4 First locate your positive post (where your power goes to the solenoids), in this case 48 volts, which will be the fourth battery from the ground. Next, take the positive clamp (Red) from the charger and attach it to the positive post. Then locate the negative post on the bank. (This would be the post with the quick disconnect that goes to the battery rack or frame on the car). Attach the negative clamp (Black) to the negative post of the battery bank.