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gregaiken's avatar
gregaiken
Explorer
Aug 15, 2014

13,500 btu air conditioner - how to power?

we have access to a Winnebago 1995 Itasca Passage 23RC.
this has a 'roof mounted' 13,500 BTU central cabin air conditioner.
the Winnebago does NOT include the 'specially-designed-to-fit' OPTIONAL gasoline-generator unit. we desire to supply power to this A/C unit and are in a time crunch to figure out options... my questions...

1. i read at rv.net that 'steady state' (120 vac) amperage for the AC unit will range from around 12 to 15 amps. no one has said what is the 'start up' amperage. this would be important to know if we were to spec out purchasing/installing any power generator source.

2. the spec sheet for this RV states there is a '9 amp 120 vac breaker' as a part of the main power system. i infer that this breaker has nothing to do with the ampacity required for the AC unit - that instead, this would be for other user items. and infer that the circuit for the air conditioner is seperate from the 120 vac circuit for other user items. can someone confirm, or elaborate.

3. even if one had an appropriate power source, where exactly would one 'connect this power' to the AC unit?

4. the most important question is the following - what options exist to supply power to this AC unit?

a. purchasing the oem Winnebago gas power generator seems to not be an option - as ive heard this costs around $3000. beyond our budget.

b. are there 3rd party vendors that make a comparable gas generator to fit the space on this model that provides suitable power? if so, what models would work?

c. i know very little about this RV's battery system. is it conceiveable to hook up a DC to AC sine wave inverter to provide the required ampacity? if so, my concern is that the ampacity draw for the AC might exceed the RV's ability to charge this battery with the alternator. in otherwords 'more current being required, than is able to be supplied' - thus putting us in an 'unable to fully charge the batterys' predicimant.

d. someone suggested, 'just buy any gas generator, and one of those trailor hitch extensions that add sort of a floor extension at back of rv. place the 'purchased from anywhere' gas generator there, and it should be ok for you to run it as you drive on the highways'. i was warned these can be obnoxiously loud, and i kind of doubt that this would be legal to have a running gasoline electric generator operating as we are driving on the streets of america. any comments on this?

if anyone could speak to our concern, this would be greatly appreciated. maybe there is some way to speak by phone? im not sure how this would work - but we need a solution fast, as a trip is planned in less than 2 weeks.

any help or info woudl be greatly appreciated.

greg
Class A
  • dave17352's avatar
    dave17352
    Explorer
    Aug 15, 2014
    I would purchase the best possible generator you can afford and mounted on the back of the rig just like somebody else said, I think you're going to need at least a 3000 watt generator to run that as a 3000 watt generator will run my 13 5 and 15 K ac with not a whole bunch of power to spare. I don't think there would be any problem running the generator going down the road.
  • time2roll's avatar
    time2roll
    Nomad
    Aug 15, 2014
    Does noise matter? Are you camped close to others where noise matters to them?

    Otherwise you generally need 3500 to 4000 watts minimum.

    Only the built in option is going to run in the compartment. Any portable will need to be hauled out into the open for operation.
  • ksg5000's avatar
    ksg5000
    Explorer
    Aug 15, 2014
    Your RV comes with a power cord that supplies electricity to your air conditioner, microwave etc. The power cord likely has a 30 amp male connector and many/most campgrounds will have a matching power supply - but purchasing a "pigtail" which converts the 30 amp male connector into a 15/20 amp std connector is a must. If you need an extension cord get the fattest one available - makes a big difference if your running an air conditioner.

    Your air conditioner takes about 20 amps - but will run off a 15 amp outlet with a number of proviso's (no other appliances on that circuit, your rig isn't using other electrical stuff (elect hot water, microwave, elec fridge, battery charging etc). You should also monitor the voltage while the Air Conditioner is running and turn it off if you see voltage drop below 109/110.
    .
    If you buy a Generator your neighbors will appreciate your buying a quiet one - and yeah - they cost more.
  • Sandia_Man's avatar
    Sandia_Man
    Explorer II
    Aug 15, 2014
    With our onboard Onan generator there is an 30 amp outlet where we plug our shorepower cord so that the entire rig can have power. We often run the generator to power the AC unit while driving down the road.

    I don't believe any of the portable generators ( you will need at least 3000 watts for AC usage) are deigned to run within a rig's prepped onboard generator space, somebody else with experience would have to chime in on whether a portable can be used on a rear mounted carriage while driving down the road to power the AC.

