First time BMSer, Is this wiring diagram correct?

ESK8 Electronics
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Hello all, I have been trying to figure out how to correctly wire up 4, 6s lipos into a 12s2p pack with a BMS

The Bms that Im using has instructions, albiet in chinglish so I am hesitant to just solder things up without getting advice first. Ontop of that each lipo has 7 balance connectors instead of 6 - 6 black cables, one red (turnigy graphene 6s 8Ah)

Any help you guys can give would be amazing!!

bms%20drawing p.s I did ask this twice on noob questions thread, but to no avail as I dont like cluttering up main chat with basic questions.

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Look up this thread everything should be explained there.

I‘m not lipo expert but I know that if you balance charge cells in parallel every single cell need to have nearly the same voltage and internal resistance. If not you can mess them up or in the worst case fire them up.

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I was under the impression that those internal cells should auto balance within the 6s2p. if this isnt the case, how would I get all the cells auto balancing. ?merging the balance connectors together so when they are charging they balance?

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not much help but you’ve made an awesome purchase with those graphenes, they’re amazing batteries

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Don’t want to say you something wrong, so better to call people with more experience. @PatRocks @deucesdown @Kug3lis @Namasaki maybe you can explain what to take care about if balance charge lipos?

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Thankyou, I was able to get them on sale for £45ea. I couldnt say no. even if it means stepping down from the 16Ah multistars

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oh they will be so so so much better than multistars

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P group balance connectors connect in parallel and series connect together there first negative side group last connects together with first positive side group first balance pin

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Like this:

58%20PM

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I think this is an overly complicated way to think about this. The phenomenon you’re talking about is explained by this:

If you connect 2 cells together in parallel, with slightly different voltages, the act of connecting them together will force them to be at the same voltage. Energy will flow from the “more full” cell to the “less full cell”. If you leave the cells connect together, this will happen all the time.

This activity happens at the cell level, not the pack level. It’s not automatic nor magical. You must connect each cell in parallel to get this action. For you, this means, you must:

  • splice each wire in the balance connector for 2 packs. This gives you a pair of 6s2p packs. Note, this is a 3 way splice, as you need a wire coming out to connect to the bms.
  • Then join the 6s2p packs in series to get 12s2p. The power leads will have to be joined in series. The balance leads, kug3lis diagram is perfect.
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Ahh I see your BMS has 12 pins and first of balance connector goes to battery GND just double check if first pin on your lipo is negative

18%20PM

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Ahh I see. that diagram is amazingly helpful!!

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  • splice each wire in the balance connector for 2 packs. This gives you a pair of 6s2p packs. Note, this is a 3 way splice, as you need a wire coming out to connect to the bms.
  • Then join the 6s2p packs in series to get 12s2p. The power leads will have to be joined in series. The balance leads, kug3lis diagram is perfect.

So the act of splicing the balance connectors together is what lets the cells self balance just by sitting / auto balance during charging. Then just wire up the two packs like normal for 12S and it should be good??

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One further clarification. With respect to self balanceing – the only cells affected are the ones connected in parallel. Series guys have to be balanced (if needed) actively by a balance charger or the balancing circuits in a bms.

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SO as long as All charging is done through the bms everything should be fine?

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The answer to this type of question must be earned through reading research and testing. :slight_smile:

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Fair enough, I do thank you for your amazing assistance! both you and @Kug3lis - I can finally finish the build!

The only other thing was the charging port location and polarity. but since no one has mentioned it Im guessing I got it correct!.

And Again, Thank you!

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Hey one more thing in your diagram on the bms you have “P+”. I think it’s really “P-”?

Okay I lied, another thing. You want a fuse (important), loop key and/or /switch?

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Your absolutely right, It should be P- My mistake!!

I Am definitely going to have a xt90-s loop key to interrupt the circuit. but also to isolate the Vesc’s while charging. However I didn’t consider a fuse. would soldering 5, 30A car fuses together in parallel do the trick, or should I look for a specific fuse of the correct rating?

Edit. Is a fuse even needed? as I see lots of people forgo one in favour of a decent bms and loopkey

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If you go with a fuse and 12s look for 58v fuses not the 32v ones

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