Forum Discussion

Micro1706's avatar
Micro1706
Explorer
Jul 27, 2016

13,500btu a/c on a Yamaha 2400iSHC genny? Hard Start Kit?

We just got a new yamaha 2400iSHC genny, after being told it would power the 13,500btu Dometic a/c on our brand new Winnebago Micro Minnie 1706fb trailer. It did not! When the a/c kicked on the overload light lit on the genset and that was the end of that. The a/c then did not go on. And the generator has to be turned off once the overload light goes on, then re-started. The same process repeated, got the same results.
However, it was a very hot day here today...around 93, and the 1706 sat in the sun all day. When I ran the test, it was very hot inside the trailer.
so, decided to run a test: connected to city power, ran the a/c just fine, cooled down the innards of the trailer, then shut down the a/c, connected the trailer to the running genset, and yes, it ran the compressor just fine when I then turned the a/c on. And has been cooling it for the last hour.
Now...would it not be advisable to get a Hard Start Kit (something like this: Supco SPP6E E Series Electronic Potential Relay Style Hard Start Kit, 1/2 - 3 Horsepower Range, 88-106F Capacitor Size), as someone once suggested when we were considering the generator? If so, how does one go about this? Would it be advisable to take it down to the local r/v mech. shop and ask them to do the install?
I have been told it helps protect the compressor or extends its life. Is there much truth to this?
Any suggestions, advice, or insight will be very gratefully appreciated.
Many thanks
Bob

20 Replies

  • Having been to this movie before....

    I had a 2400is, and a coleman mach III (circa 1999) which was much less efficient. Once I put the supco hard start kit, I was able to start and run my AC without a problem. I was able to run it at sea level up to 6500' and it had enough to run it.

    What I didn't like about my 2400 was two issues:
    Weight (75lbs)
    No ability to disable ECO mode.

    When I sold my TT for my 5er, I sold the Genny and switched to my honda EU2000.

    My EU2000 with a hard start kit installed, and with ECO off, and with all the other "stuff" switched off (fridge, converter, etc), will start and run my AC at sea level, but if it's really hot (over 90 degrees) or at altitude (3000' or higher), the 2000 will overload after 20 minutes (which is the maximum it'll put out 2000 watts).

    All in All, I'm ok with my 2000, but eventually I'll purchase a second one to allow me to run my AC when I really need it.

    You MUST run your FAN for your AC (not ac running just FAN on) for about 5 minutes - and with the FAN switched to ON, switch the AC to ON. This allows you to energize the circuits and the load is only the Compressor - not the fan and compressor.

    If you get your AC running, set the temp as LOW as you can and don't let it turn off. Otherwise, it may not restart.

    You also need to be sure your dogbone adapter is equal insize to your power cable from you TT. If it's any smaller, it won't have enough capacity to move the amps needed through it. I had what I thought was a decent dogbone, (120 20 amps to 30 amps RV) and the wiring internally while not visible to my eye wasn't at least a 10 gauge wire and it restricted the flow of electricity. Which I Switched to a dogbone that was direct (female RV to Male 20amp) it worked.
  • j-d's avatar
    j-d
    Explorer II
    Chris Bryant has a link to the SailNet article I was referring to. See the RV.net thread linked above.
  • Almot's avatar
    Almot
    Explorer III
    Micro1706 wrote:
    Not sure if there is a difference between the dometic and the generic supco spp6E model.

    Other than the cost? ;)

    Keep in mind that AC is still 1,800W after it's started, and generator is mere 2,400W so you better shut the AC off when running microwave or a big coffee maker.

    I like the inverter solution the best. Getting "enough" boost from 2,000W inverter is more predictable than from capacitor of a limited capacity, no pun intended.
  • Many thanks for all the advice and suggestions.
    I am considering ordering the Dometic hard start kit, matched to this a/c unit. I am still not sure of the exact unit. the manual is the same for a list of model #'s, so I am awaiting further confirmation from winnebago as to the exact model # of the one I have. As soon as I have that, will order the corresponding h.s.k., and hope it corrects the situation.
    Not sure if there is a difference between the dometic and the generic supco spp6E model. Will do a bit more reading in that area also before ordering. If anyone has any opinion on comparing them, please advise.
    Am reading a very good past discussion on this same topic right here
    http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27618450.cfm

    Many thanks
    Bob
  • My generator is a Yamaha EF2800i. It's about 10 years old, open frame type but otherwise very similar to the 2400 model. Same engine, etc.

