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Discussion Starter #1
Hello,

I'm about to buy a 159" Promaster to convert to a camper van and have been trying to educate myself on electrical systems, A/C's, etc. I'm trying to figure out how to keep the rear of the van cool while we're driving down the road in hot summertime temps (100 degrees). I wasn't sure how well the the cab A/C would work keeping the interior of the van at a comfortable temp. If it would be enough, then my problem is solved. Would the cab A/C even come close to keeping the rear of the van cool?

If not, then I'm trying to figure out if I can run an A/C like the Coleman Mach 8 (with an easy-start installed) while driving down the road by having power supplied with an inverter and the batteries being charged primarily by the alternator. Is that a workable solution? Would I need to switch the alternator to the higher capacity version? Would a 2000W inverter be big enough?
 

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I'm in west TX and often drive in temps 100F+. Cabin air with Recirculation button pushed cools my insulated 159" in just a few minutes. Fan is noisy on High but thats a small price for comfort. Once cool turn down fan. I see no need to supplement the cabin AC.
 

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The key is insulation. If done well dash board A/C will easily cool it all when driving.

What are you going to do when parked? If not plugged into power a generator is usually necessary. Only other option when stopped is an enormous battery bank, second alternator, and automatic engine start.
 

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2014 3500ext Gas - VA
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1. Cab A/C is sufficient to keep the back of an insulated van comfortable-ish (approx 80F) in 95F sunny weather.... extra circulation by an auxiliary (12v) fan and/or ceiling fan with passive venting out the rear really helps knock the temps down after baking in the sun.

2. I selected the Mach 1 PS (lower static rotor draw), a 3000W inverter, and 440 AmpHr battery bank with the hopes I could run the AC for short periods off the batteries. The system "worked" but after seeing the current draw and impact on the battery bank, I rewired the AC to only draw off the shore-tie. After installing an extra start-up capacitor, my Honda eu2000i generator is plenty capable of shouldering the load (But not while driving).
 

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I have a 159 high roof crystal granite gray PM. The entire van is insulated with 2" of 3M Thinsulate. 70% of the roof is covered with solar panels and 1 fantastic fan. The back doors have factory tinted windows and 2 after market windows on each side with heavy tint. Last summer I drove all day in temperatures 102 to 109 degrees and the factory front air conditioner was able to keep the entire van cool. I would leave it running at fuel and lunch stops. When I stopped for lunch in partial shade with the outside temperature 106 it actually got to cold and turned the fan speed down to med/low. The rear of the van would be slightly uncomfortable and the center of the van would be comfortable at high noon. I don't have window tinting on the front windows or the wind shield. I have read about a nearly clear wind shield tinting with a reflective quality that helps tremendously with heat absorption.
 

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Discussion Starter #6
Thanks for the info. I guess on the A/C while parked we'd either use shore power or a small generator. My unknown was keeping it cool while driving since we tend to only go to cool places (NM, CO) in the summer and go the the hot places (south TX, etc) in the cooler months or go to the Mtns in winter to ski. Getting from OK to NM mid-summer means driving for about 8 hours in the heat until we get to where it's nice and cool. If it was just me I'd be ok but if one or more of my kids is with me they wouldn't have much fun if the back of the van was an oven all the way there.
 

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2014 136” HR
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I know exactly your dilemma. We are in Ponca and that stretch is a chore, especially at 100°+. I've got excellent insulation in my 136” where it's insulated, but I've got some bare metal and full-around uncovered windows. Thermometer is on the driver's side C pillar. There are just two of us, so we point the vents our way and we've never worried about the temp back there, but I do check. it is never hot back there. If you point vents their way, I don't think you will have an issue. Next step would be a 12v fan.

Do you know the campground in Ellis, KS? Cheap, fully shaded, electric, showers. We carry one of these:

https://www.amazon.com/Stanley-6557...coding=UTF8&psc=1&refRID=RYEWET90VGNBF1QKF7TS

and wake up to this:

 

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2014-159 HR in CT
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Compartmentize the van hang a bed sheet behind were the kids sit and add one or two 12-Volt Oscillating fans.
That actually works pretty well. I used a moving blanket from Harbor Freight. It's thicker and adds some insulating quality....about $8. For the two of us, it goes right behind the seats.
 

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For additional cooling of the rear there is, for example, also a Webasto solution that integrates with existing A/C system, product name is BlueCool Drive 40.
It works only when the engine is on and is a 12 V system.
https://www.webasto.com/int/markets-products/recreational-vehicles/

Other solutions from Webasto are the 12V (or 24V) rooftop or integrated A/C system.
https://www.webasto.com/gb/markets-...ated-air-conditioning/integrated-ac-40-59-kw/

Some of the products has a maximum power consumption at 12 V that is not too high so to be battery operated, at least for several hours.
For example there are several units that have a maximum power consumption < 10 A at 12 V).

note: the links are to UK websie since the on Webasto U.S.A. website were not working, at least from my browser.
 

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Discussion Starter #11
Do you know the campground in Ellis, KS? Cheap, fully shaded, electric, showers. We carry one of these:
Nice picture MsNomer. No I haven't been there. We usually go straight west through the TX Panhandle into NM then go north.
 

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Our 3500 finally arrived! (gas version) & now there are about 3 weeks left to finish high-priority changes before leaving on our first long road trip. One of our questions is also about air conditioning while traveling. This van was selected for camping and travel with two hoomans and two big, hairy dogs. RVs have too much "stuff" for our purposes, so we are adding limited cabinets and services. AC & DC distribution panels have been selected, as well as the inverter, converter and batteries. With the very warm early spring, its dash air has been tested, & we will definitely need to run the roof air unit while traveling or have rear air installed. It was ordered pre-wired for rear air and with the 220A alternator. I've been wondering whether the alternator would keep the batteries charged with the roof air at a medium-low level, or whether a generator should be added.

This is the generator that we are interested in: http://www.fabcopower.com/generat/bgen.htm. Since it's a part of the engine, for elevations where it is recommended that you turn off vehicle air conditioning to reduce the risk of overheating, would an engine-based generator also need to be off (turn off roof air) for the same reason?

Was hoping someone with electrical knowledge could share insights.
 

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We're also trying to work out cooling the rear area for long drives. For us, this will be essential, not just comfort due to the needs of our passengers.

We have the 220A alternator, but for minimum air conditioning needs of approx. 2345 watts, it doesn't look like this would keep the batteries charged. I'm very new to these calculations and would be happy to be wrong if someone with knowledge and experience has a different opinion.

The other option is an engine generator. We are looking at this one:
http://www.fabcopower.com/generat/bgen.htm

It would meet the energy requirement, but there are still some areas where the grade is long and steep and signs recommend turning the air conditioner off. So with an engine generator, there would be no air conditioning during that time. I think for 20 or 30 minutes, that would be OK, even in the desert, so maybe this is the better option.

Other threads describe running the generator while driving to run the roof air conditioner. And the remaining option is to add a rear air unit. There are a couple of sources. The most popular one, with a unit that fits in the overhead area of the Promaster, sounds ideal, but I haven't been able to get a call returned. So availability and skilled resources may be an issue.

Would appreciate any input.

The Bigfoot Club
 
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