amps required to run Dometic A/C

[Barry Parkof]

I know this question has been asked and answered before, but can I run my Dometic Penguin A/C (13500 btu) on a standard 15 amp circuit. I am thinking that I can turn the fridge to propane, and turn off the battery charger during the hot hours.
We are traveling and will be visiting freinds, and our two little dogs will need to stay inside, but that is not possible without A/C.
Thanks,
Barry

[Dan@LED4RV]

Barry,
It is not advisable but some people do it. You will notice the end of your shore cord will be getting warm. It is also hard on the AC fan motor.
I strongly worn that if you go off and leave your dogs there and the breaker trips with no cool air it could be very bad for your little ones.

Dan

[HowieE]

A 15 amp circuit is wire with #14 wire that is rated at, Yes 15 amp but the breaker should trip at about 12 amps. This is to protect the wiring.

If the AC starts and the breaker holds for any length of time you will most likely have a fire in the house wiring as the wiring will heat up.

Another consideration when pulling 15 plus amps through a wire not rated for it will be a drop the voltage. Depending on the length of wire from the panel to the AC you could drop the voltage enough to kill the compressor in the AC. the compressor will be damage at voltages below 105 volts. Over heating.

In other words you are not only operating outside the code but it is just a dumb idea unless the insurance is paid on the house.

[HiHoAgRV]

Originally Posted by Barry Parkof

I know this question has been asked and answered before, but can I run my Dometic Penguin A/C (13500 btu) on a standard 15 amp circuit. ...
Thanks,
Barry

It's going to depend on the actual model of the AC unit...
According to the specs from Dometic, the fan typically pulls 3 amps...
Some models of the 13.5 K BTU compressor pull as low as 10.3 amps...model 520315.501 for instance
If a 15 A plug won't handle 13.3 amps sumthin' is goofy...

BTW...I run my 11 K BTU AC off of a 15 amp cord...it pulls 12.6 amps

Ya gotta pay attention and make sure the cord/plug don't get hot but ya also need to do that to the 30A stuff when you are really crankin on it...

[richinny]

are you going to use an extension cord?

[Inland RV Center, In]

Originally Posted by Barry Parkof

I know this question has been asked and answered before, but can I run my Dometic Penguin A/C (13500 btu) on a standard 15 amp circuit. I am thinking that I can turn the fridge to propane, and turn off the battery charger during the hot hours.
We are traveling and will be visiting freinds, and our two little dogs will need to stay inside, but that is not possible without A/C.
Thanks,
Barry

There is no "exact" current draw.

The sted current draw, is for a standard day ambient temperature.

However, the hotter the ambient temperature, the higher the currect drain.

As an example, on a "very hot" day, 105 to 110 degrees, that currect draw can get to almost 18 amps.

An extension cord is ok, but even for a short distance of 25 to 50 feet, the wire size should be about #6 awg.

Andy

[Barry Parkof]

I am not sure if I will need an extension cord, but if I do, I have a 12 gauge 50' extension. It's interesting, but it seems that the line that feeds the unit in the roof is about 14 gauge. I might be close enough to use my 30 amp cord with an adapter. I always check the lines for heat, as well as using a analog voltmeter. I can't seem to locate the instructions for this the unit, but the Airstream manual states not to run it below 105 volts.
I will not be leaving the immediate area, and will be checking on the dogs periodically (every 15 minutes). Probably will just leave the windows open with the fantastic fan on.
At this point, I am just curious.
I also am not sure if it's the 13500 btu. The stream is a 2007 25' FB.
Thanks,
Barry

[lewster]

The A/C might only pull 13.2 amps, but there are other electrical draws when plugged into shore power, like the converter, fridge on AC, etc.

The best way to determine if you are OK on a 15 or 20 amp circuit is to do an actual amp draw measurement with an AC amp clamp. IIRC, Sears has a little gizmo that plugs into the outlet and allows you to put an amp clamp around the hot leg, which is run thru it's own channel.

Or you could get a Kill-A Watt and plug it in. They are generally pretty accurate.

[richinny]

it is a long thread but should answer many of the factors involved. ask again if you have more questions :-)

http://www.airforums.com/forums/f37/...age-51758.html

[Barry Parkof]

Excellent thread. Thanks. I will be using fans and hoping it is not too hot.
Barry

[ROBERTSUNRUS]

Originally Posted by lewster

Or you could get a Kill-A Watt and plug it in. They are generally pretty accurate.

Hi, Lewster. I was trying to test my system by running my Yamaha 2400 generator, Kill-A-Watt, and 11,000 BTU air conditioner. The Kill-A-Watt could not hold that large a load and was flashing. I disconnected it. My generator or 20 Amp house outlet runs my A/C just fine. I think the air conditioner and converter was too much for it. [Kill-A-Watt] Note: I think the Kill-A-Watt has some sort of built in safety, it was not damaged and I still use it in my trailer.

[Barry Parkof]

On another note, which I am sure was discussed at an earlier time. Where would I be able to install one of those very quite & lightweigh Onans, or even the Honda generators? What about repositioning the batterys from behind the propane bottles.

[bryanl]

The confusion here is about what 15 amp circuit you are going to plug into. A standard 15 amp household circuit should have no problems with the RV A/C if that is the only thing on the circuit, the connections are good, and you aren't using extension cords.

