Running Ac with small generator

Tesoro · 07-03-2016, 07:43 AM

Hi. I just bought a 2013 21rbswe. Am rigging it up for our needs. So far like the camper alot. Seems to be well put together - lots of fasteners, wiring is done correctly etc. I took out the dinette in the slide and let me tell you there was no cutting back on screws and wire nails in the making of the frame! plus I havent found piles of sawdust and improperly crimped wiring connectors like I did in my 2013 arctic fox. cabinetry is above par as is fit and finish. I bought an older version with little to no use vs a newer one because I dont like the frameless windows plus the 2103 was depreciated out.

anyhow... I try to keep it simple stupid for camping so I have a 2000 honda gen which is fine to charge batteries and supply 110v if I need it. The only thing it wont run is the a/c - well it should run it on low but it cant start it. The a/c draws 1400-1600 amps (lo/hi) when operating. This means it prob needs about 3500 watts to crank it up. I had a 5 ton a/c in an previous house and a 6500w diesel backup genset. Of course the genset wouldnt start a 5 ton but I made it work. What I did was have my electrician install an large aftermarket capacitor to provide the extra momentary amperage needed to start up the compressor motor. So am thinking of doing this on a smaller scale. Anyone read or heard of anyone trying this on coleman mack a/c???

Festus2 · 07-03-2016, 08:09 AM

Some folks have tried adding a hard-start capacitor to the A/C when using a 2000W generator with mixed success. Don't forget that the generator, while rated at 2000W, only has a maximum operating wattage of around 1800W.

Also, if you do somehow manage to get the A/C to start and run, there are other current draws to consider such as the H/W tank, fridge (on a/c), converter, etc., that will eat into the generator's output. In addition to these "constant" draws, you have to consider any appliances that you might want to run at the same time such as your coffee pot, microwave, etc. Using your microwave at the same time as your A/C with the 2000w generator just won't work. You could be spending a lot of time running about resetting breakers (lol)

There is a very real danger of the A/C circuits malfunctioning and suffering damage because of inadequate output from the generator.

If running an A/C is a necessity, I think you'd be better off investing in a larger generator with the capacity to not only start your a/c but also run it without fear of damage to it but also have the capacity to run and operate other items (appliances, for example) at the same time.

I'd be looking at 3000-3500 watt capability as a start.

Tesoro · 07-04-2016, 07:05 AM

Thx for reply. I really only wanted to be able to use ac for occasional afternoon when it gets hot in the mountains....to cool down the trailer and then turn off for a while. I hadnt thought of the fridge and and unfortunately it only has auto mode and not ability to choose to run on gas when hooked up so shore/gen
I guess I could just turn off the fridge and not run anything else. Whole idea is to keep it simple and not pack a larger genset or dual 2000's. I pulled off shroud and got the amp numbers off my ac and emailed em to a company that sells hard start capacitors to see what they say. Also have to keep in mind that the 1/3 hp fan motor also draws some juice not alot but like you said the max continuous on the little 2000 is less - actually 16 amps.
You are right in that it probably wont work without eventually damaging the a/c due to lower voltage. I am also thinking about the fact that can only plug genset into the 30ft or however long it is shore power cord. Thats alot of wire and it will suck down some amps also.

Festus2 · 07-04-2016, 07:21 AM

Quote:

Originally Posted by Tesoro

Thx for reply. I really only wanted to be able to use ac for occasional afternoon when it gets hot in the mountains....to cool down the trailer and then turn off for a while. I hadnt thought of the fridge and and unfortunately it only has auto mode and not ability to choose to run on gas when hooked up so shore/gen
.

Tesoro -
If your fridge is Dometic doesn't it also have a "manual" setting enabling you to choose the mode you want - either gas or electric? On our Dometic fridge, I can select Auto, Gas or Electric. Setting it on GAS allows me to run the fridge on propane and use the generator to supply 110VAC.

**chuckster57** · 07-04-2016, 07:39 AM

If your fridge only has auto mode, simply take the bottom cover off outside and unplug the 110 cord. the control board will force it into LP mode. New Norcold only have auto mode and I have to do this during PDI to assure the LP side works. The 110 is used for the heating element not any controls.

Tesoro · 07-04-2016, 07:43 AM

oops yes it does! Had to read the manual as just bought this thing. What confused me was if you push it on and then auto the on light stays on when on shore power. If you push the gas button the on button turns off.

Desert185 · 07-04-2016, 09:03 AM

Get a second Honda and run it in parallel. Problem solved. My single 2K gen will run the Keurig with the fridge in gas mode and microwave by itself, but anything more or in combination, I fire up the second gen.

Tesoro · 07-05-2016, 06:05 AM

even with the obvious advantage of having a second backup genset and added juice when needed, I would like to try to make it happen with just one. I dont intentionally camp where it so hot need ac and if that occurs for more than a few days i'll pack up and head for the coast or a shady rv park with shore power!
I am trying KISS on this camper setup.

