How does one determine orientation of Balance Lead Connector?

[whatismouse]

I'm a little paranoid to make this connection after having done it wrong before. And of course I didn't note the orientation when I disconnected recently for other purposes.

So I'd like to know definitively how to determine the proper orientation of this (and any) balance lead connection.



It would also be cool to know what the function of all these different color wires are on top of my A123 battery. They all seem to route into the balance lead, but they seem to route randomly into the plug in an order that I don't understand.

 

[MrNatural22]

If you look carefully at the wires, those are the balance wires and are labeled on each wire which cell they lead to. The others are temp sensor wires there are three sensors, one on each end and one in the center.
I went a different way on mine and cut the plug off. Removed the 3 temp sensors and wires because my overkill BMS has its own dual temp sensors which I placed on each end. I then soldered the corresponding BMSs balance leads to the correct battery leads. Just my preference for a clean BMS install.
pics on post # 77?

Big Battery 24v A123

I went with this Voltage Range: 20V – 28.8V -- https://bigbattery.com/product/24v-a123-lfp-battery-free-shipping/ That means 2.5 volts per. If dead empty is actually 2.0 volts then I would want to see the discharge curve to find out where the knee is. I don't disagree with 3v, but I'm just...

diysolarforum.com

 

[whatismouse]

I'm massively confused. I have two batteries here, one with a BMS hooked up from the factory, the red wire on the 8S balance lead corresponds to the S8 side of things on the battery side. But the image on the BMS itself, red corresponds with B1, which seems backwards?




However on battery #2, red corresponds with B8 (see picture in original post). So the BMS' are opposite each other, and the one that I know to be correct would appear to be opposite the chart on its respective BMS...

 

[MrNatural22]

Puzzling, you could call Bigbattery and see if they can explain. They are pretty responsive when called.
It was a little more work but, I liked the functionally of the Overkill BMS BT and user settable parameters for the same $$.

 

[whatismouse]

support from bigbattery has been hit or miss. But I did get it connected, and nothing smoked, so it must be right. Its actually the connection at the BMS side on the complete pre-assembled pack that is most confusing to me, since it seems like the diagram is incorrect.

 

[whatismouse]

One thing I found confusing is how all the balance leads route into the plug itself. There was kind of enough of a pattern that I could guess which side B0 should be, and which was B8, but they also were not exactly in precise order. And then trusting that the diagram on the BMS itself was correct was a total gamble given that the other one was not...