I was tempted to post this in technical chatter since it is semi technical, but on the other hand, it's like a yarn you spin over the campfire so I'll leave it to the judgement of the moderators to move it as they see fit.

Since I am building my P38 camper I was looking into the possibility of running an AC whilst stationary. There are dometic roofmounted so called "no idle" units available on 12volts and the trucking industry has some "behind the cab" units as well. They appear to be able to run on 20amps in eco mode and weigh around 30kg. Any truckies here that have experience with such units? In particular what they actually use power wise and what the duty cycle might be during a hot night?

In any case, adding an extra 30k's (and money) for a AC that is only used when stationary, putting a large lump on the roof where I want to stick solar and what not, etc. I ruled out such units. Some people have mounted very small split units to their campers but that is again extra weight and even less efficiency due to the added inverter that is needed. After some searching I came across a thread on here a couple of years back about the rencool pump. After some further research I believe it to be possible to replace the belt driven pump with one of those electric units without having to replace anything else. I do have some questions that pop up.

I wonder if:

1. the cooling capacity would be insufficient during the day whilst driving
2. the drain on the battery would be too high during the night whilst stationary.

It has to be said that I do not care for power usage when driving since I upgraded my alternator to a 200amp model rated at 100% duty cycle. Also, it does not bother me that the car would take longer to cool down after being parked nor is it a big problem that it would not reach 20c when it's 42c outside, 25c is fine as well. The insulation of the vehicle will also improve drastically since the rear is to be cut of and turned into an insulated box (camper) without windows. Only the front windows would remain not insulated but would be covered up when parked (though at night this does not matter much perhaps).

My intention is for the system to be sufficient whilst driving through very hot area's and to have some cooling during nights of extreme heat or humidity. Whilst scouring the internet for answers to my questions I have come across AC calculators for houses and when I put the numbers for my very small space, with poor insulation in a very hot climate into a calculator I would need 7600 BTU which is close enough to what the MD18 can provide. My personal experience with a house mounted AC is that during hot nights in the summer the AC barely uses any power since it only needs to cool some warmth creeping in, in comparison to the sun blazing on the roof etc.

Since I live in a damp relatively cool country there is no one around with any experience so if anyone here has some AC experience/input that would be much appreciated!

Cheers,
-P