36V Lithium Charger Smokes. Somethings not right!

[DouggieFressh]

Would love some advice. Just want confirmation on whether I'm the idiot or if this charger is faulty.

Setup:
3x12v 100ah dakota lithium batteries wired in a series.
Renology battery meter.
Dakota Lithium 36v 8amp charger.

Positive Terminal - three cables

1. Main power cable to the golf cart
2. charger positive cable
3. combination cable of 12v reducer and positive to the battery meter.

Negative Terminal - three cables

1. Main negative to the golf cart
2. charger negative cable
3. combination cable of 12v reducer and negative to the fuse panel

The first sign of an issue was when I was wiring everything together. I had the Anderson connectors together and attached to the charger. No power to the charger. I connected the positive terminal to the charger - no issue. When I went to connect the negative cable to the negative terminal it shorted (heavy sparks flying). A little smoke came from the charger. Knew something wasn't right.

Tried a second way. Disconnected Anderson plugs. Connected the charger to the battery. Tried to connect the Anderson plugs. This time a pop and smoke from the charger. Disconnected the Anderson plug and am not touching it again....

Did I wire something wrong to cause this? Or is this just a defective charger??

Otherwise, everything works great. I balanced the batteries before installing them and with the charger removed from the loop everything (accessories, headlights, and golf cart) works perfectly and the cart performs like a dream.

Appreciate the help!!!

See picture below for setup.