AC tripping generator

[webgodfrey]

I have at 15k Dometic rooftop AC on my 5th wheel and using a 3500 watt generator. The AC seems to surge or cycle fast and trips my generator to overload. It did the same thing to my buddy’s generator when we hooked it up to his. We hooked his AC up to my generator and it worked fine. When I connect my camper to a direct power source, the AC works but I can hear it cycle too fast sometimes. I always use the 30 amp cable and not an extension cord. What could be making the generator trip?

[Kirk W]

Welcome to the Escapee forums. Based on what you describe, there is no doubt that your air conditioner is the problem. It should draw about 12 - 15A when the compressor is running and perhaps half of that when just the blower is running. You will need a clamp-on ammeter to do real trouble shooting but what you did with the load swap with your buddy is a good start. That eliminates your generator. I don't know what you mean by it cycling too fast but it may be that it isn't leaving the compressor off long enough for the refrigerant pressure to drop before it starts again, which would cause a big jump in starting current. 

[webgodfrey]

It starts then revs the generator as the compressor first kicks on then drop voltage. But I can tell that it tries to cycle off and on too soon. That’s when the generator trips. 

[oldjohnt]

The genset is tripping due to excess current surges but I bet you already know that...……..

AC is NOT my cup o tea at all but I'm sure some HVAC techs might answer your question.........… What little I do know is if the AC compressor tries to start up against too high head pressure it can stress your genset and maybe trip its breaker. The T Stat controls should prevent any short cycling where the compressor wasn't off long enough for pressure to bleed off and starting attempts would over tax the genset.

That being said and its a much easier and cheaper fix (Don't need whole new AC or compressor) IS THE START CAPACITOR is defective. They can be purchased at like Graingers or elec supply houses.

Sooooooo not knowing the problem Id look into a faulty capacitor to begin with as that's easier n cheaper to deal with....

The HVAC gents can better answer your question. Im thinking like Kirk an AC versus any genset problem for now  

John T

Edited July 23, 2019 by oldjohnt

[webgodfrey]

Thanks John!  I was thinking (hoping) it’s a capacitor issue. Even if that’s not it, replacing the capacitor would be cheaper than every taking it in for diagnostics. 

[beemergary]

If i want to shut mine down from cool. Cool-fan-off-heat. You have too go straight to off real quick. Anytime spent at fan will kick out generator or trip breaker. Must have to do with what oldjohnt said. Maybe best to turn up thermostat till it kicks off then turn off.

[Kirk W]

10 minutes ago, webgodfrey said:

replacing the capacitor would be cheaper than every taking it in for diagnostics. 

No doubt about that. The other problem is that many RV techs are not all that good with air conditioners. It is an area that they just don't get much practice working on. 

[webgodfrey]

True. I did some research then call the service desk at an RV dealership. They said to contact and HVAC tech. 

[oldjohnt]

9 hours ago, webgodfrey said:

Thanks John!  I was thinking (hoping) it’s a capacitor issue. Even if that’s not it, replacing the capacitor would be cheaper than every taking it in for diagnostics. 

Keep your fingers crossed HOWEVER Murphys Law is working against you lol

"They said to contact and HVAC tech" 

 That's what I have resorted to in the past versus any RV dealer AFTER I determined it was more serious then a capacitor. CAUTION those store a pretty good charge and need to be properly/slowly discharged with a resistor !!!!

 John T  Again NOT an HVAC guy so don't take much heart in my lay AC opinion

 

 

[Kirk W]

8 hours ago, webgodfrey said:

They said to contact and HVAC tech. 

At least they were honest about their lack of knowledge. I'm not sure that you will find an HVAC service that works on RV units, as very few do but if you find one they will probably be better than most RV techs. You may also want to try calling a mobile RV tech or two as it has been my experience that most of them are better qualified than the average RV dealer's shops.

[SCClockDr]

As others have stated above it appears your compressor is getting hard to start. Some have suggested to swap out the start capacitor if present.

