#1 You need 12 volts.
#2 Large Alternator, I would go with 100 amps.
#3 Insulate every thing everywhere.Bubble wrapped foil works well.
#4 Do not expect much cooling past the front two seats unless you add a evaporator in the rear.
#5 Paint the truck a light color to reduce the heat gain and see #3.
#6. 235 or larger engine.
#7. Large radiator and electric high volume fan.
All of the above make for a trouble free system well built & designed system.
