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Squid 05-20-2016 01:04 AM

110 volts and AC
 
In the past on my trailer pulls I was always told never run the AC on the house 110 volts. Was going thru Eds AXIS user guide and manual and the impression I got was it was ok. I always thought it would burn up the compressor because you needed 30 amp...
Thoughts?

JamieGeek 05-20-2016 01:27 AM

I run our Axis' A/C all the time on our house 15A plugs.

The biggest issue is startup current. When the compressor kicks on is when it draws the most current. In my case if the circuit I have it plugged into has anything else running I'll trip the breaker. If I keep everything off that circuit it has no problems.

I also used to run our 5th wheel's A/C on the same 15A plug. Had that guy over 10 years and never had an A/C issue with it (also ran the A/C on the two other campers we had before that on the same plug).

I don't see how you can burn up the compressor--unless there are some problems if the compressor suddenly shuts off right during startup (which is what happens when the breaker trips at max current) but, again, I've never had a problem.

axis earl 05-20-2016 02:01 AM

Quote:

Originally Posted by Squid (Post 34956)
In the past on my trailer pulls I was always told never run the AC on the house 110 volts. Was going thru Eds AXIS user guide and manual and the impression I got was it was ok. I always thought it would burn up the compressor because you needed 30 amp...
Thoughts?

No.... I haven't had any problems running it on the house 15 amp circuit. Kind of interesting though, when I plug in the 30 amp surge protector I bought.... it always trips the circuit breaker on the house.

Chance 05-20-2016 04:44 AM

Quote:

Originally Posted by Squid (Post 34956)
In the past on my trailer pulls I was always told never run the AC on the house 110 volts. Was going thru Eds AXIS user guide and manual and the impression I got was it was ok. I always thought it would burn up the compressor because you needed 30 amp...
Thoughts?

If your AC needed 30 Amps to run, then all motorhomes with 30-Amp service would not be able to run anything else when AC was running, right? And clearly that's not the case.

A 15-Amp circuit is cutting it close under some conditions, which is why I prefer plugging into a 20-Amp circuit when available. For example, a 15,000 BTU/hour AC which is not high efficiency can pull close to 15 Amps on a hot day, particularly when RV is also warm inside. On the other hand a high-efficiency 13,500 BTU/hr AC should pull well below 15-Amps.

What you never want to do in my opinion is use a long extension cord that is not rated for the high current an AC will pull. This will result in voltage drop in extension cord, which means voltage at AC will be lower. And the lower voltage at AC means it will pull more current, which then causes more voltage drop in extension cord, etc. If a breaker doesn't trip first you may very well damage an AC compressor under these conditions.

When practical, I use the 30-Amp RV extension cord and then use an adaptor right at the receptacle. This way I minimize chance of overheating motor due to low voltage.

Squid 05-20-2016 03:01 PM

Thanks all for the input... Chance, I think you nailed it. I was going to just use a regular extension chord but not now! I have plenty of 30 amp chord to reach the juice...
Thanks again and happy camping! Heading to Medina Tx today.

Chance 05-20-2016 04:13 PM

Quote:

Originally Posted by Squid (Post 35016)
...cut...

Thanks again and happy camping! Heading to Medina Tx today.

I'm envious. If not familiar with The Apple Store (I think that's what it's called), check it out. It's on Hwy 16, and has great apple pies. Behind the store you can get a burger or sandwich also. They supposedly use like 5 pounds of apples per pie. Turnovers aren't bad either. This was one of my favorite lunch places in the middle of a century bike ride -- a great place to get some extra calories. Unfortunately I haven't been there in the last five years or so. Hope it's still good.

bevedfelker 05-20-2016 04:37 PM

Just remember, you're not going to be able to run a lot of other stuff when you are plugged into the house 15 Amp circuit. Remember you are always running the MH's converter when you have the shore power connected and on.

Don't try to run the refrig on electric, the hot water heater on electric, a TV or two, or other items plugged into the AC wall plugs. When you are running the A/C and the converter you are just about at the top end of the AC demand curve.

JamieGeek 05-20-2016 04:49 PM

Just to wrap up on my input:
Yeah I never use a 15A extension chord to plug in the RV. Always use the RV's 30A one with the small 15A converter right at the end.

I happened to be looking at our build list for our RV earlier and noticed that we have the smaller A/C unit. Your results may vary if you have the 15k unit instead of the 13.5k one.

Chance 05-20-2016 06:59 PM

1 Attachment(s)
Quote:

Originally Posted by JamieGeek (Post 35025)
Just to wrap up on my input:
Yeah I never use a 15A extension chord to plug in the RV. Always use the RV's 30A one with the small 15A converter right at the end.

I happened to be looking at our build list for our RV earlier and noticed that we have the smaller A/C unit. Your results may vary if you have the 15k unit instead of the 13.5k one.

I agree it's good to check. That's why I make it a point to mention that not all air conditioners are the same; not even when they are the same size. Operating conditions also affect actual power requirements, so that too should be considered.

I'm not sure what brand or model air conditioners Thor installs, but it's likely not the more expensive high-efficiency units, at least not on lower-cost motorhomes.

Attached we can see that even a 13.5k air conditioner can pull over 15 Amps, and when running under warmer conditions and lower voltage, current goes up considerably from there. It starts at 15.3 Amps and could approach 20 Amps under severe service conditions (warmer and lower voltage).

A 15k air conditioner that is not high efficiency could trip a 15-Amp breaker on a warm day easily. It pays to check details.

It'd be nice to be able to order high-efficiency air conditioners as options if not already included.


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