holy bananas, that is confusing… how do I change this wiring schematic if I want bypass the BMS for discharge?
I’ll draw up something easier to understand.
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Thanks dude. I really really really appreciate it.
I’m getting around to the wiring diagram right now. How many balance wires do you have on your battery?
Untitled drawing.pdf (29.4 KB)
If you battery has 12 balance wires, you will need to wire in that redundant negative that I mentioned. If you battery already has 13 balance wires, just pair them up to the BMS connector and your good to go.
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Thank you! For the diagram
Just ordered a 30amp tonight for bypass. Also picked up one of the waterproof red ones (non bt)
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Dude. It is hard for me to express how much I appreciate this. I have been freaking out about this step. I am not home right now to count but if I recall there are 13 of the little cables.
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No problem man. At first I struggled a lot to understand this, so I’m happy to help you through it.
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Dude… It is alive. That is so freaking cool to see what is going on with the battery on the app.
Thanks again for all your help.
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Yeeeewwww! Well done dude!
Hi Guys, is this good bms? 6S 24V 15A 20A 30A 40A BMS Battery Management System PCM PCBA 18650 accessories for 18650 Lithium Ion Battery Pack With Balance|Battery Accessories| - AliExpress
its balance detect voltage 4.18 but over current detect voltage is 4.25. Will this be good for 2* 6s batteries(i have them sedately) resulting 12s with 50.4v charger? Will it stop charging at 4.18v?
im bypassing bms for discharging btw
Theoretically, you could charge both 6s packs in series, with their own bms’s, with a 12s charger, but that doesn’t seem like a good idea(and I’m not sure if you can actually do that with setting everything on fire). If you want to charge the packs together, use a 12s bms and a 12s charger, and make a wiring harness to adapt the two 6s leads to the 12s one that goes into the bms. If you want to charge them separately, you could use two of the bms’s that you linked, and charge them one at a time with a 6s charger.
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Thanks for response,
i have to use 2x6s because dimension restrictions of my case. Therefore i came up with 2x6s bms and not 12s. As i cant wire 12s bms across all board
Any suggestions?
If my initial pay sounds like a fire to you i can theoretically charge 2x6s bms separately at same time with 2*6s chargers.
I came up with initial plan to reduce risk of uneven batteries in first and second 6s group. to make charging as simple as possible. But if it will do the opposite i can charge separately with 2 chargers at came time
If its clear to you witch is better, please give an advice)
How I would do this is run balance wires from one battery over to the other side. It only adds one more thing that you have to run on the bottom of the deck. Then you can use one 12s bms. The long balance leads shouldn’t be a problem.
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This drawing doesn’t include a power switch or charge port, but it gets the idea across. Depending on which enclosure has the bms, different wires would have to cross the middle of the board.
Well, I did not thought about this.
This will add a bit of complexity as i would need to add wires for balancing, and for charging itself.
But this can be achieved. I’m worrying about about increasing complexity and therefore reliability.
Image not representative, im gust imagining 2 batteries and added wires between them
So basically at this point there is 2 possible solutions:
- charge 2x6s batteries separetly at the same time with 2 chargers
- Use 12s bms and add wires to other side of the board for charging and balancing.
Is there any obvious highlights on witch approach is better?
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IMO the one BMS approach is the way to go. Here’s why:
- Adding an extra BMS is just adding another thing that can fail
- If you put the BMS in the same enclosure as the vesc, you would only have to run one more cable(6 balance wires) along the top/bottom of your board.
- Saves cost – you only have to pay for one charger and one bms
- In the end, it is simpler. It may take a little more time to understand how to wire up, but you have fewer components and fewer wires to deal with.
Thanks for your advice. Im a bit confused
If ill put bms in same enclosure “i need to run one more cable(6 balance wires) along the top/bottom of your board” AND positive and negative wire for charging(as existing wires is for discharging and switch(Anti-Spark XT-90S Loop Key) is located at opposite side of the board and i cant use them.
Because bms cant charge through balance cables it only balances, and this needs charging cables as well. Isn’t it correct? Is this ok for bms to charge in this way? To me looks similar to my initial plan with 2x6s in series making it 12s