WI81YODA Posted August 23, 2010 Share Posted August 23, 2010 I have a 1981 Huntsman that doesnt have any A/C, cab or roof. I was just wondering how the roof a/c units work. Can you only run them when you're plugged into a power supply or will then run off the power from the motor like the like the interior lights will? I think most of you have a roof a/c unit, so just let me know how it's powered. Thanks. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted August 23, 2010 Share Posted August 23, 2010 The smaller roof a/c units (<9000Btuh) will need about 2000W and 120v to operate. Not really a practical proposition to get this from the engine/alternator/inverter. So, unless you install a fixed generator, you'll be limited to plugging in. The larger a/c (13000Btuh) will need closer to 3000W. Onan and Kohler generators from the factory were generally 2.5-2.8kW Quote Link to comment Share on other sites More sharing options...
John H Posted August 23, 2010 Share Posted August 23, 2010 You can add an AC to a roof vent. They are powered by 110Volts AC just like your home appliances. An inverter operating from your coach battery would drain the battery in a very short time and the inverter would operate at a HOT temperature. To check if the vent is pre wired remove the inside trim and look for three wires near the vent on the side and perhaps into the ceiling. if there are not those wires you will need to run a power line to the vent. Don't use wire smaller than 12 or 14 gauge, and be sure to get three wire cable. You could run the wire to an existing outlet or directly to the power center. A 9,000 BTU unit is fine for areas that are not HOT and HUMID and they will probably operate on a 15amp campground outlet if the extension cord is not too long. it's always better to use a 30amp plug if possible. PPL sells a 9,000 BTU unit as well as 13.500 and 15,000 BTU units. Here's a link to the Coleman low profile 9,000 BTU unit ; http://www.pplmotorh...conditioner.htm Another benefit to the 9,000 units is that they can be operated with a generator putting out as few as 1800 watts. i know because I've operated an AC with a Coleman generator. The larger units will require either a 3.000 or two 2,000 watt generators. TIP: Carry a voltage meter while camping. Check the voltage before and after turning on the AC. If it's several volts below 110 volts don't try to turn on the AC. if it dips below about 110volts after starting the AC, be concerned that that power might damage your AC. i have never encountered a low voltage with a 30 amp connection but with 15 amp plug ins about 10% of the time the voltage is questionable. Old campgrounds often have inferior plug ins. As an alternative, consider a large power fan for the vent...such as a Fantastic, Breeze Away or other brand. These can be wired to your 12 volt system. In a very humid and hot situation they probably wouldn't satisfy many campers. John H SW OH '86 21' Sunrader (with 9,000 BTU AC) Quote Link to comment Share on other sites More sharing options...
Diesel_Aggie Posted August 24, 2010 Share Posted August 24, 2010 If you are trying to be cool while you are driving you might want to check out www.ackits.com as they have an aftermarket A/C system for most of the Toyota trucks. Yours should be about $870. I have ordered several times from them for other vehicles and have no complaints. Quote Link to comment Share on other sites More sharing options...
Sandro L Posted August 25, 2010 Share Posted August 25, 2010 where do u get those numbers i looked and on specs for 9,000btu unit uses around 800-900 watts thats under wat rating in specs for ac unit. so 1500watt generator should be no problem it can be surge ratting and continuous of like 1100 atleast i suppose Quote Link to comment Share on other sites More sharing options...
Derek up North Posted August 25, 2010 Share Posted August 25, 2010 I'll admit that the numbers I posted above are ONLY based on what I've read of the experiences of others on this Forum and the Yahoo Group. I don't remember reading about anyone using smaller than a Honda EU2000 to run a small roof A/C. OTOH, I don't remember anyone saying they'd tried anything smaller and failed! I'm sure many would be delighted to discover they could operate their A/C with a 2000w inverter. Quote Link to comment Share on other sites More sharing options...
Tom W Posted August 26, 2010 Share Posted August 26, 2010 If you factor in ambient temp and altitude the generators rating goes down quite a bit. Here the altitude is 3 to 4 thousand ft one place we go it 9000ft. Quote Link to comment Share on other sites More sharing options...
Sandro L Posted April 17, 2011 Share Posted April 17, 2011 Low Profile Coleman Polar Cub RV Air Conditioner Specifications include: 1/3 hp compressor motor, the most powerful in the RV industry today Running Watts for Cooling - 1010 to 1260 Watts Approximate full load amps - cooling - 9.0 amps Evaporator Air Delivery on high speed - 200 CFM Dimensions: 44.75" L x 29.75" W x 10.63" H Weight: 92 lbs Optional 5,600 Btuh heating element to take the chill out of cool mornings. Quote Link to comment Share on other sites More sharing options...
Maineah Posted April 17, 2011 Share Posted April 17, 2011 Motor start current is about 225% of run current very short duration but it sure can make a 2,000 watt generator grunt even with a 9,000 btu unit. Quote Link to comment Share on other sites More sharing options...
Sandro L Posted April 18, 2011 Share Posted April 18, 2011 i have to find it again but have you ever heard of a hard start capacitor. it handles the high short start current Quote Link to comment Share on other sites More sharing options...
Nam Posted April 22, 2011 Share Posted April 22, 2011 Inverter won't work on AC...at least practically. The high surge will shut it down. Generator is the way or plug-in Quote Link to comment Share on other sites More sharing options...
twoblocked Posted April 25, 2011 Share Posted April 25, 2011 Supco makes various hard start capacitors which boost voltage to reduce amperage draw at startup I use a Supco SPP6E along with a 5 second "delay on start" timer on the fan motor to help my Honda EU2000i start a Carrier 13,500BTU AC on hot days. The Hard Start Capacitor: http://appliancecare...tore/SPP8E.html or eBay. The timer: http://www.primelec....l-p7845499.html The following link is a technical analysis of hard start caps and their characteristics: http://www.flickr.co...57601701602363/ i have to find it again but have you ever heard of a hard start capacitor. it handles the high short start current Quote Link to comment Share on other sites More sharing options...
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