Community Forums

harleyreb · 03-10-2017, 05:28 PM

I would like to add a second ac unit to our 30A class A. The bedroom is not pre-wired. I would like to wire it so that I can run it off the main 30A coach power (I have to make sure only one ac runs at a time) or run it from a separate 20amp power cable that is plugged into the parks 20A plug. Any ideas on the wiring diagram for this? Would a transfer Switch work, or be overkill? Any way to wire this with just a simple throw of a switch to go from coach 30A power to park 20A power? Double pole, double throw, or 3 way switch?

Hope this makes some sense.

powercat_ras · 03-10-2017, 06:58 PM

One possible solution: Add another outlet in your basement compartment where your shore cable come in. Run the power from the new AC to a plug there. When trying to run both AC off your 30 A shore power plug goes to outlet. You could unplug and run 12 gauge extension cord to the pedestal when you want to try your plan B.

Perhaps your RV is like mine and there is one 20 A breaker in the box that feeds the microwave and electric side of DSI hot water heater thru a power management brain box that shuts off the DSI when the microwave draws a load. They do this so combo of AC running, microwave running, and DSI hot heater element on can't happen as this would exceed 30 Amps and trip the pedestal 30 A breaker.

All this said, there is a very good reason RV makers don't put 2 AC on 30 Amp service RV as a factory option. It will be very troublesome, you will have to be very thoughtful about what you operate at the same time to avoid 30 A breaker trips.

triplewide · 03-11-2017, 06:13 AM

Copied my post from another thread:

adding second ac
Just finished adding an 11k BTU Power Saver AC to the rear fan opening.
Amp draw, 23.5 with both ac's running and everything else off or on gas. 24.5 with both ac's and converter on. Uses about 74% of the generator's full load. Both ac's start easily and do not stall the generator.

Have not finished the final power connection yet. Have it hooked temporarily into distribution panel under bed. Have ordered 2 contactors and installed a toggle switch between the two. One contactor will supply power from the distribution panel the other from a cord in the power bay. Will allow me to get shore power for the additional ac from a 120v outlet when available and leave the 30 amp for the rest of the rv. May make an adapter so I can plug the 120 volt cord and 30 amp cord into a 50 amp outlet.

The original 15k BTU ac would pull temp down about 10 degrees below outside temp. Today, with both units running resulted in a 15 degree pull down. I think it would have managed 17 degrees if I left it running long enough. We will be happy with 15 degree pull down, 100 degrees to 85 is tolerable for us. If we are driving and running dash air, we should get 20+/- degree pull down.

Cost was about $850 for parts. Ran the wire through the ceiling using the same chase as the fan wire, through the overhead cab, down the bath wall through wire mold, through the base cab, into the bed compartment. Running the wire was the hardest part. AC install is a breeze once it is on the roof.
__________________
2015 ACE 29.3

This was from August 2016. I used 2 contactors and a toggle switch to select between shore and generator power. Works well, but a regular switch would probably work as well as the contactors as long as the AC is off when you switch it. I can send some pics if it will help you.

Glad we did it. Makes summer camping more pleasant, especially with two dogs.

Knightab · 05-17-2017, 04:13 PM

Quote:

Originally Posted by triplewide

Copied my post from another thread:

adding second ac
Just finished adding an 11k BTU Power Saver AC to the rear fan opening.
Amp draw, 23.5 with both ac's running and everything else off or on gas. 24.5 with both ac's and converter on. Uses about 74% of the generator's full load. Both ac's start easily and do not stall the generator.

Have not finished the final power connection yet. Have it hooked temporarily into distribution panel under bed. Have ordered 2 contactors and installed a toggle switch between the two. One contactor will supply power from the distribution panel the other from a cord in the power bay. Will allow me to get shore power for the additional ac from a 120v outlet when available and leave the 30 amp for the rest of the rv. May make an adapter so I can plug the 120 volt cord and 30 amp cord into a 50 amp outlet.

The original 15k BTU ac would pull temp down about 10 degrees below outside temp. Today, with both units running resulted in a 15 degree pull down. I think it would have managed 17 degrees if I left it running long enough. We will be happy with 15 degree pull down, 100 degrees to 85 is tolerable for us. If we are driving and running dash air, we should get 20+/- degree pull down.

Cost was about $850 for parts. Ran the wire through the ceiling using the same chase as the fan wire, through the overhead cab, down the bath wall through wire mold, through the base cab, into the bed compartment. Running the wire was the hardest part. AC install is a breeze once it is on the roof.
__________________
2015 ACE 29.3

This was from August 2016. I used 2 contactors and a toggle switch to select between shore and generator power. Works well, but a regular switch would probably work as well as the contactors as long as the AC is off when you switch it. I can send some pics if it will help you.

