Wiring new BMS

Joined
May 10, 2021
Messages
4
I watched a few Youtubes from what I can gather all the red BMS wires go to the positive on my battery the old BMS was wired to the negative I was going the splice the wires to new BMS, so I would not have to solder anymore on the battery

IMG_2713.JPGIMG_2714.JPGIMG_2715.JPGIMG_2716.JPGs-l1600.jpg
 
Did you know that you're missing a spot weld on one of the cells in the last group? Also missing a balance wire. Thats' in the lower right side of your picture. Is there a wire dangling out of your balance connector. The picture of it is hard to read. Is it half black and half red wires?

I suggest you show a picture of the other side of the battery, as well as a better picture of the old balance connector. If it is as I suspect, you can just wire the new balance connector to the old one, and also repairing that broken spot weld and missing wire.
 
For the Daly BMS:

The large main wires are to be connected to the negative side of the battery.
Blue wire (B-) goes to the battery.
Black wire (P-) goes to the output (i.e motor controller).

The balance leads connect to each cell string. The first one (black) connects to the negative end of the battery. The rest (red ones) connect to the junction between the cells series in sequence until you reach the positive end of the battery pack.

Hint:
Use a Multimeter to check the voltage on each pin of the balance connector. Between the black wire and the first red wire that voltage should be between 3.0 and 4.2 volts. Keep the multimeter lead attached to the black wire ground. Each of the red wires should increase the voltage reading by somewhere between 3.0 and 4.2 volts.

Example:
Black and first red wire: 4.0 volts
Black and second red wire: 8.0 volts
Black and third red wire: 12.0 volts
Black and fourth red wire: 16.0 volts
....


Missing connection ...mossomg.JPG
 
Sorry I forgot to mention this is a replacement battery that needs to be soldered when I do the BMS.
Just thought it odd as all the BMS installs I saw on YouTube go to the positive, but I guess it does not make any difference.
I was going to splice the wires close to new BMS with good insulation the socket is not interchangeable, seems easier also not having to put heat on batteries

Thanks
 
The balance leads connect to each cell string. The first one (black) connects to the negative end of the battery. The rest (red ones) connect to the junction between the cells series in sequence until you reach the positive end of the battery pack.

If you notice on this battery all the balance leads are connected to the negative groups, does that make a difference?
 
Except for the bottom cell group. every negative end of a cell is connected to the next positive group, right? So it doesn't matter whether you put the balance wire to a positive or a negative.

So if you connect the black wire to the first negative terninal, you could connect the next 12 wires to negative groups, but the last one #13 has to be on the last positive terminal.

In the you tube videos, they must put the black wire on the first negative terminal, Then the 13 red wires can go to the positive terminals in sequence, Easier for people who don't understand the wiring to follow. Better to understand why each wire goes where it goes, Hope this helps.

From my point of view, for your battery, I would would rather solder each balance wire like they did, in between two cells on the negative metal strips. That because there's nothing under the strip that will short circuit if I do a sloppy solder. If I move down the strip to the positive terminals and do that, there's going to be the steel negative side of the 18650 can right under the solder joint, only protected by the cardboard ring and mylar film. Screw it uo, and you have a short cirfuit I can't easily stop. Fire. Explosion. End of the line.
 
Not sure where these wires go to the battery and BMS
 

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