quick update
I put a roof vent in the van and what a difference it makes as far as interior air flow and removing stagnant air. I'm very glad I decided to do it. It brought my day time temp down about 10-15 degrees when all windows are closed with vent open, If I crack the windows and turn the exhaust fan on it's no different than outside air temp. It creates a nice vacuum, puling fresh air in and pushing hot air out. I was a little concerned about being in the desert with a black van but not anymore. I used the FANTASTIC 2way 14" vent, lifetime warranty.
I was having trouble with charging my house batteries and now I know why. The previous owner must have had the wrong solenoid installed,(left) $18. I replaced it with an identical unit which is mounted under the battery in engine compartment once and burned out again. I needed a
continuous duty cycle solenoid (right) $75 now the house batteries are all charging nicely. Took me a while to find one that worked.