I have purchased a 36volt 20amp LifePo4 battery. It arrived with a charger that had a big female plug for attaching to the battery. It doesnt match any of the other connectors on the battery. Also the battery has one large gauge positive wire coming out and no negative wire coming out of the battery. The battery management system has two small gauge wires, one positive and one negative. Anyone know how to wire the battery to the motor controller and how to wire the charger to the battery? I appreciate all your help.

thats a difficult question.

are you sure the bms has a pos. and neg. wire; if the battery wire coming out is a positive maybe the bms wires are neg (charger) and neg (discharge).

if your bms is similar to mine then during discharge the bms provides low-voltage cutoff (based on each cell) and overcurrent cutoff and over-heat cutoff. During charging it does cell balancing and over-voltage cutoff. so the main negative wires to the charger and to the motor come from the BMS, which is connected to the main negative wire that goes direct to the battery.

I have purchased a 36volt 20amp LifePo4 battery. It arrived with a charger that had a big female plug for attaching to the battery. It doesnt match any of the other connectors on the battery. Also the battery has one large gauge positive wire coming out and no negative wire coming out of the battery. The battery management system has two small gauge wires, one positive and one negative. Anyone know how to wire the battery to the motor controller and how to wire the charger to the battery? I appreciate all your help.

I had a same experience and got some help at endless.

The charger connector you have is called 3-Pin Shroud Female (IEC C13) and its a type that is used for the desktop computer (or power connector). You'll need to find a male side of that connector or just cut that end and use whatever you want (I'm using an XLR connector).

As for the battery, look for any marking for power + and -. There's should also be a C-, which is for the charger. Otherwise, a pic will be helpful.

One thing I'm gathering is that either these BMS don't work properly or workmanship is not that high - so I' m getting a cycle analyst and/or monitoring the charge in the beginning with a volt-meter to see if these BMS are working properly. good luck.