Connecting battery balancing cable to the bms

I guess I didn’t specify this when describing battery requirements, but long story short, my battery has balancing cables designed for smart lipo balancing chargers. Here’s the balancing cable with explanation:

Meanwhile BMS expects 10 wires:

How should I rewire it so that it would be compatible with the bms?

Ignore 1 as it’s pack negative. 2 will be 1, 3 will be 2, 4 will be 3, and so on.

However, even with any advice (including mine) you’re given on here, please make sure you probe the header with a multimeter to verify voltage before plugging it in.

1 Like

So red (last wire) is 10th balancing cable on the bms?

Should be. Use a multimeter probe and hold the black (neg) to battery negative. Use the red probe to probe each wire on the header. It should go up by multiples of about 3.8v~ starting at 3.8v~

1 Like

Ahh, that explains it, I was weirded out that all balancing cables are negative and the last one is positive. And yeah, first and last cables provide full pack voltage.

Whoever made the battery just didn’t bother to color code the cell wires. Either way, “Trust No one” Do as Master Jinra said and test the voltage of each wire.

1 Like

@Jinra @karosass1 I get what you guys are saying about forgetting about the 1st black wire, but I still don’t see how it will plug in. If the balancing cable is “11” wide and the BMS port is only “10” wide, how will it fit? I am just curious because I am planning my first board right now and I think I will have the same problem and I just want to make sure that I understand it.

you need to get a 10 pin header of of the correct JST variant/pitch and use a pint to take out the wires from the header to place into the new header.

Are you saying that he can use 10 of the 11 wires but has to get a new end that is 10 and not 11? So, wouldn’t it have just been easier to get a JST that had 10 to begin with?

yes, but if the battery comes with an 11 pin connector, it’s easier to get a 10 pin connector.

you can always pull a me (not recommended)

and cut the connector

1 Like