The Stovebolt Site Forums The Shop Area The Electrical Bay Operating 110V AC in RV

I am wondering what it would take to run an 8,000BTU home type window 110v airconditioner while driving my Van ? The AC unit specs : 7.4 amps , 820 watts , Starting amps -- 22.2 , starting watts 2,442 .

I have a 750 watt / 1500 peak inverter and will not work when the compressor starts on a smaller 5,200BTU unit ( 4.8 amps , 530 watts , Starting -- 14.4 amps /1,584 watts ) . I was going to purchase a larger inverter , but wonder if inductive starting current makes it impossible to use an inverter with an AC ?

Thanks ,

Jamie Rodgers

You'd need a BIG inverter, and a heavy-duty battery and alternator to support it! Why not just install a second evaporator on the existing engine-driven AC system? I'm doing that on a motorhome I'm restoring, using a factory rear AC evaporator out of a conversion van somebody gave me to get it out of their back yard. It's a little work, but all the parts are useable, with a little tinkering.
Jerry

HI Jerry ,
I'm just tired of struggling with automotive AC , compressors , hoses , expensive freon , etc. Apparently current draw is minimal with the 8,000BTU AC once the compressor has started . I have this neat little unit in the back window of full size van and just wondered if was even possible to use it with an inverter ? With the remote control and high effeciency of the new units , it would really be nice and , if something went out , one could simply replace the entire unit for $150.00 .
I sent an e-mail to an inverter mfg. and hope to hear back . May be impossible because of the inductive thing ( whatever that is )? I'll post any information I receive .

Thanks for the response Jerry ,

Jamie

I can sympathize with you on the Freon issue, but converting to R-134 isn't difficult, and it's available over the counter in most places. (At least here in Tennessee). You might consider installing a "hard start" capacitor on the 110V unit if you're determined to go that way. Most refrigeration supply shops could advise you on that project.
Jerry

HI again Jerry ,
I had hoped to hear from the Inverter folks , but have heard nothing today . My comprssor is out on the van and just decided to pursue the possible use of the 110V system . My brother has a friend who makes special alternators for emergency vehicles and some are 700 amps . He also makes inverters so am awaiting word from him also . I do think a standard alternator will work fine once the compressor is running .
A starting capacitor is possibly an option , but not sure if that is possible on this small sealed type compressor ???? I'll keep you posted and thanks Jerry ,

Jamie

Practically all compressors are capacitor-start, they mount outside the sealed unit. A "hard-start" kit just adda a little more capacity. Most any good HVAC shop could probably fit one to the window unit. Good luck! BTW, I've used those little window units to add to the cooling on an old motorhome, just ran the auxiliary generator while I was driving!
Jerry

Jamie, An inverter draws roughly ten precent of it's wattage rating in amps and that's whether you are using it or not. From here on my knowledge get's a little shaky and depends on your equipment. Most motors draw their peak amps at start up. Are those spec.s for the AC running or startup. You'll need to know what that is for your AC unit to calculate inverter size, and then find an alternator to supply the amps. Sounds like you have a source so you may be half way there. I'm not sure what stress you'll put on the inverter starting the AC. I think Jerry's right run an auxillary generator.

Larry
68 C20 327 daily driver
63 C20 292 Camper truck
65 C10 ? Custom Cab AC,PB,PS,$flasher - Long term Project

Hi Larry ,

The 8,000BTU AC shows 7.4 AMPS and 820 WATTS . That should be running . According to GE , start up takes approx. 3 times the running amps so should draw 22.2 amps ( 2,442 watts ) at start . I have not heard from anyone who makes inverters yet . I contacted Coleman and Vector .
It seems that some devices have some sort of inductive current requirement that can't be met with an inverter ?? I am very unclear about that . Makes me think an inverter does not deliver pure 110 V electricity as we know it ??
I have a small RV with a power plant and the roof air works fine on that generator or plugged , of course . My van is just a full size van . Works great plugged in so I am going to go as far as I can on this . I see an inverter in a catalog rated at 2,000 watts continuous and 4,500 watt surge . It is $329.99 and would pay that if it would do the job ??? I'll let you know what I find out . Maybe we can all learn someting from this endeavor ???

