Community Forums

Unicorn Driver · 05-20-2017, 10:00 AM

Hi all,

I have a Subaru 3500 unit at home for backup connected to a transfer switch, I just plug the generator in to a plug at the side of the house, it runs heat, kitchen fridge/freezer, chest freezer in the basement and a few other power sockets. It does not run my ac.

Let's say there was a power outage at home in 90f and I decided to bring my coach home to sleep in for air con. Would the 3500 be sufficient to run the coach air? And if so would it be much quieter setting the generator up 100 feet away from the coach. Would the 3500 be much more fuel efficient than my 5500 coach unit?

Thanks,

Stephen

Skip426 · 05-20-2017, 10:05 AM

If you have the gen set running the house fridge and freezer , there won't be enough reserve power to run the A/C in your coach . You'd have to run the coach gen set too.

Unicorn Driver · 05-20-2017, 10:08 AM

My apologies for confusion. I am talking about running the coach only from the portable unit. I would move everything out of the fridge to the MH fridge. Our chest freeze can get by with only a couple hours of power a day.

twinboat · 05-20-2017, 10:17 AM

You should be fine. 3500 watts is 29 amps and that's just under what your probably using on your 5500.

Many of them are only tapped to 1 output @ 3600 watts. The second output is only used for a second AC, if there is one.

Keep in mind that you may not be able to supply the house loads and the RV loads, off the one generator. You sleep cool as the food defrosts.

Fuel wise, if the load is about the same, the bigger engine will have an easier time making the power. So it won't use much more fuel then the smaller one working harder.

Skip426 · 05-20-2017, 10:27 AM

OK, there would still be other factors involved .
How close could you park the coach to the house gen set?
Any length of power cord results in a power drop; and low power to the coach could burn out the roof air unit.
What type of plug in; is available on the house gen set ?
If the only available plug is a 15 amp , you're in trouble.
What size is the coach A/C ?
Is the coach equipped with more than one A/C unit ?
If it has two , will one A/C keep the coach comfortable?

Unicorn Driver · 05-20-2017, 10:31 AM

The coach has two ac units but as its 30amo I can only run one on shore power. The portable genteator has a 30 amp plug on it.

I did just get a genturi for using with the on board generator. The air con units are 13500.

As the house generator is portable I can have it as close or far from the coach as my cable permits.

Unicorn Driver · 05-20-2017, 10:39 AM

Had a look at generator, it says max 14amp. So it's not going to work.

harryn · 06-06-2017, 03:08 PM

Quote:

Originally Posted by 1stMH

Had a look at generator, it says max 14amp. So it's not going to work.

Actually, the answer is yes!

The generator you have is a 240 VAC split phase, so it is providing 14 amps to each 120 VAC leg. (just like a home is actually 240 VAC split phase - two 120 vac legs to the house)

If you purchase a 240 VAC to 120 VAC transformer, the output will combine to provide the power of both legs into one each, 120 VAC output of around 25-30 amps.

If you purchase a transformer that let's you fine tune the output voltage a bit, it can be set for slightly higher at the transformer to make up for voltage drop through the long wire to your RV, at the price that some of the amps are now turned into increasing the voltage.

Transformers are widely used to make these kinds of "adjustments" all over the place.

theoldwizard · 06-06-2017, 06:26 PM

Quote:

Originally Posted by 1stMH

Let's say there was a power outage at home in 90f and I decided to bring my coach home to sleep in for air con. Would the 3500 be sufficient to run the coach air?

Yes, with proper wiring and all loads turn off inside the house.

Quote:

Originally Posted by 1stMH

And if so would it be much quieter setting the generator up 100 feet away from the coach.

A properly sized extension cord for that distance would be very expensive. Depending on how much your RV A/C draw, you will probably need a cord made out of 10/4 SJOOW (> $1/ft plus ends)

Quote:

Originally Posted by 1stMH

Would the 3500 be much more fuel efficient than my 5500 coach unit?

Yes.

twinboat · 06-06-2017, 06:47 PM

This is a old post.

The OP stated his generator has only 14 amp output, back in post #7.

Probably 3500 watts, but 240 volts. That gives him 14 amps per leg.

harryn · 06-06-2017, 09:43 PM

Quote:

Originally Posted by twinboat

This is a old post.

The OP stated his generator has only 14 amp output, back in post #7.

Probably 3500 watts, but 240 volts. That gives him 14 amps per leg.

Hi, yes it is 2 weeks old, but maybe that is not so old?

It took me 2 weeks to think of a solution and it just hit me today how to deal with it. I might have found another option for him as well but will hold back on posting it until I have checked it out some more.