Glad we did it. Makes summer camping more pleasant, especially with two dogs.

Thanks for posting this Triple! I think I am going to do it this year. Did you use a fish to get the wires over to the wall?

rdrv831 · 05-17-2017, 09:29 PM

I want to install a second air conditioner on our 30amp class c and I am considering adding one of these to the main unit.

https://www.microair.net/products/ea...nt=30176048267

triplewide · 05-18-2017, 04:15 AM

Quote:

Originally Posted by Knightab

Thanks for posting this Triple! I think I am going to do it this year. Did you use a fish to get the wires over to the wall?

Yes, used a piece of bailing wire first then tied on the 10/2 w grnd. 14/2 or 12/2 probably would have been big enough for the 11k BTU I installed. It only requires 15 amps. Would have been easier to pull the smaller wire too. I ran the bailing wire from the ac to the overhead cabinet then pulled cable back to the ac. Least amount of wire to pull through chase that way. Running the wire was the hardest part of the install. Mousemate did a better job of concealing the wire than I did. He was able to run it down the bath wall into the night stand/ bed area by removing the left end panel from the overhead cab.

triplewide · 05-18-2017, 04:30 AM

Quote:

Originally Posted by rdrv831

I want to install a second air conditioner on our 30amp class c and I am considering adding one of these to the main unit.

https://www.microair.net/products/ea...nt=30176048267

I considered using one of these when adding the second AC to our 30 amp coach. Probably a good thing to add, but I choked on the cost. So far we have not had any issues with running the 15K BTU factory and 11k BTU Power Saver added on. Of course one day I may need to post an update when one of the compressors burns up.

Would like to hear your comments on how it works if you decide to install it. If you like it I would be more inclined to add it.

biggcrisp · 05-18-2017, 07:52 AM

I'm currently not interested in performing this mod. Though down the road I might.

My only concern would be if both units are cycling the compressors ON at the exact same time.

Maybe someone that has already performed this mod could report on real world performance during compressor off/on cycles. And what if anything happened when both compressors started at the same time?

The two separate circuit 30 & 20 amp outlets option would be a non-issue. You could also use adapters to plug your 30 amp into the 50amp plug and then use another adapter to plug your 15 amp extension cord (used only to power the second AC) into the 30 amp plug.

triplewide · 05-19-2017, 01:11 AM

Quote:

Originally Posted by biggcrisp

I'm currently not interested in performing this mod. Though down the road I might.

My only concern would be if both units are cycling the compressors ON at the exact same time.

Maybe someone that has already performed this mod could report on real world performance during compressor off/on cycles. And what if anything happened when both compressors started at the same time?

The two separate circuit 30 & 20 amp outlets option would be a non-issue. You could also use adapters to plug your 30 amp into the 50amp plug and then use another adapter to plug your 15 amp extension cord (used only to power the second AC) into the 30 amp plug.

Have used our second AC on only one 10 day trip from NC to Florida and back. Had no issues while running on generator going down and back, could have been just lucky they didn't start at same time. Used 30 amp plug and 20 amp plug at campground. Also have a pigtail that converts 50 amp to one 30 amp and one 20 amp, have not used it yet.

The soft start setup may be the answer to any hardstart issues.

biggcrisp · 05-19-2017, 04:40 AM

Agree

Thanks

Knightab · 06-21-2017, 12:05 PM

Doing this mod right now, 15k AC to be delivered tomorrow. Hardest part as was mentioned was getting the wire from the ceiling to under the bed. All gravy from there.

Knightab · 06-21-2017, 12:08 PM

Doing this mod right now, 15k AC to be delivered tomorrow. Hardest part as was mentioned was getting the wire from the ceiling to under the bed. All gravy from there. My plan is to run the new 10-2 wire to a 2 space panel box and put in a 20 amp breaker, then install another 30amp receptacle on the outside of coach to run a separate line. I bought a 50amp male to (2) 30amp female plugs rather than rely on the outlet at the panel. I bought the Brisk Air II with heat option.$758 on amazon complete with heat and control panel.

triplewide · 06-22-2017, 02:41 AM

Sounds good, let us know how it turns out!

Knightab · 06-27-2017, 08:22 AM

So the install went great! I installed the 30 amp 2 space box under the bed, ran 10gauge wire to it, connected the 12 gauge from the AC to the breaker. Drilled a 2-1/8" hole above the original 30 Amp receptacle and mounted new one and connected. To test it I used my 30 amp to 15amp pigtail and had to run an extension cord from the outlet, 25' cord. Turned on the AC on high and it works perfect, no sputter. While running on full it is pulling 13.8 amps. This is a 15K dometic Brisk air II. Finished cleaning up and ready to put her to use.