Replace old Onan 5000 with box store portable

to use the 240v option, it must be "4" wire, (2) HOTS, plus neutral, plus ground

many of us have used a 3000-4000w generator with the shore cord plugged in via 30amp RV plug,
just can't run 2 A/C units at the same time

i think your biggest problem is going to be heat, IF you confine the generator to inside the oem space, plus fuel capacity, and you won't be able to use it while moving

Do you have a 30A rig and the gen supplies the main power and the second 120V circuit is for the second A/C? This was common prior to general availability of 50A.

If your store gen is 240 vs 120/240 splitting the 240 by the gen may not be practical/possible. A 240 to 120 step down transformer might work out. But a 5000W transformer will add to your cost. What is the new gen rating?

If your rig is 30A and the new gen is 120/240 capable I'd urge a lot of caution using split phase in a 30A rig.

In theory what you are saying could work depending on how your panel is wired. Box store generators produce split phase 240 VAC. If at any point in the bus bar both phases are present then you would destroy your rig's electrical system. Think bussing both out of phases together. Not a good thing. Another issue is the NEC code requiring a single NG bond in a separately derived system. Many box store generators don't have the required NG bond. Depending on your rig the NG bond could be done by the transfer switch. Without the required NG bond you could have a hot skin condition that can kill you. The last issue is duty cycle. Box store generators are rated for intermittent duty. This means no more than xx hours in every 24 hours. And they usually require full service immediately after a short run time. We have an automatic standby generator system and if it is run for 12-24 hours it requires full service, oil change, plugs filter etc. This runs up the cost significantly. Now there are more expensive stand alone generators such as Honda, Yamaha, etc. that can have a longer duty cycle. (note: they don't have the required NG bond) The Onan generators are rated for continuous duty or what is referred to as "prime power" application such as in an RV. You didn't mention where you planned on mounting the box store generator but they are not designed to be mounted in a confined compartment such as where the Onan was. That is a quick way to overheating the generator and worse carbon monoxide poisoning. Rather than attempt to modify your rig's electrical system it may be better to just plug your shore power cord into the generator until you can purchase a replacement RV generator.

Any portable generator setup that will power both your air conditioners will cost as much if not more as the repairs for your Onan and not give you the convenience of a built in generator. I would give serious thought to repairing the existing generator.

I think what you could do is replace the ATS with a 50 amp ATS. The 30 Amp, indeed all AT switches I aware of in RVs, switch both the hot and the neutral, so if you're wanting to run 240 Volt in there, with one leg providing the 30 amp, and the other leg routed to the rear A/C, you would want the 50 amp relay, and I'm sure that's possible to do the job.

ATS=Automatic Transfer Switch.

What I'd do, is pull that Onan, and go to Harbor Freight and try to find a 6500 Watt ($600) that would suit my purposes.

Most of the off brand generators are fine and last a long time when you're only using them sporadically. Usually they only need a better muffler to be as quiet as the brand names, but my research showed me that they use standard off the shelf components so that's not much of a chore. Plus you save hundreds.

They do have a gas tank on top, but most users don't mind or can come up with creative fuel adaptations.

MountainAir05 wrote:
Two 2200i Honda with the connect cable will give you 30 amp, but you are looking at Close to or over $2000. 30 amps is only one (1) 120 volt live leg. It is one 120 live leg and one ground and one neut.



The comment you stated that to separate the 240 in two 120 will not work with out jerry rigging it. A 240 Volt plug in is 120 on each slant leg and ground on the center. You 120 volt AC and anything else would not like 120v leg and another 120 volt on what is suppose to be ground.

I am in the process of helping a friend to replacing AC and other 120 volt appliance that just had the same thing done. They smoke. So far two AC, Microwave. TVs and not sure on the Charger yet . Not sure if it feed back into the engine computer and alternator. I am sure you will get other suggestions.

I think you may have misunderstood me. There are two separate input lines going to the transfer switch from the current gender. Each line contains its own hot, neutral, and ground. Both lines happen to be energized by one 120volt generator. I’m saying split the 240 and apply a 120 volt leg to each of the two inputs.

Two 2200i Honda with the connect cable will give you 30 amp, but you are looking at Close to or over $2000. 30 amps is only one (1) 120 volt live leg. It is one 120 live leg and one center ground and one neutral.



The comment you stated that to separate the 240 in two 120 will not work with out jerry rigging it. A 240 Volt plug in is 120 on each slant leg and ground on the center. You 120 volt AC and anything else would not like 120v leg and another 120 volt on what is suppose to be neutral and a Center ground.

I am in the process of helping a friend to replacing AC and other 120 volt appliance that just had the same thing done. They smoke. So far two AC, Microwave. TVs and not sure on the Charger yet . Not sure if it feed back into the engine computer and alternator. I am sure you will get other suggestions.