One other thing to do on running the ac with lo power genset is to put a time delay on the fan motor of 5-10 seconds. I had forgotten that I had done that on my last house a/c successful experiment.

Festus2 · 07-05-2016, 08:27 AM

Don't take this the wrong way but it appears to me that, in your efforts to "keep things simple" in your camper, you are actually making things more complicated by embarking on a couple of modifications to your A/C system to make it work with only a single 2000W generator. The changes that you have considered are to the fan and the capacitor start-up system.

Even after making these alterations, there remains the distinct possibility that your A/C could suffer damage as a result of trying to operate it with low power.
As I mentioned in a previous post, even if you do manage to get it running, there will be "no juice" left for any of the remaining items that require "feeding" to operate. In addition, you have no guarantee that the changes you are contemplating will be successful.

To my way of thinking, the simplest thing (but not the cheapest) you can do is to go out and get yourself another generator. Having two will solve your problem and, at the same time, give you much more flexibility. Other than the additional cost, it doesn't appear to be as complicated as the modifications you are considering.

Or, as you suggested yourself, if it gets too hot and uncomfortable, move to another cooler location or to a place with hookups.

dcg9381 · 07-05-2016, 09:29 AM

Quote:

Originally Posted by Tesoro

I really only wanted to be able to use ac for occasional afternoon when it gets hot in the mountains....to cool down the trailer and then turn off for a while.

Another thing to note here is that generators make less power in the mountains. They also make less power when it's hot. The combination of both is called "density altitude" and can impact naturally aspirated motors.

2000 watts is probably already at the limit of what could be used to start up a well-isolated AC unit. Doing it in the mountains when hot, it may decrease the performance of that generator...

Tesoro · 07-06-2016, 09:17 AM

You guys are 100 percent correct in your recommendations. I really just wanted to do it for the sake of doing it. Plus I am assuming that these rv ac's have some pretty good built in protection from crappy ac shore power as its prevalent in rv parks. HOWEVER I hadn't factored in the altitude effect! I camp at 5000-6500 ft so there is no way a 2000 will pump out enough amps that high. Thanks for the reminder! I don't really want to buy n pack around a second gen for the occasional use so I'll just find a cool spot in the event of heat wave! Appreciate the valuable input and I think I will concentrate on upgrading my converter and building a rack to handle 4x6v batteries.

nellie1289 · 07-06-2016, 12:13 PM

Quote:

Originally Posted by Tesoro

You guys are 100 percent correct in your recommendations. I really just wanted to do it for the sake of doing it. Plus I am assuming that these rv ac's have some pretty good built in protection from crappy ac shore power as its prevalent in rv parks. HOWEVER I hadn't factored in the altitude effect! I camp at 5000-6500 ft so there is no way a 2000 will pump out enough amps that high. Thanks for the reminder! I don't really want to buy n pack around a second gen for the occasional use so I'll just find a cool spot in the event of heat wave! Appreciate the valuable input and I think I will concentrate on upgrading my converter and building a rack to handle 4x6v batteries.

Grants pass? good luck finding a cool spot even at elevation. One thing I would recommend is look into the champion 2800/3100. its a great little generator and easily runs a 15k btu a/c and everything else in your trailer. I own it, it is whisper queit. I also own a Honda eu 2000 for tailgaiting but am thinking about selling it as the champion is so great. Costco usually has them online for 699$(gas only) and are currently out as it is selling like hot cakes, but here is a link to one on amazon(the Costco one is all black):

https://www.amazon.com/Champion-Powe...rter+generator

Costco has this dual version right now(which I have seen on coupon as low as $849). you could sell your Honda on craigs list for probably 750 and have all the power you ever need.

http://www.costco.com/Champion-DUAL-...100284958.html

I will tell you I have a Yamaha 4500ise mack daddy generator that was 3,000$ and this champion will run right with it and just as quiet and economical!

Tesoro · 07-07-2016, 07:36 AM

Ha I just drive 2 hrs to the east and up at 5000 ft lake! one more hour am camping on a 6500ft lake!

The storage hatch in my cougar dosent have a tall opening. I have to put in the 47lb honda sideways and then I can stand it up. Cant do that with a 97lb champion.

I have had such good luck with all honda gensets over the years that be hard to switch to a chinese made version. One time I ran my honda 1800 for 1 1/2 months for 8 hrs a day after a hurricane in 1998. Once we got power back I put it in the shed and forgot about it for 2 years as I had bought a larger version for the next 'event'. I gave the 1800 to a friend and we pulled it out and took carb apart, cleaned it and washed out the tank. It fired up on the 3rd pull! It is now 2016 and that honda still runs fine when he uses it for occasional power outages. That says something about the quality of the the electical side of the honda, esp considering we were in corrosive ocean environment.

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