Anybody running more than 4 batteries?

Need some electrickal help...............

 

I built a rack behind the cab, that can hold up to 6-8D size batteries. The truck is used to pull a 34ft fifth wheel travel trailer so weight was not a concern. I have installed a 4000-watt power inverter on the truck that is connected to these batteries. It gives us enough power to run the central air in the trailer. The battery rack is isolated from the cranking batteries by using a continous duty JA solenoid, available at any golf cart parts house for about $24. Rated at 600 amp continous. The solenoid is connected to the key switch. It offers more cranking amps for cold weather starting, but protects your cranking batteries.