I have a early 80s ezgo resistor cart that i have upgraded all the cables to 4ga. I was hoping to add two batteries to get a little more speed out of it. My question is how do i go about wiring it so i can charge the 6 with the charger i have now and then charge the two with a seperate 12 volt charger. I was also wondering if i have to change anything else, controller, etc. Thanks