12 volt a/c

[gradylaw]

I ran across this website for a company that makes self contained roof top air units which can run on 12 or 24 volts. Never seen one or heard of it on an RV. Does anybody know if they work? It would be nice to have cold air without the noise of a generator or have to plug in some place.



http://www.dcairco.com/

 

[Jumbo Jet]

You would still have to have something recharging your batteries at a high rate. The 9,000 BTU A/C (the largest model they listed) would not cool a small trailer on a hot day and consumes almost 40 amps. That means a large fully charged battery would drain below supply level rather quickly.



There's just no free lunch running an A/C in a RV.

 

[gradylaw]

Guess I'm always looking for a silver bullet. When I saw their claim that two 200ah batts would run the thing all night, I thought it sounded cool . (pun intended)

Thanks for the reply.

 

[Casey Balvert]

If it sounds too good to be true it usually is. I agree with Jumbo. Even the small units will rapidly drain your batteries and not adequately cool an RV. You might look at evaporative coolers but I am not sure they are really worth the effort. They use water evaporation to cool and work fairly well at low humidy levels. The concept has been around for many years but you don't see them advertised much any more. One thing we use in our fiver which I found makes a lot of difference is Fantastic vent fans. These exhaust warm air out of the ceiling vents. We have two of these units and they draw one amp each on low. Would not be without them and I can run both for three days solid and still have enough power left over for lights etc. I have a 450 amp hour bank although realistically I can only draw 360 amp hours. Seems battery manufacturers are as optimistic as my money manager was five years ago.



Casey

 

[J D Moore]

Bill Swails has 12-v AC in EarthRoamer, which is very well insulated and relatively small compared to the average RV. You might check with him.

Jim

 

[gradylaw]

I have an email into Earthroamer. Haven't heard back yet. My truck camper is relatively small also. That's why I was looking for somebody with first hand experience. But at $2,400. 00 bucks, I think I'll settle for a good ol' Coleman and my generator.

 

[Prairie Dog]

The evaporative units (we call them "swamp coolers") work very good and draw very little power, but you have to be in a very dry environment. I don't think they'd do much in Texas.

 

[gradylaw]

FYI --- Got a reply from Bill Swails re: this subject:



"The 12 volt AC did not work out. It was no where near 13,000 BTU, was noisy, and quit working after about a year. I'm evaluating another AC option and if it works out, we will be selling it via our web site in the next couple of months.



-Bill Swails-



EARTHROAMER.com LLC

Live your dream!"



I am hoping this is new technology that will soon have the bugs out and eliminate campers need for 110 volts to keep cool.

 

[EarthRoamer]

Cooling an RV with battery powered AC is a difficult problem. First, most RVs are poorly insulated and require a large air conditioner. Second, all RV air conditioners that I have found (except the Airco) are very inefficient. In the US we rate airconditioner efficiency by EER which is simply BTU of cooling provided divided by watts of electricity used. Airco has a claimed EER of 12. 6 which is probably a good number. I can verify their 350 watt power consumption, and their claim of 4,420 btu of cooling seems reasonable. Third, most air conditioners run on 110 volt ac current and energy is lost when we invert 12 volt dc to ac. Finally, most RVs have limited battery power.



In the new expedition camper we are currently building, we address all of these issues. First, the body of the camper is molded to form a one piece fiberglass/foam laminate shell that is strong, lightweight and is a good insulator. Two, we are using a highly efficient air conditioner. Three, we are using an efficient inverter. Finally, we have a big battery bank of the highest quality batteries available, and we have the means to keep them charged with dual alternators and big solar panels.



I'm in total agreement with you regarding the drone of a generator; that is why we have chosen NOT to use a generator on our expedition campers. The Sunny Airco 1300 I used for over a year was quite noisy when running, and the 4420 BTU of cooling wasn't really enough even with my relatively small camper. Check our web site in a few weeks to see how the new system is working.