Gensets sometimes have problems because they can't handle the compressor startup surge.

Standard RV power cords are 10 gauge for 30 amps at 30 feet. 6 gauge is only used for 50 amp RV service. See American Wire Gauge table and AWG Electrical Current Load Limits to figure out voltage drops. A 50' 12g extension will loose a bit under 3 volts at 15 amps. This will be OK if the supply voltage is above 115v. (if the circuit had 14g wire typical for 15 amp household circuits and you were 100' from the breaker panel, you'd loose near 8 volts. That'd be OK if the panel supply was 120v or better) -- the lesson is that the talk about wire gauge and so on isn't worth much unless the supply voltage is suffering and then the problem is really with the supply. A/C voltmeters can be found for $20 or so and are a good way to keep track of whether you are getting a proper supply to your RV (always more than 110v).

An autoformer will help assure against voltage drops but I am not so sure it'd be a good idea on a 'just fit' circuit such as this case. They can also provide protections from brownouts and some other problems so maybe.

A problem besides potential power faults is the fact that an RV does not have much thermal mass and an A/C can typically only provide 20 degrees of cooling. This puts time constraints on how long you can leave the dogs safely without checking. See how long by cooling the A/C on a hot afternoon and seeing how long it takes to warm in the sun.

Of course, you will want to have water available, sun protection (foil bubble foil insulation in the windows can help a lot), and perhaps a 12v fan to help circulate air. An RV is better insulated than a car and dogs can deal with warm if they have a cool spot to get to and water available.

Also keep in mind that there are those who see an animal in a vehicle, assume the worst, and call animal control to break in and save the animals from the heat. You might post a cell phone number on the door to call you if there are any concerns about the animals, maybe.

The Kill-a-Watt is a great way to check voltage and power draw (only $25, too). My guess is that it had problems with the initial surge or the power factor of the A/C. You could still use it to see the voltage inside with the A/C running.

[Barry Parkof]

A/C questions.

Originally Posted by Barry Parkof

On another note, which I am sure was discussed at an earlier time. Where would I be able to install one of those very quite & lightweigh Onans, or even the Honda generators? What about repositioning the batterys from behind the propane bottles.

[richinny]

http://www.airforums.com/forums/f448...tor-54172.html

http://www.airforums.com/forums/f448...gue-47939.html

http://www.airforums.com/forums/f48/...ting-4889.html

http://www.airforums.com/forums/f395...eam-55964.html

[ROBERTSUNRUS]

Originally Posted by bryanl

The Kill-a-Watt is a great way to check voltage and power draw (only $25, too). My guess is that it had problems with the initial surge or the power factor of the A/C. You could still use it to see the voltage inside with the A/C running.

Hi, that is what I do now; I watch my Kill-A-Watt, inside of my trailer, to monitor voltage.

[lewster]

Just a quick note.

All RV air conditioner/heat pumps are rated to drop the air temperature from the evaporator into the coach at 20* below the AMBIENT air (actually 18*-22*) measured at the RETURN for that unit.

As the A/C works, it continually cools the inside ambient air and the temps continue to drop until the thermostat is satisfied.

[bryanl]

Gensets can be interesting. I have an Onan 2800 watt microlite which runs an 13k BTU A/C even at altitude along with accessories. But then I have had a Onan 3000i fault on the same A/C but only when used with 50' of ten gauge extension cord.

The problems appear to be the initial compressor surge which can be several times the steady load, the power factor, and altitude.

The double Honda 2000i setup has worked well for keeping the A/C going on hot afternoons. The 3000i is iffy. Reports I have heard about the Yamaha 2400 are mixed. A Boliy 3k seems to have done well on this test at Unionville recently.

What I see is that 3kw genset capability is marginal and 4kw is needed for reliable service. The mechanical gensets like the Onans have mechanical mass to help with the initial surge while the inverter types may or may not have needed surge capabilities.

Batteries need a proper vented battery box, even AGM's (although many sidestep code with these). Repositioning them runs into many interesting problems. As you can see from Ricky's links, a lot of creative energy has gone in to adding gensets to trailers. (I've got an Overlander with a genset compartment mod but fuel supply and battery leads were obvious problems to the installer).

re: "As the A/C works, it continually cools the inside ambient air and the temps continue to drop until the thermostat is satisfied. " -- but they only have so much capability and when heat gain through walls and windows matches A/C capability, the temperature will drop no further. If your RV A/C can hold 20 degrees colder inside than outside on a hot day, it is doing pretty good relative to the experience of most of those of my acquaintance.

[rodsterinfl]

Found this older thread and thought to add a comparison. I have a 11K Dometic that draws 12.6 amps. Ironically I have a vacuum sweeper that pulls 14 amps. I have noticed that the vacuum cord gets warm to the touch and the directions say to make sure that when vacuuming, have the cord fully extended- not rolled up. My vac has not tripped breakers. Though this thread certainly does not apply to those with 50 amp systems, the 30 amp peeps might still be wondering about this. It is true that you have to consider what model of AC you have and its current draw.

[OTRA15]

rodsterinfl FYI there is a newer thread with a good discussion of similar issues. Is 30 Amp Really Needed:

http://www.airforums.com/forums/f37/...-150863-3.html