Thanks Larry ,

Jamie

We had a customer try this on a van converted to a camper, he bought the biggest inverter he could find, we installed several dozer batteries in the back, he spent well over $1000-& he could use the unit for maybe an hour. If the technology was there we would be driving electric cars already. Brian

HI Brian ,
I think the difference in his project and mine is that my unit is small and I do not want to try to run it strictly on batteries , I just want to use it while driving and then can hook up to 110v when in an RV park . It still may not be practical , but should learn something soon from the fellow who makes alternators and inverters for the emergency vehicles .

Thanks Brian ,

Jamie

This sounds like an incredibly complicated solution to a nonexistent problem. You've got a couple of hundred horsepower available to run a compressor off the crankshaft, and plenty of technology already in existence to get that van as cold as you can stand. Just get a regular automotive AC system working, and drive on! I've been installing and/or repairing automotive systems since 1959, and they're not that complicated. Adding a second evaporator back in the van is simply a matter of running a couple of hoses down the frame, and mounting the evaporator with the necessary fan speed and temperature controls. Charge it up with R-134, and chill out!
Jerry

Hi Jerry ,
You and I both know that you are absolutely right and I would imagine that is what I'll eventually do . I just got to fiddling with inverters for TV , VCR , etc. and thought this might not be terribly complicated . Inverters have come down in price and Window AC units are far less energy demanding than they usd to be , cheap and the remote control feature seemed to make it a feasible quest . Seemed a shame to be driving along with a perfectly good AC in the back window that I could not use until parked . I am still curious and anxious to hear from the fellow who makes the alternators and inverters for ambulances , etc.

Thanks for the response Jerry . I will let all of you know what I find out from the alternator developer . I doubt that I would go to the extent of installing a 700 AMP alternator . Just a larger Inverter would not have been a big problem .

Jamie

A few years ago I bought a Van at a Cable company auction for $200, not cause I was really interested in the van but because it had an AC Generator mounted in the back. This unit is about the size of an old tubular style vacuume cleaner and sits behind the seat. it also has a secondary battery with it there and heavy (Jumper cable looking)lines that run up to a heavy duty alternator with a dual battery charging circuit hooked up to it, it only functions when the van is running but I've been able to power lots of stuff off it, specifically all manner of power tools including a table saw, my furnace in my house and some lights 2 years ago when an Ice storm killed my power for 8 days and a small GE air conditioner I bought from Wally-Mart for my travel trailer. (Prob. the same one you have Little white remote $150). Since then I've decided to sell the van and remove the system and build it into a toolbox that I could plug into my truck whenever I need it to power whatever, Including that AC unit in my travel trailer so I can cool it down before we get to a campsite for summer travel, been meaning to try the little microwave in the trailer with it too be nice to have that highway popcorn.
From the looks of it the generator is just a big DC motor tied to a generator head.
Might look around for places that do conversions for utility companies maybe they'll give you a deal, I have no idea what they cost new.
MONGO

Hey Mongo ,
That is super interesting . Does it require an unusually large alternator to keep it from draining the battery while driving ?
It sounds as though that would be ideal if the Inverter idea just won't work . I'll start looking for AC Generators .

Thanks ,

Jamie

Given that your AC requires 900 watts to run and the invertor would have about 100 watts loss while running you would need an alternator capable of providing 1000 watts (84 ampps at 12 volts) just to keep the AC operating. To operate from batteries for more than a few minutes you would need a battery bank weighing more than the vehicle. And this is without running any other accesories in the vehicle or operating the vehicle itself!

Hi Joe ,
You just provided some valuable information and I thank you . I have wondered how large an alternator I would need . I actually have a 100 amp alternator and do not intend to try to run the AC without the vehicle running . I also carry a standby starting battery .
Did It say that you are in Canada ? If so , and you would care to correspond , I went to school in Edmonton Alberta in the 2nd. grade . Feel free to e-mail me at [email protected] . I welcome anybody who would like to e-mail . I hate to clutter this nice forum .

Thanks ,

Jamie

Hi crew ,

I have just ordered a 2000 watt continuous / 4000 watt surge Coleman Inverter . Have gotten no response from Coleman or Vector to date and nothing from the fellow who builds high output alternators . Guess I am just going to have to experiment . If nothing else , this inverter should easily run a 1,500 watt electric heater that I have in the back of the van .

Probably should discontinue this Post session to clear some room for others . I'll Post again if I have any success .

Thank all ,

Jamie