Might I suggest an alternate approach. Hutch Mountain Run AC with 1 Generator - Micro-Air Easy Start 364 This is a Magic box that once installed will learn your compressor electrical characteristics over 5 shorepower starts and then will run on 1 Honda EU2200i in ECO mode. If there should develop an additional load, toaster, hair drier, microwave, etc. this gizmo will interrupt the AC till conditions improve. Generator and EMS if present will not trip & dump the trailer.

I just installed 2 Honda EU2200i Generators to replace a 12YO EU3000i (failed inverter) and found I needed both generators paralleled and @ full throttle to start the AC compressor or the EMS would open the contactors on low voltage. I installed the Micro-Air unit and I can now start & run the AC on a single EU2200i with the fridge on AC & PD converter in trickle mode with a few amps to spare.

 

This is not a cheap solution but if your compressor is indeed on its last leg it will buy you time to save & plan a replacement & just move the Micro-Air to the new AC unit.

I'm just a very satisfied customer with no other connection to the Micro-Air or Hutch Mountain organization.

Edited July 24, 2019 by SCClockDr

[joshdoe]

On 7/24/2019 at 8:53 AM, SCClockDr said:

As others have stated above it appears your compressor is getting hard to start. Some have suggested to swap out the start capacitor if present.

Might I suggest an alternate approach. Hutch Mountain Run AC with 1 Generator - Micro-Air Easy Start 364 This is a Magic box that once installed will learn your compressor electrical characteristics over 5 shorepower starts and then will run on 1 Honda EU2200i in ECO mode. If there should develop an additional load, toaster, hair drier, microwave, etc. this gizmo will interrupt the AC till conditions improve. Generator and EMS if present will not trip & dump the trailer.

I just installed 2 Honda EU2200i Generators to replace a 12YO EU3000i (failed inverter) and found I needed both generators paralleled and @ full throttle to start the AC compressor or the EMS would open the contactors on low voltage. I installed the Micro-Air unit and I can now start & run the AC on a single EU2200i with the fridge on AC & PD converter in trickle mode with a few amps to spare.

 

This is not a cheap solution but if your compressor is indeed on its last leg it will buy you time to save & plan a replacement & just move the Micro-Air to the new AC unit.

I'm just a very satisfied customer with no other connection to the Micro-Air or Hutch Mountain organization.

Twice that. Instead of buying a large generator that was hard to move around, I opted for two 2000 watt Champion (found them at Costco, perhaps not the gold standard of the Honda, but for way less money) generators that actually only each offer 1600 watts of clean continuous power.  I too use a parallel cord so that I get the benefit of the two and they run my A/C just fine, even at higher altitudes.  Having two gives me the option of running just one when I don't need to use the A/C and makes them very portable, even when needing both.

Back to the question, I have another idea. Though it might be an absurd one.  I have experienced the same problem (cycling too fast) with our 13.5K Duo Therm Brisk Air running on a Portable Honda EU3000i. If your thermostat is like mine, try to switch thermostat to a warmer setting: our cooling used a very fast motion from the start which made generator overload.

Edited July 26, 2019 by joshdoe
added my model

[oldjohnt]

Those soft start units are indeed great but costly. Regardless if you purchase one or not if the AC needs a new start capacitor CONSIDER TRYING THAT FIRST, its sooooooooooooo much cheaper if all you need is to get it working with the equipment you currently have.

PS I have no way knowing if your AC has a capacitor or some other problem or any problem at all. I'm ONLY saying if it happens to need one I would still get that fixed regardless. 

John T

Edited July 24, 2019 by oldjohnt

[Kirk W]

A soft start unit will not solve the issue of too frequent compressor cycling and I highly doubt that a start capacitor will either, but John is right that one doesn't cost much and is easy to replace. Use care handling it because they do bite, hard! If your compressor is cycling on and off in a very short period, there is some sort of control problem. 

