50 amp RV...only 30 amp service available...?

[StansCustoms]

We are planning a trip to a Corp of Engineers facility that only has a few 50 amp campsites...which are always full. So we will have to use a adapter to a 30 amp plug.

I know that some RVs with small gen sets have a computer controlled thermostat that prevents both A/C's from starting up at once.. because of the load spike at start up.

Our new to us Alpine is the first 50 amp RV we've had and I'm wondering if the thermostat in an Alpine has a similar power management...or any protection when both A/C's are thermostatically programmed to be on.

Will just one A/C work..or will both try to work and possibly damage them from insufficent voltage?? ...or will both work with a similar safety start up program as mentioned above...??

[Jack R]

Stan

My MoHo has a thermostat for each A/C. They only turn on if I turn them on. 30 amp isn't enough to run two A/Cs. So turn one off. I'm sure someone will be along shortly saying they run both off 30 amp just can't start both at the same time. Oh well.

jack

[pkmesser]

I have ran both AC's with 30 amp park service that was marginal in very hot weather. Just had to turn everything else off, and put refrig on propane. If it is not so hot that you really need both units, just throw the breaker on one of them. You probably have zone controls in your thermostat, if so, you can do the same thing by leaving one zone off. (Most rigs with 50 amp service do not have the compressor switching controls that were common on ones that were set up for 30 amp power. We had a MH with this capability, only one compressor would run at a time. Both fans ran all the time, that said, it did not cool as well as one with 50 amps that allow both AC's to run full out).
Just saw Jack's reply, he is right in that I don't think 30 amps will start both compressors at the same time. When I had to do the above, I allowed only one AC to start up, gave the breaker a few minutes to cool from that start, and then started the other one. It was so hot, they did not cycle.

[Jeff and Cheryl]

Stan,
The rear AC will not come on when you are plugged into 30 amp service. The Duo-Therm thermostat will not go to zone two.

[ImagineIF]

Jeff may be right, but that seems like a capability not typically found. Keep in mind that a 30A/110 to 50/110/220 adapter is taking one 30A/110 feed and bridging it across the TWO 50A/110/220 feeds you would have with 50A service. So, you are not simply reducing the current capacity to your RV from 50A to 30A, you are actually reducing the capacity fro 100A (2x50A) to 30A. Depending on your battery charger, you may be able to easily reduce its maximum load from maybe 50A to 10A.

[peliaspastia]

The posted replies are good advice. One post mentioned putting the fridge on propane, good idea, but more importantly, you should switch you water heater to propane!

[wa8yxm]

First.. You might wish to visit a web site http://www.psrv.net
I built my own, works great, usually. Alas it won't work where I'm at now but not a problem.

You need to just count 1-2 stop.. It is that easy.. What do you count? Big loads

Air Conditioners, Water Heaters, Microwaves, Space heaters. Just count to 2.

Exception.. Air conditioners.. Though I have run 2 at one time on a single 30 amp line (Total 27 amps) it's iffy, if the breaker is old or the wires are aluminum it won't work, if the concensers need cleaning (Something I will do within the next 2 weeks) it won't work.. Last time I did it I had JUST cleaned the condensers, first time I did it they were new.

But that about covers it..

And it's not a computer controled thermostat that the dual A/C 30 amp rigs have

IT's an "Energy Management System" that can shed loads, it will alternate between the two A/C's. it will shut the water heater off if you fire up the microwave,, In my rig we have to do this all by hand.

Just don't get Eva Gabor syndrom (TV show: Green Acers, Mrs Douglas (Ms. Gabore) could never understand that you could only run so much off their generator and was constantly overloading it.. Finally Mr. Douglas got the power company to give them a feed... I won't tell you how that turned out but the show said that was what they think caused the great blackout of, I think it was 1968 )

[Barbaraok]

Quote:

Originally Posted by Jeff and Cheryl Stan, The rear AC will not come on when you are plugged into 30 amp service. The Duo-Therm thermostat will not go to zone two.

Ours does. When we have 30 amp we just need to make sure that we only have one on at a time. Use the rear when we are up front, use the front when we are in back. Only when it gets near 100 do we really need 2 to keep things comfortable.

Barb

[gmfryer]

Jeff,

I have a '99 and can run both AC's on 30A. Not sure what the difference is in our units. I have upgraded to a 5 button T-stat but even before that I was able to run both on 30A. But everything else was off or on gas.

[Jeff and Cheryl]

I recently upgraded to a 5 button and have not tried both since. From multiple experiences with the 4 button, thirty amp would not power the rear air. Looks like it's time to run the experiment again. Thanks Greg for the heads up.

[StansCustoms]

Quote:

Originally Posted by Barbaraok Ours does. When we have 30 amp we just need to make sure that we only have one on at a time. Use the rear when we are up front, use the front when we are in back. Only when it gets near 100 do we really need 2 to keep things comfortable. Barb

Well shucks...looks like mine is like Barbs...the rear air will come on...then kicks out/down back and forth. I assume the front air is trying to start or something...(no noise from up front that I could hear).

However when I turn off # 1 at the thermostat the rear air functions properly. That is on my RV shed plug which is not 30 amps....more like 25. All new wiring from my shop building never the less, just for lights etc ...mostly. It ran my old rv a/c easily( one)...so I knew it should run this one....no dice on two of course, or even one when the thermostat doesn't have one in the off position.

I'll have to put in a junction box to the rear air so I can unplug it from the motor home and plug directly into a secondary power source on 100 plus days (which we have quite a few of).

Thanks for all the help...

[bjsheldon]

If the Corps campgroud has 2 -30 amp receptables at the post, get the adapter from Camping world. It makes your unit think its pluged into 50a. I yoused one for years with good sucess.

[powerboatr]

we can run both a/c on a 30 amp pedestal
i switch the fridge to gas, and the water heater to OFF and then if we need it i switch it to gas while showering or washing dishes, then back to OFF


our roof units are pretty darn miserly with amps required to run.
right now i am pulling 12 amps with one a/c on and the fridge on electric.
the a/c start the compressor then the fan comes on after the surge of 12-15

the key is not having both a/c start up at the same time
so i keep the front on 77 and the rear at 79.

once we are cooled down i leave the rear on fan and use a floor fan to move air around better as the front one cycles on and off

knowing your amperage load on your gear is key.

think about how we do power management to save flipping breakers....
we practice it at home as well

[Old Rv'er]

Stan, if the answer is not here, what kind of thermostate do you have, is their a zone button? If so, turn off one zone. Seperate therms, turn one off.