Forum Discussion

Buster52's avatar
Buster52
Explorer
Aug 03, 2014

Running both A/Cs

I just bought a 1989 Southwind. The generator needed some work (both the control and voltage regulator needed replacing) so I was using the A/Cs to put a load on the it. It is a 6.5kw Onan and should have plenty of power. But as soon as I try to use the second A/C the gen dies. It will work on ether A/C but not both. There is no other load on the system. There is a selection box that will not allow more then one to run at a time when on shore power. Is there something I am missing? 6.5kw should be enough power or wouldn't have a 4kw generator.
  • my 87 pace arrow would only handle 1 at a time. if you wanted to run the second and had a 20 amp socket at the pedestal u could use an extension cord to 2nd air plug. nature of the beast.
  • A 5k Onan will run 2 AC units. Your 6.5 is MORE than capable of running 2 AC units. Since the 2nd load kills the APU, try running the 2nd AC FIRST and then start the 1st unit. IF the APU still dies, your APU carb/Governor system is not set up correctly. OR your APU is NOT running at the specified 1800 RPM's. The Governor keeps the APU AT 1800 when loads are applied. When you apply a load, the Governor "pulls" the throttle slightly to keep the APU at 1800 RPM's, and constantly adjusts depending on the load. The odds are the Carb is gummed up. Doug
  • My 1993 6500 watt generator will run both my A/C. In order to run them it has a 30 and a 20 amp section.
  • I would first make sure that the generator is getting enough gas. You might have a problem with the fuel lines or fuel pump. Try running the fuel pump into a gas can to make sure that there is no crud in the line. Swap it out with a new one and see what happens. (You should always keep a new one on hand anyway.) Try running it out of a gas can. Check the air filter and air intake.

    Then try a different load as was suggested. Add together some electric heaters. You may have a problem with one or both of the AC's. Good luck with your repairs.

    Miles
  • Hi,

    Keep running new gas through that generator. Eventually you will get out all of the varnish, and it should start to run better. You can take off the air filter, and try spraying in some carb cleaner while it is running and under load.

    You can also try increasing the load on the generator by running one A/C (1400 watts) and a electric heater. You can start it on low - 800 watts, then change to high - 1500 watts. If it will run both, try shutting off the heater at the same instant as the second A/C starts, even though it will add a surge start load (about 2,500 watts at start up) it will be shedding a 1500 watt heater load so the throttle should be nearly full open when the A/C starts.

    Good luck!

    Fred.
  • I guess my '02 Fleetwood Southwind has a better power management system.
    It will run both air conditioners on either 30 amp shore power or the generator.
    IIRC, the generator is a 5.5 Onan.
    The coach is not wired for 50 amp service.
  • Is the generator still a 30 amp or 500? If it is designed only to run one or the other on shore power then the generator should do that same thing. A coach that is from the 80's was really the time when the idea of 2 generators was starting to be used and the issue of running both of them at the same time was new also. Most RV parks were 30 amps at most and it wasn't until the mid 90's that RV parks started turning to 50 amps. The main reason was so people and RV manufactures could use 2 ac's at the same time. One way is to have the one ac run on the ac circuit and the other one runs on a 15 or 20 amp wall plug. Bottom line is that your source for running both at the same time HAS to be 50A