Edited July 24, 2019 by Kirk W

[MichaelCrosley]

Hey Guys,

I am looking for best RV Generator and I have also search on google and found some of the review sites like https://www.trustedhints.com/best-rv-generator/  please tell me which one is the best generator for me from this site.

Thanks in advance,

Michael Crosley

 

[oldjohnt]

1 hour ago, MichaelCrosley said:

please tell me which one is the best generator for me from this site

 I just cant answer that specific limited question, I have no way of knowing "your" needs and what's best for "you" and would like to see more brands reviewed, however, I will render a few general opinions which may or may not help in your decision: FWIW You Tube and other RV forums have more in depth and brand choice reviews you might want to take a look at

 

  1) I much prefer an Inverter style Generator.

  2) If you need enough power to start and run an AC unit, I prefer at least a  3000 continuous watt unit, but even if

       you don't need that  much power Id still suggest at least 2000 continuous watt Inverter style for general RV

       purposes.

   3) Installation of a soft start unit might make it possible for a lesser powered genset to start/run an AC and helps

        a genset start an AC  unit regardless.  

   4) Remote start capability is a handy feature as well as electric versus pull start.

   5) Although its NOT to your question and is NOT one of those reviewed,  I would consider brands such as Honda

        and Yamaha, and  Hyuandi although some may be more expensive

  6) Size and weight and noise levels are also  MAJOR considerations in my opinion.

 

       Your money your choice best wishes

   John T 

Edited July 28, 2019 by oldjohnt

[Kirk W]

Welcome to the Escapee forums. I have no experience with the people whose ratings you list but I do very much disagree with them. My favorite rating service is Consumer Reports and they list Honda and Yamaha as #1 & #2. Generators Org have the same 2 at the top as does Generator Grid. If you do a Google search you will find a long list of reviews and while they do vary as to how they rate the different brands, Honda is at the top in most cases and Yamaha is nearly as well rated. I have experience with the Honda and I can tell you that it has been reliable and easy to start for many years. Both Honda & Yamaha are expensive, but quality always costs more. I would also strongly suggest that you only consider the inverter generators because they are far less noisy and are more fuel efficient. When you budget you also need to ask yourself how much will you rely on it for power and how critical will it be. In my case, we live in a rural area where storms often leave us without electric power for periods and my Honda is vital to us at times so I spent enough to get the best. 

[oldjohnt]

5 minutes ago, Kirk W said:

Honda is vital to us at times so I spent enough to get the best. 

DITTO its odd some of the major brands highly favored and used extensively in the experienced RV community were not reviewed nor among the "editors choices" Oh Well to each their own I guess, wonder if the editor is an RV and genset user ?????

John T 

[Darryl&Rita]

You guys realize you're discussing what's likely a spammer, right? Never click on links in a first time poster.

[oldjohnt]

23 hours ago, Darryl&Rita said:

You guys realize you're discussing what's likely a spammer, right?

Thanks Darryl, It always pay to be cautious and diligent regarding spammers DITTO. I'm running more then one anti malware, spyware, virus and firewall protection schemes (in addition to backup) which may slow me down some, but I figure it's better to be safe then sorry. BEFORE any questionable website opens I get a red flag if it might contain Spyware or Malware or a Virus etc after which I have the option to open or not.  Fortunately, the link provided passed scrutiny (although can never guarantee 100% any such is perfect) and is indeed a Genset review site regardless of other possible problems or spam it may contain, HOWEVER, I didn't find it very useful or convincing lol

PS  my response is in general meant to apply to anyone considering a Genset for RV use and is applicable with or without referring to or visiting any other website or links whatsoever.

John T Live in the RV where I overnighted in a church parking lot in Stanton Kentucky, but now later Madison Indiana

Edited July 29, 2019 by oldjohnt

[John krupp]

I’m a retired industrial ac mechanic pull your. Ac cover wash out condenser with a garden hose  make sure your condenser fan is running ...good luck

[Jennifer Ministries]

When trying to run my camper's AC through a generator it kicks the breaker just after a few second. I can plug it into a household outlet and the AC runs fine. I have tried up to a 5000 watt generator with similar consequences. I see much smaller generators running camper's AC all the time.

