Rooftop AC for 144' Sprinter Conversion

[alexk243]

Just purchased my T1N (04) Sprinter Passenger model and I am starting my conversion. The first thing I need to figure out it the AC and electronics.

I want the rear rooftop AC to supplement the front AC while driving (run of alternator) and be able to run when the RV is plugged in to AC shore line. If it could run off the batteries for a few hours that would be awesome, but not mandatory.

There will also be two roof vent fans and probably 200w solar setup. Once I figure out the right AC I think I can move onto inverter/battery setup.

Thank you guys in advance.

[Shearwater]

Why do you think you need a second A/C unit for when you are driving? I've never felt a need for a second A/C and most people who drive B's don't either. those that want it buy a generator to power it.

More important to controlling climate is insulation - figure out a good way to get proper insulation and you won't need an A/C while driving.

[alexk243]

Wouldnt a 5000btu system be enough for sleeping and driving in a 144" wheelbase sprinter? its only around 70 sq feet.

[Shearwater]

A typical 15,000 BTU A/C unit requires 2400 watts (Camping World info). Camping World also suggests a generator of at least 3500 watts to run that A/C.

Running that A/C with an inverter and alternator requires an inverter of at least 3000 watts and an alternator that ALWAYS puts out at least 200 amps even at idle. I don't think you can find a normal alternator that can generate that many amps.

It might be possible if you can find a 5000 BTU A/C for an RV but that is not much cooling power.

Before proceeding with this, I would strongly recommend doing a lot more research including checking out how engine RPM affects the power output of your alternator.

[the_bear_II]

I would look at the units truckers use in their sleepers.

[alexk243]

So the do not make an AC unit that can run off of an alternator and inverter?

[bsinmich]

If you are going to attempt to run a 110V AC off of the 12V the MH is putting out you will find a lot of problems. You will most likely be overloading the alternator of the vehicle and get shortened life out of it. If you have a generator on the RV that is what would be needed to run a 120V AC. If your idea was possible it would have been done by everyone building MHs. That is one of the prime reasons generators get installed.