    It wouldn't run my Coleman Mach III A/C, unless economode was switched off. Even then, it was an iffy proposition. The SPP6E, along with a fan delay circuit, fixed things up excellently. And in my case, the hardstart cap was very easy to install. Literally plug and play.
  • j-d's avatar
    j-d
    Explorer II
    Wish I could find the article I saw a few years ago about running MARINE A/C on a Honda 2000 with various start kits. Marine is 120-VAC like RV but heat exchange is to water instead of air. I think the water pump is powered separately from the A/C so it doesn't figure into current draw, but the indoor blower probably does.

    They described the Honda 2000 as a "potent little unit" for its ability to run A/C. I don't remember which start kits they used other than that that pricey Dometic one did best.

    Aside from the article, there's debate over which SUPCO device to use. Chris Bryant has the most experience with those here, from his professional RV repair business, and recommends the "e" series such as SPP6e. Says it's nearly as effective as the "Starting Relay" kits that control the starting capacitor. SUPCO, on the other hand, says to use their standard PTCR - controlled one such as SPP6 if you're using a Generator. Their explanation is that the PTCR type gives the generator more time to respond to the sudden load increase of a compressor start. And that the "e" series takes the start capacitor out of play too soon. Chris, OTOH, remains adamant for the SPP6e.

    The idea of Fan Delay is to make more generator resource available to Compressor Start. You can run Fan without Compressor, but not Compressor without Fan, so you need to be sure the fan delay is brief. Fan running before Compressor Start would be better than starting both at once.

    It seems the Honda has more "grunt" than other small generators with similar ratings. Yamaha 2400 should do better than Honda 2000 but maybe not for starting a compressor.

    I hate to see you in this situation. If it was mine,

    1. Get a PTCR start kit with the right rating for Dometic

    2. Add a Fan Delay

    3. Run the Yammie with any "ECO" mode OFF
  • Does the Yamaha have switch to shut off idle control? In identical conditions, I tried new Yamaha 2400 from power sports dealer and said i'd buy it if it ran my pancake air compressor. It wouldn't. My used Honda 2000 would. I would empty all air psi from tank, have to switch from idle (eco) mode to full rpm on Honda, and instantly ( while throttle opened up and rpm ramping up) turn on the compressor switch and less than 75' F Honda would run compressor. The Yamaha 2400 wouldn't. I feel 2 reasons, Yamaha was brand new and no breakin time (maybe stronger after loosened up) and no eco (idle) off switch I could use to ramp up rpm immediately before I turned on air compressor switch. Conclusion new Yamaha 2400 wouldn't run it and my used Honda 2000 would. Identical conditions. Salesman walked away impressed with Honda. They sell both brands. He had nothing to lose.
  • if you have brisk air II your hard start kit needs to be rated 43 - 53 uf. the kit you stated is the uf for coleman/rvp/airxcel. Dometic number D3310727.015 hard start kit. unsure of supco number compatible for dometic. I haven't researched that!. Will your gen run that I don't know. I don't have your generator. I do know my used Honda 2000 outperformed a new Yamaha 2000 as Yamaha wouldn't run a shoreline attached rv with 120 vac water heater on , as it would surge and labor down rpm within 15 seconds and trip overload, and my Honda pulled hard and hung in their. Maybe a couple hours on Yamaha would helped after breakin time on engine.
  • Almot's avatar
    Almot
    Explorer III
    Some years ago Dave did exactly what you are planning to. With the same Yamaha. I think he is right that there are some 13.500 AC units that are beyond any help.

    Dometic makes such a kit too, called "smartstart soft starter", though the cost is ridiculous.

    Slightly different way to skin this cat, using hybrid inverter: Video
  • I had my local dealer order-up a 2400 with the agreement that if it started and ran my AC I would purchase it. I had the hard-start kit and fan delay relay installed. Almost sea-level and 100 degrees. The 2400 would NOT start and run my 13,500 AC Unit. I bought two Honda 2000's and all is good. Chino