Any suggestions appreciated.

[oldjohnt]

2 hours ago, Jennifer Ministries said:

When trying to run my camper's AC through a generator it kicks the breaker just after a few second. I can plug it into a household outlet and the AC runs fine. I have tried up to a 5000 watt generator with similar consequences

    One thing that comes to mind is the short term SURGE CAPACITY of a given generator. Some quality brands may have more "actual" surge capacity then cheaper brands and surge capacity can be a sales gimmick which might be all hyped up. Still, it takes a fairly poor if actual 5000 watt (rated load right???) rated unit that cant start a good correctly working 13,500 or 15,000 BTU RV rooftop AC ?? Like you I have seen smaller rated gensets run an AC. There are You Tube videos (no guarantee of accuracy) of a Honda 2000 running an AC 

    Second thing that comes to mind is a faulty capacitor or other mechanical/compressor problem in the AC unit whereby utility power has sufficient surge capacity to start the AC while a genset just cant get over the hump.

    Third I have seen circuit breakers over time that get weak perhaps a new one might allow the AC to start ???

     Fourth, perhaps a soft start unit as discussed above may help, although I still see a problem if a decent sized genset can't get it started  

     Fifth they also make special circuit breakers (HACR I think??) designed specifically to allow AC units or other compressors to start up while not nuisance tripping which might cure your problem HOWEVER I have no idea if any such will fit and work in your particular RV brand and type power distribution panel 

     Finally perhaps the AC itself is the problem which a good HVAC tech may be able to solve. 

        SUMMARY  Insufficient Surge Capacity Genset,,,,,,,,,,,Faulty Capactor,,,,,,,,,,Weak Circuit Breaker,,,,,,,,,,,HACR Circuit Breaker cure,,,,,,,,,,,,AC problem ?????????????

      I'm runnin out of guesses lol maybe the more HVAC educated gents can add more ideas...………..

      PS are you running any other devices like a fridge or microwave or other high power 120 volt appliances when the AC tries to start ???   If so turn them off n see what happens 

      PS do you mean the distribution panel breaker or a breaker on the Generator?? I assume the regular RV panel 

    

    John T  NOT an HVAC guy so take this for what it is...……….   

Edited August 3, 2019 by oldjohnt

[Kirk W]

5 hours ago, Jennifer Ministries said:

Any suggestions appreciated.

I see much smaller generators running camper's AC all the time.

The problem could be either something in the a/c unit or the choice of generator. Keep in mind that not all RV a/c units are the same capacity and they have different power requirements. I have a small travel trailer and operate our air conditioner with power from a standard, 15a house outlet often and have powered it from a 2000 watt inverter/generator. Without being there with a clamp-on ammeter to see what the a/c is actually drawing we can only guess at what may be the problem. It would help some to know more about your RV and the a/c that you have. Does your RV have a 50a or a 30a power cord? What is the BTU rating of your a/c and what make and model is it? 

[SCClockDr]

17 hours ago, Jennifer Ministries said:

... it kicks the breaker just after a few second...

Hi Jennifer Ministries

As others have noted knowing which breaker is tripping would improve our ability to narrow down the issue & offer more accurate suggestions.

Without more info, I see 4 possible breakers involved depending on equipment installed.

1. Distribution panel Main breaker.
2. Distribution panel AC breaker.
3. Generator breaker.
4. EMS contactor (breaker)?

In my case the EMS contactor was opening on low voltage, the generators were still supplying power. A Micro-Air Easy Start device solved the issue and I can start & run the AC on a single EU2200i Honda with the fridge on electric & converter in trickle mode.

It will also interrupt the AC power should someone start the microwave, toaster, or coffee maker, etc. It will restore the AC once conditions improve.

The Micro-Air is $$$ but can be swapped into future AC units if a replacement becomes warranted.

Edited August 4, 2019 by SCClockDr
Correct auto correct