p using Sanyo 20700B cells. My favorites!

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Oh and I also built a battery pack for my skateboard as a test. 12s4p with Samsung 30Q cells! My board does over 31 mph now! :joy:

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you should use some fishpaper or another, thicker, dielectric paper between balance wire tabs and batteries. your skateboard will vibrate and shake, and there is big chance that tab will cut through kapton tape and pink battery insulation and you will get short and fire.

I did

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That doesnt help, you have to have it around each P group seperatly. This way still first cell of P6 can rub at last cell of P5. Since PVC is thin and not really good at constant mechanical stress sooner or later there will be contact between cell housing of cell last cell P5 (wich is something around 18V) and cell housing of last cell of P6 (which is something around 22V)…when this happens you will get to know by some nice noise, smell and sparks.

Yeah I didn’t isolate the pgroups in the staggered formation. I guess sparks it is!

An easier way is to just weld the tabs for balance wires to the negative terminal. Then even if they cut through any insulation there will never be a short.

@Jezza exactly! But @tylerclark has his tabs already welded, it would be easier to just add fishpaper.

@Giga it would be better to add fish paper between each group, but @tylerclark has his battery in two layers, and there is glue between each cell + welded strips between series, so I guess there is very small chance that there will be short in that place.
I do believe that almost every connection between series should be flexible wires instead of nickel strip, so battery will have some flexibility and there won’t be so much strain in nickel. And of course, fishpaper, always fishpaper!
This is how I do it:


Your work looks sleek and durable. Would you have a video showing the global assembly cycle by any chance ?

If your question is for me, no, I don’t have any video. I need 4-8 hours for one battery, a little bit to long for video :grin:. I could post detailed photos step by step of next battery that I am building, 12s5p for electric skateboard.

Also, I will not use fish paper between groups in my efoil battery. I will build 14s12p battery, and cells will be glued in shape of block, which means that most cells will be glued on all 4 sides, and that should be enough for battery to stay in one piece forever. Other than that, on water won’t be so much vibrations like on streets.