How do I run a standard window A/C while driving? Adding dash A/C?

[drummertom]

Sent: 3/13/2006 7:19 AM

Hi I just purchased my first, as I have mentioned in a couple of other posts. It is a 73 Brave. Since it doesn't have dash air, and my wife is very hot natured, I would like to figure out if I can run the cabin air while traveling and what is the best way. (OBTW) The cabin air is a window unit mounted in the rear, as the roof unit doesn't work. Is it practical to run the genset while driving, or would an inverter work? Anyone tried to add dash air to one? Thx for all of he info.
Tom

[Oz]

Sent: 3/13/2006 6:53 AM

If you use the keyword: A/C in the message search, you'll come up with some of the info you are looking for.  Basically, adding dash A/C isn't worth the trouble as it would be difficult to find a running unit to add, could be costly, quite the installation challenge, and they don't work very well since this small unit has to fight all the hot air coming from the entire coach.

I also was wondering about running my roof A/C while driving using an inverter, but the responses were that the draw from the A/C unit is too great for the alternator to keep up with and it would suck the batteries dead in no time at all.

The one option that would work is to run it off your generator.  Unfortunately, I never had one myself so I'll leave the wiring portion up to the pros.

If not for the time factor I was facing at the time, I would have replaced my dead Coleman RV roof A/C with a conventional house unit and mounted it on the roof.  I Could have saved a lot of money by purchasing a used house window unit.  Heck, last year, my wife found a one year old, 12,000 btu unit at a yard sale... complete with remote control for $100 (The people had just installed central A/C)!  I had already thought out the design and process but, under pressure from the Queen to go camping, I ended-up buying a new, Carrier V 13,500btu RV roof A/C on sale (my project would have totalled less... and I really wanted to do that... you know... the "man thing").

The mounting and ducting wouldn't have been difficult, nor finding or making a suitable cover for it and the wiring is already there!  I just would have either ran extension wires from the controls, or gotten one with a remote (like she found).

You may want to explore this option.  It's fun to create unique ways to solve problems and puff your chest out and say, "Yup, I did that myself!"

[denisondc]

Sent: 3/14/2006 10:08 AM

It is very likely you can run the cabin air unit while driving, using the genset, but with a couple of things to think about
* Personally I don’t think any Winnebago wall structure was made to support a window unit hanging out of a window frame. I don’t know the long term result, but travelling down the highway will involve some bouncing and twisting of the window frame as well as the down-weight. . If it is a 5000 btu window unit it would probably draw about 5 or 6 amps, and weigh over 40 lbs. A 12,000 BTU unit would probably weight about 90-100 lbs. I have seen RVs on the road with a window unit, but I also recall having seen metal frames supporting the unit. I would plan to support that window unit with a brace that distributed the weight of the unit over a distance as large as I could - like lightweight angle iron (or aluminum) that went from floor to ceiling, and held the outer casing of the window unit. When the RV is parked, I imagine the window frame itself would hold the window unit up well enough. I have had to slice open the sidewall of a Winnebago in a bone-yard, to haul out a used fridge (there was another RV totally blocking the entry door). There was -nothing- to that wall except 1/8th inch plyboard on the inside, an inch of blue Styrofoam, and the .027" aluminum outer skin. The back-walls might have some thicker plywood in their makeup, but I don’t know.
* The window unit may not make the inside much cooler anyway. Our roof a.c. unit is the typical 13,500 BTU size, and works fine when we are parked. We have tried using when it when we were driving, powered by the genset and it was about 90f outside (in the shade) and sunny. The RV was not in any shade of course. I could not tell that if felt ANY cooler when driving, compared with having the windows open and drinking plenty of fluids. There are just too many sliding window joints, door joints, etc. for the inside air to stay inside. But with the side windows in back open, and those beside the front seats open, you get excellent airflow, without buffeting, that feels pretty good. The eyebrow keeps you from being in the sun, and the air is going out past your face. I have an air cushion thing I put on the seat, and a water sprayer, for the times when the late afternoon sun is beaming on the side of my face. We drove around southern New Mexico and Arizona in July once. Yes it was hot, but we didn’t suffer - two adults and 4 teenagers.
* As for using an inverter…. If it is a 5000 btu window unit it would probably draw about 5 amps at 115 volts. At 12 volts, the inverter would need to draw about 50 amps from the batteries (it would take several) and still you would need to be recharging them as you went. The alternator was not designed to supply this much power continuously, and certainly the existing wiring from the alternator was never meant for that much current. Driving at night with the outside lights on, the alternator is probably already providing a steady 16-20 amps as it is. If your window unit was larger than 5000 BTUs, it would take proportionately more than 50 amps from 12 volt batteries. Our 13.5k roof a.c. draws about 11 or 12 amps when running. Starting current is higher of course. It weighs just over 100 lbs. Our roof a.c. died one summer while we were on vacation. We kept checking prices as we drove southwest each day from Tennessee to South Texas that August, finally buying one in McAllen TX for $500 with installation. The a.c. is Really Nice to have for sleeping. For use while driving - not workable as far as we are concerned. The a.c. units that run from the engine have greater cooling capacity than a mere 14k BTUs, probably more like 20k BTUs. There are after-market units that can be installed, but it takes some engineering. A local RV repairman here in S. Texas quotes $1600 for parts and labor, but admitted that it is usually higher ($2000) - if for example the brackets to hold the compressor arent available for the particular motor in your RV, etc. Often the installation involves radiator cleaning/recoring, along with other upgrades to the existing cooling system, since it will now be under extra load.

[aaron7]

Best to just keep an eye on Craigslist for someone stripping an old camper or trailer. They're usually $100-200. Make sure to have them show it working first!!