Help with wiring 12s BMS [Dead P Group, again]

Assembeling the batteries and wondering where do I attach the balance leads? Also my bms has 13 balance wires what do I do with the 13th?

Thank you all!

Check the diagram if available. Usually the first is for main negative and the rest for positive in specific order. The last one on main positive.


@thisguyhere hey bro I think i got this BMS from you do you happen to have a diagram for it?

Holdup, send u stuff in a min

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And what @anon54720240 said

How do I bypass the discharge on this?

So battery negative to here

And then I jump the p-/ch- to here?

Ok cool and that bypasses the discharge function of this bms?

Ok so basicly the two options at the top are for charge and discharge? So the one on the left is the one I want?

For discharge only

What @anon54720240 said ^^. I thought it was to battery positive on my first bms. Big blue arch. I had to rip the connectors off as they soldered themselves together. It was a scary experience. Smh. I felt very dumb that day.

Wait so where does the 13th balance lead connect to? The one on the very left

Still need help with this. Not 100% sure what to do with the last balance lead. It seems to me that it goes somewhere on the positive side but I am not sure

This is what I am confused about, looks to me like that red balance lead goes to the battery positive

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It should. If it’s a 12S with 13 balance leads the first one is usually a redundant ground connection. From there it’s just series 1-12 with the remaining 12 cables, starting at the first series and working your way up to battery positive terminal (connected to pin 13 on your BMS).

I think that @BigZwatt was referring to was the fact that most BMS use common positive and individual negative planes for B-, P-, C- etc, and he mistakenly plugged a positive mains into one of those (allegedly).

PS: Is there a reason you’re jumpering P- & C-? Something specific to your BMS? Not to say it’s wrong, just curious on the why


@thisguyhere hey bro is the picture I posted the correct configuration for a charge only setup?

in short, yes. but kinda confusing since load- and charge- are shown as same connection.

assuming you got the balance leads right, see if this helps


So this bms has 13 leads the last one is shown to go to possitive, this is correct right?

correct, extreme ends goes to Batt+ and Batt-