Battery and BMS connection questions

[Alan Quay]

Hi all,

I hope someone can offer some advice, as I'm not that familiar with Lithium batteries and BMS's.

I have a lithium battery here that I have taken apart. The connections are as follows:



Before I blow anything up, can anyone confirm my assumptions:

1. Battery output is via the the thick Red/Black pair.
2. If 1 above is true then BMS must cutout on negative side.
3. Charging must be via thick black and thin red, via thermistor.
4. What is the thin orange for?

Appreciate any input,

Thanks

 

[trex]

The thin orange goes to the negative side of the charger.

 

[Deleted member 4366]

BMSs usually do the switching on the negative side. Without seeing the PCB, it's difficult to say what the orange wire is for. Normally, the BMS has two separate connections for charging and discharge on the negative side marked "C-" for the charger -ve, and "P-" for the power out -ve. Some BMSs have an output to a switch that can switch off the battery as a master power switch, but all that I've seen had two wires to the switch.

Depending on the rating of the BMS, and assuming a 10aH battery, there's typically one FET for charging and maybe three FETs for discharging. If your bms doesn't have the "C-" marking, see if you can trace the orange wire to the charge FET. The black wire will go to the three discharge FETs, which sit in parallel, so have a joined output. A photo of the PCB would help.

 

[Alan Quay]

Thanks all, I'm pretty much convinced orange is charger negative. Will see what results I get with a meter, and probably remove the circuit board to be sure.