    You would have to carry a heck of a lot of batteries to power 13.5K AC unit (via inverter) and it wouldn't do it for long anyway, plus as you mentioned, there would be the issue of recharging them and alternator will be hard pressed to do the job.

    Hope you can figure out a way to get it done. As you stated, onboard generators are quite expensive although it may prove to be the only reliable choice if required to run your AC while driving down the road. If you don't need that specific requirement, a 3000 watt (or higher) or a couple of 2000 watt (paralleled) portable generators would do the job nicely once at the campsite.
  • Golden_HVAC's avatar
    Golden_HVAC
    Explorer
    Aug 15, 2014
    The battery option is out. The air conditioner consumes about 1,400 watts per hour, and each battery can only hold about 1,000 watts. Also a sine wave 1,800 watt inverter is way out of your budget.

    Home Depot or Costco might sell a 4,000 - 4,500 watt generator that will power the RV fine. Noisy as heck, but so is the factory installed Onan. they are about the same amount of noise.

    The Honda 3000 is marginal on capacity, while it will start the cold air conditioner, once it is running, the pressures change, and the cold side is lower pressure, the high side higher pressure, and restarting it later in the day the compressor takes more power. This is why they say to let the compressor stay off more than 5 minutes between cycling it back on. Even so, the 3000 Honda can struggle with turning it back on.

    The honda is very quiet, kinda expensive, and fairly heavy, as are the 4,500 watt 'contractor' generators at Home Depot and Costco. You might be able to rent a Home Depot generator, something I have not tried yet.

    The hitch haul is something you can buy at Harbor Freight, so you have it locally. It fits into the 2" receiver on the back of the RV, cost is about $95, and will hold the generator. A cable lock will keep it reasonably safe, but generator theft is by people with bolt cutters, so beware.

    Fred.
  • MrWizard's avatar
    MrWizard
    Moderator
    Aug 15, 2014
    I have never seen a 9 amp 120v circuit breaker in any RV
    I don't believe that
    The start surge aka compressor locked rotor amps is approx 54 amps
    But that is only for milliseconds, you need at least a 3000w generator
    And will be limited to"ONE" big draw item at a time
    If running the A/C , you cannot run microwave or hair dryer, or coffee maker, or big vacuum clear
    You can very likely run coffee maker and microwave together if batteries charge level is up andand the microwave is not to powerful
    It's all about power management
  • naturist's avatar
    naturist
    Nomad
    Aug 15, 2014
    I agree, running that AC off batteries is out of the question. The AC would suck a single RV house battery dry in minutes; you'd need a semi full of them for a reasonable run time.

    The easiest and cheapest way to go is to get a 4,000 watt or bigger generator and just plug the RV's shore power cord into it. (2,000 watts is marginal for running the AC ONLY; 3,000 watts will often accommodate losses in the converter and run other things, but can be marginal for many folks; 4,000 watts will cover most all your needs.)

    If you can find a 4,000 watt, 120 volt only generator, that would be best, because a 240 volt unit that size will be using only one side of the 240 volt coils, and this can cause issues.

    I found an 1800 watt, 120 volt only, inverter generator at a pallet sale at Northern Tool a couple years ago for $200. It is fine for recharging the RV batteries when we go camp where there is no electric, but of course it is too small to run the AC. I caught a 5500 watt (6875 watt surge) open frame generator on sale a while after a big wind storm had knocked out power in our area for a week or so for $650 at Tractor Supply Company. It's big and heavy and loud, but plenty of muscle for the RV or for the house in an outrage provided we mind we don't try to run the electric clothes dryer or the electric water heater. So you can find generators on sale if you keep your eyes open.
  • gregaiken's avatar
    gregaiken
    Explorer
    Aug 18, 2014
    thanks everyone for the very helpful information!

    weve decided on putting on a hitch platform, bought a used generac 3000 watt model, will try to enclose it in a plywood housing with a top exhaust fan (pointing away from the vehicle) to manage: a. sound, b. visually shield it - to thwart theft, c. protect it from moisture (not that we expect rain at this time of year).

    somehow we will need to securely attach the power cable from the generator to the side of the RV. any thoughts of how best to do this without screwing in a fastener through the fiberglass siding? cable is rather heavy - i doubt small velcro patches will help.

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