Generator size needed to start 11,000 BTU truck camper A/C?

So I bought a 1600 watt inverter Yamaha with 2000 watt surge. It would not start the A/C using a 110 outlet. Hoping the 220 outlet does the job. I had been running the AC off of grid power 110 so I "figured" it was about 12 amps ~ 1500 watts.

I'd just check but having some peculiar health issues. It is a 2012 Forest River Palomino truck camper rated at 11,000 BTU. FWIW - modern truck campers take a while to know your way around.
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries

Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,726 admin
    edited July 7 #2
    The easiest temporary fix/trial is to get an old 50-100 foot light duty extension cord and plug it between the genset and the A/C unit and see if the added resistance will drop the starting current.

    In general, inverter generators, have poor surge performance (past rated value)... Plain Jane gensets will simply lug through a "heavy starting surge". An inverter-generator is "electronic" AC output and can shutdown in milliseconds and will not "lug" through heavy starting surges.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • softdownsoftdown Solar Expert Posts: 2,695 ✭✭✭✭
    BB. said:
    The easiest temporary fix/tratrial is to get an old 50-100 foot light duty extension cord and plug it between the genset and the A/C unit and see if the added resistance will drop the starting current.

    In general, inverter generators, have poor surge performance (past rated value)... Plain Jane gensets will simply lug through a "heavy starting surge". An inverter-generator is "electronic" AC output and can shutdown in milliseconds and will not "lug" through heavy starting surges.

    -Bill
    Great answer as always. I was hoping that simply using the 220 volt outlet on the genset would make the A/C work fine. Though that seemed suspicious for some reason. The genset "advertising" fails to even mention 220 volt applications. 

    If I can't make it work I can return it for a larger, cheaper and simpler unit that also accepts propane. Though propane is less energy dense and would lower the output by ~ 20% by my estimation. Shame in a way - I really like the inverter generator. Super quiet and seems well made. I just can't justify ten gensets. My others are too small or too heavy for truck camper usage. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • BB.BB. Super Moderators, Administrators Posts: 29,726 admin
    edited July 7 #4
    If it is the Costco inverter-genset:

    https://www.costco.com/A-IPower-1600W-Running--2000W-Peak-Yamaha-Powered-Gas-Inverter-Generator.product.100343958.html

    That twist lock connector is a 120 VAC 30 Amp unit intended for simple plugin to RVs that have 120 VAC / 30 Amp twist lock...

    As far as I can tell, that is not a 240 VAC output on that genset.

    -Bill

    I am guessing it is in the NEMA L5-30P family...

     https://www.amazon.com/L5-30P-Plug-NEMA-Locking-Amps/dp/B004XHWHHU
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • softdownsoftdown Solar Expert Posts: 2,695 ✭✭✭✭
    BB. said:
    If it is the Costco inverter-genset:

    https://www.costco.com/A-IPower-1600W-Running--2000W-Peak-Yamaha-Powered-Gas-Inverter-Generator.product.100343958.html

    That twist lock connector is a 120 VAC 30 Amp unit intended for simple plugin to RVs that have 120 VAC / 30 Amp twist lock...

    As far as I can tell, that is not a 240 VAC output on that genset.

    -Bill

    I am guessing it is in the NEMA L5-30P family...

     https://www.amazon.com/L5-30P-Plug-NEMA-Locking-Amps/dp/B004XHWHHU
    That all makes perfect sense. No surprise at all though one tends to expect 220 volts from a 220 volt type outlet. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • BB.BB. Super Moderators, Administrators Posts: 29,726 admin
    That L5-30 is a common 120 VAC @ 30 amp connector... It would never (on purpose) be used on 240 VAC.

    Besides RV, a lot of shops and construction use 120 VAC twist locks too.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • softdownsoftdown Solar Expert Posts: 2,695 ✭✭✭✭
    Turns out that many voltage regulators have a tiny brass screw on the inside that easily adjusts voltage output. Changed my Onan 3500 from 103 volts to 123 volts by turning that tiny screw - many times. 

    The Onan 3500 was made in China using a pretty good knock off of a Honda 2000 motor. Other problems presented and the partnership was terminated in favor of Yamaha. Tried to find my old thread about the Onan and lacked the technique to find and update. Least I did something. 

    Some would say that my campers 11,000 BTU air conditioner may have a 3000 watt start up surge though I doubt this is highly accurate.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Blackda3Blackda3 Registered Users Posts: 10 ✭✭
    Perhaps the following will be of interest.  I have a Dometic Cool Cat 10.5k btu air conditioner in my Aliner camper.  I made three test runs to measure my surge and running values - see below.  I used two 2017 Honda 2000 generators (the primary and the companion units).  Since then I have added a MicroAir smart start which allows me to run this load on a single generator. According to the manufacturer the MicroAir learns the start-up compressor's requirements with a full load which allows it satisfy the compressor's requirements using a smaller power source.)  I have yet to perform the same test with the revised system.  I can report that it does work but the A/C used to start instantly and now it takes a minute or so before it ramps up to output cold air.  

