Dual air

[cooperhawk]

Our 345's are all wired for thirty amps and two AC's need at least 50 amps to start and run. Pat370 has rewired his for 50 amps and can now run both roof airs from shore power when he has a 50 amp hookup. When I get time I intend to do the same. Meanwhile, the only way I can run both AC's, is with the genset. I do run both AC's all the time when on the road and leave the dash air off.

[raveson]

I have to go to my 345 and get the receipt for the system I installed a couple of years ago. As I remember the cost was less then $100. and the install was not difficult. It works by seperating the circut from the generator and allows you to plug a second land power line from the gen compartment only to run the second airconditioner. I think it was from duel power systems? Will get the details and answer back later. I set a thread about this a year or so ago.

[raveson]

I have to go to my 345 and get the receipt for the system I installed a couple of years ago. As I remember the cost was less then $100. and the install was not difficult. It works by seperating the circut from the generator and allows you to plug a second land power line from the gen compartment only to run the second airconditioner. I think it was from duel power systems? Will get the details and answer back later. I set a thread about this a year or so ago.

[raveson]

Name is - Power Solutions
704-398-0996

Look at a thread dated 11-10-2006
"30A upgrade to 30A + 20A"
Drawing are in the thread.
I put the same system in and works GREAT!

[jagcb750]

I recently did this mod to my 345. Here is a pic of the knife switch that my dad (the electrician) and I installed. The trick was that we had to disconnect the wire from the selector switch above the stove where you select between microwave, front air, rear air, blender etc. We thought that if we didn't disconnect it here and we were plugged into the 20 am service through the extension chord type plug in and put the selector on rear air, then we would be sending 220-240 volts to the rear air and fry it. Now when you put the switch on rear air it does nothing. The knife switch controls whether you get power from the 20 amp plug in or from the generator. I had a time figuring out that there is a 45 second time delay before the generator or 20 amp power kicks on. Then you can turn on the rear air. Anyway, here it is.

[bkahler]

Originally Posted by jagcb750

I recently did this mod to my 345. Here is a pic of the knife switch that my dad (the electrician) and I installed. The trick was that we had to disconnect the wire from the selector switch above the stove where you select between microwave, front air, rear air, blender etc. We thought that if we didn't disconnect it here and we were plugged into the 20 am service through the extension chord type plug in and put the selector on rear air, then we would be sending 220-240 volts to the rear air and fry it. Now when you put the switch on rear air it does nothing. The knife switch controls whether you get power from the 20 amp plug in or from the generator. I had a time figuring out that there is a 45 second time delay before the generator or 20 amp power kicks on. Then you can turn on the rear air. Anyway, here it is.

JaG,

220-240 volts would not be an issue so you didn't really need to unhook the wire. I spent several evenings tracing down the wiring in our coach and made a sketch of it. Unfortunately the sketch is in our motorhome which is at the repair shop. I'll try and post it early next week when we get our motorhome back.

I did two mods while I was rewiring. The generator has a 240vac output with a neutral center tap which provides for two 120 vac circuits (circuit A and circuit B). Circuit A feeds the entire coach through the rotory switch in the kitchen. As you know that rotory switch feeds only one major appliance at a time.

Circuit B goes to the single 30 amp circuit breaker box near where you mounted your switch and it feeds through the transfer switch only the rear air. This transfer switch is active anytime the generator is running. When the generator is not running the the transfer switch is de-energized so Circuit A can feed the rear air through the rotory switch. Now, if you start the generator 45 seconds later the transfer switch is energized and Circuit B is fed to the rear A/C directlly through the transfer switch. Even if you turned the rotory switch to select the rear air the transfer switch keeps power from Circuit A from reaching the rear A/C. In no way does Circuit A come in contact with Circuit B.

In my mind Circuit B is a wasted circuit if you don't use the rear air while on generator. In my modification I installed an outlet box in the generator compartment and connected it to Circuit B from the generator. This way whenever the generator is running I have power to those outlets. Since we use our motorhome at the race track where there usually isn't any shore power available, having those outlets available means I can still run A/C in the coach (front air) and have power to run a compressor or other power tool from Circuit B. It is set up such that the outlets and the rear A/C can be energized at the same time when on generator.

The other modification was to run a second power cord from the electrical entrance compartment to the same location as the generator transfer switch. I broke the line that goes from the transfer switch to the rear air and for the time being have used a plug arrangment to isolate the rear air from the rest of the coach wiring. I'd like to find a toggle switch like you installed but haven't found one with a high enough rating that is DPDT.

Its really hard to explain and I'm hoping the sketch will clear things up

Brad

[jagcb750]

Wow! sounds really technical. I'm guessing you are an electrician then? We weren't really sure whether The selector switch set to rear air was going to provide the other 120 volts, but just wanted to be on the safe side. There is a couple of outlets on my 345 right outside the door of my coach. I haven't checked to see if they are hot when my generator is on or not yet. They are in an ideal location, however it is on the opposite side of where the generator is. Fixing up Nancy has been quite an obsession for me as of late. I've been trying to space it out so my wife doesn't think that I am spending too much time with her. She has enjoyed camping with me in her, so I assume she will allow me to keep fiddling with her. My next project is to give her a tune up.

[bkahler]

Nothing wrong with wanting to be safe . The alternative really sucks

I never checked the outside outlets with the generator running. I traced all of the generator wiring for Circuit B and I know it only feeds the rear A/C on our 310.

We're do a few repairs and a few upgrades before each trip in our 310. Eventually we'll get it all done. I hope.........

Brad

[HiHoAgRV]

My sob had the 2nd generator leg tied soley to the rear air. The 1st gen leg ran the front air and the rest of the coach. Nothing fancy, start the gen and the rear air worked. The 6.5 Onan worked fine and ran everything. To get rear air at the campground I installed a standard 110v outlet inline on Gen leg #2 and a standard 110v plug on the circuit that continued to the rear air. With the two plugged together everything worked as the manufacturer intended. At the campsite I unplugged the rear air from the gen and hooked it to a heavy duty extension cord that was plugged into the 15A campground outlet. Air in the bedroom and Momma is happy (which allows everyone else to be happy...)

[jking]

HiHoAgRV has it right! You could use a magnetric or an electronic relay instead of the manual changeover plug, but you have to prevent 'shore power' and genset power from being on the same line at the same time. The place to do this is at the 'extra' breaker box location, under the rear curbside closet on a 310. Use #12 wire, too. Be safe.
Jamie