    The Honda's provided 120 volts AC:
    Start-up/Surge: 44.1 amps for less than half a second; 
    Running:  9.3, 9.87 and 10.0 amps (each run had a slightly different value);
    Once the A/C cycled off the fan alone was drawing 2, 2.48 and 2.47 amps.
    1996 LX450; 2017 Aliner Explorer: 3 x 105 Ah AGMs; 2 x 140w Kyocera panels connected to a Bogart TriMetric and solar charge controller; Remote deployable system of two/three additional Kyocera panels connected to a Victron MPPT 100/50 Solar Charge Controller.
  • softdownsoftdown Solar Expert Posts: 2,695 ✭✭✭✭
    Blackda3 said:
    Perhaps the following will be of interest.  I have a Dometic Cool Cat 10.5k btu air conditioner in my Aliner camper.  I made three test runs to measure my surge and running values - see below.  I used two 2017 Honda 2000 generators (the primary and the companion units).  Since then I have added a MicroAir smart start which allows me to run this load on a single generator. According to the manufacturer the MicroAir learns the start-up compressor's requirements with a full load which allows it satisfy the compressor's requirements using a smaller power source.)  I have yet to perform the same test with the revised system.  I can report that it does work but the A/C used to start instantly and now it takes a minute or so before it ramps up to output cold air.  

    The Honda's provided 120 volts AC:
    Start-up/Surge: 44.1 amps for less than half a second; 
    Running:  9.3, 9.87 and 10.0 amps (each run had a slightly different value);
    Once the A/C cycled off the fan alone was drawing 2, 2.48 and 2.47 amps.


    That start up surge is about 5300 watts. What size is your Honda? I've seen a number run their A/C with gensets over 2000 watts - that seems to be the size needed. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • BrianMoserBrianMoser Registered Users Posts: 3
    edited November 7 #10
    I do realize that this subject has been discussed many times here. As a matter of fact, I did a search and found a lot of information. However, most of what I found is for 13,500 BTU or 8,000 BTU AC units.

    My unit is 11,000 BTU and I need to know how many watts will require to run on a generator. I searched the web and found the following technical information about my unit:
    -->Electrical Rating: 115VAC/60hz/1PH
    -->Compressor Loaded Amps: 9.5
    -->Fan Motor Loaded Amps: 3.1
    -->Compressor-locked rotor amps: 53.0
    -->Fan motor-locked rotor amps: 8.8

    According to the Honda website, click here, for an 11,000BTU unit, I need 1,600 starting watts and 1,010 running watts.

    After playing with the Amps X Volts = Watts and Watts / Volts = Amps formulas, I can't come up with the same numbers, which is why I'm confused.

    Based on my research, it seems to me like Honda generators are the king, however, I am also considering other manufacturers due to the cost of this investment. Size is also a big consideration because my Truck Camper doesn't have any storage big enough for a generator, so it will be mounted permanently outside and I want to keep it as small as possible.
    Experience is what you get when you didn't get what you want
  • mike95490mike95490 Solar Expert Posts: 8,471 ✭✭✭✭✭
    For an inverter generator you use both Fan & Compressor Locked rotor amps.   inverter generators have little/no extra overhead.

    For a old school alternator generator , you can likely use double the Fan and Compressor loaded amps, to calculate your starting watts
    old school generators have a flywheel which can help the engine manage a 1 or 2 second overload

    These are "seat of the pants" guesses, since every generator / air con combo will be a bit different, some stagger turning the two motors on, some don't

    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • mcgivormcgivor Solar Expert Posts: 3,167 ✭✭✭✭✭
    edited November 7 #12
    Could you not rent, borrow or somehow aquire a Honda and test it to confirm it is up to the task? Information provided on websites whilst helpful, its not as valuable real world testing. 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • softdownsoftdown Solar Expert Posts: 2,695 ✭✭✭✭
    I find that gensets over 2000 watts are a bit large and heavy to be putting into a truck camper. Not to mention the major space needed - especially if you have a slide out. I addressed this major issue with two inverter gensets that run in parallel. 

    Honda gensets are among the very best. If a user plans on racking up hundreds of hours of needed usage the Honda investment is likely to prove wise. Quality gensets are also attractive to thieves who tend to have discriminating tastes. Use locks as needed and plain covers instead of Honda covers. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Blackda3Blackda3 Registered Users Posts: 10 ✭✭
    edited November 9 #14
    Sorry - I didn't realize my post was repetitive to this thread.  Apologies.
    1996 LX450; 2017 Aliner Explorer: 3 x 105 Ah AGMs; 2 x 140w Kyocera panels connected to a Bogart TriMetric and solar charge controller; Remote deployable system of two/three additional Kyocera panels connected to a Victron MPPT 100/50 Solar Charge Controller.
  • t00lst00ls Solar Expert Posts: 229 ✭✭✭
    I am having good luck with my 6250 inverter generator from champion power equipment, plus the fact they are US made and a US company

    they have some smaller units that can do bi-fuel https://www.championpowerequipment.com/product/100263-3400-watt-dual-fuel-inverter/#product-img-3

    and the regular ones https://www.championpowerequipment.com/product/75537i-3100-watt-wireless-start-inverter/

    or if you want smaller and do a parallel setup


Sign In or Register to comment.