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AH64ID's avatar
AH64ID
Explorer
Jul 08, 2017

A/C or generator issue??

We just got back from a week of camping and have a new issue.

I have a Coleman 13.5K BTU A/C and a pair of Honda EU2000i's.

Over the course of 4 days an issue developed and got worse as the days went by.

The first day I was running my A/C and after about an hour the 20A breaker tripped. I heard the gen's rev up but they didn't go into overload before the 20A breaker inside the camper tripped. I reset the breaker and restarted the A/C. It ran fine for several more hours.

The second day the same thing happened and I reset it again, and realized that is was more than a coincidence at this point. It ran fine the rest of the evening.

The third day I hear the gen's rev up and then the overload tripped on the gen's instead of the breaker popping inside. I was actually inside the trailer when this happened and noticed some other things at the same time. During the 3-5 seconds that the gen's reved to max and the overload tripped I saw the fridge switch back to gas and the converter shutoff, but the A/C fan kept running at a very reduced speed. The A/C compressor didn't seem to be running. The compressor may have been humming but it was hard to tell over the sound of the gens and A/C fan.

So I had a voltage issue!! I wasn't sure if was a gen output issue or a A/C draw issue. At this point I started looking more into the issue. We took a small chest freezer with us and I wondered if the chest freezer was cycling and lowering the generator voltage to a point where the A/C compressor would stop and require locked rotor amperage, so I took the chest freezer out of the equation and it still made the generators go into overload protection mode. It sometimes would run 5 minutes and sometimes as much as 15. I'm not sure what was cycling to cause the issue.

Since day 2 I have only had it trip the generator overload protection and not trip the 20A A/C circuit break.

On day 4 I turned off all the AC loads and ran the A/C. It ran fine for over an hour. As soon as I turned the converter back on it caused the same low voltage issue. Oddly enough by switching the A/C from high to low fan allowed the compressor to get back up to speed and it didn't trip the overload circuit. I cycled the converter with the fan on low and it happened again, so it's not a function of the fan on high.


Now that we are home I am back into troubleshooting mode. I cannot get the voltage to drop or the breaker to trip on shore power, but that alone doesn't tell me it's a generator issue as shore power can overcome high amp draws easier if it is a A/C issue.

I got the gen's to go into overload protection mode and just before they shutoff they were holding 85V, hence everything dropping off and the fan slowing down. Same thing where it sounds like the compressor isn't running but it could be buzzing like it wants to.

I haven't been able to make the 300w fridge cause the low voltage issue but it seems to me it was the only thing that could have been cycling when the problem occurred. I am able to induce the issue with the converter and 400-500w of draw from it.

I have messed with each generator individually and cannot get them to have a low voltage issue. I have only put 1500w of load on them but if I have a issue it should still manifest.



Any thoughts on what's causing the issue?

Run Capacitor?

Generator?

I don't think it's the compressor as the breaker doesn't ever trip on shore power.


Thank you

10 Replies

  • newman fulltimer wrote:
    how old is the battery? sounds like the batt was loosing its amps converter kicking in full power pulls more amps but the ac breaker is the hit weak point and pops.


    How does it sound like that?

    I said it happens with the converter breaker off and with the converter only charging at 0.1 amps. Batteries and converter are fine.
  • how old is the battery? sounds like the batt was loosing its amps converter kicking in full power pulls more amps but the ac breaker is the hit weak point and pops.
  • Yes it has a hard start cap, and as I have said it starts just fine and can run for a long time without an issue, even at a high load. Once an A/C unit is running the start capacitor is no longer in play. The A/C staring is by far the biggest amp draw and it will start with the fridge on, converting pushing 30A, and other AC loads without issue.

    I've been using it in these conditions for years, something isn't working right. The generators are barely above idle and then they go to max load.

    Peak output is 4000w is parallel mode. The reduction for altitude is in horsepower and if the generator is able to rev up and trip the overload circuit it has enough horsepower to make full power. When a generator is horsepower limited it won't be able to trip overload as the rpms won't allow for it. It's not a ambient conditions issue. It's an output or an A/C issue.

    I'm considering ordering a run capacitor.
  • 6000 ft and 85 degrees is no joke. 63 LRA is also huge.

    Does the AC have a hard start cap?

    That density altitude is almost 9000 ft which would be 27-30 % lower output from the generator.
  • I don't have an AC water heater.

    Nothing has changed or added to the AC system.

    Today it was happening with the fridge off and the batteries accepting a large 0.1 amps.

    Until there is an induced voltage fluctuation the A/C draw is normal. Sometimes the A/C can handle the fluctuation and sometimes it can't.
  • Is the water heater on, whereas it wasn't before this issue? Does it still do this if the fridge and water heater are in gas mode?
  • It has happened at 6000' and 80-90° and 2700' and 90°.

    It's been a while since I looked but the wattage is 1800-2000 (depending on temp and voltage). The locked rotor amps are 63, which could be what it's pulling when the compressor "stalls" while running.

    This is my 6th season with this setup. It's a new issue and not ambient temp related.


    I also realized I didn't add that it always starts fine, with minimal voltage drop and no issues regardless of what else is running. It's just something that causes a voltage drop while running that does it.

    I did also notice one other thing once. During one "incident" the compressor seemed to shut itself off. No overload protection or circuit breaker trip. I went and cycled the thermostat to enable the compressor delay and sat up on the roof next to the A/C. After the compressor delay ended I heard the relays click on the unit but it wasn't until about 2 minutes later that the compressor started. It started without issue. It makes me think there is a thermal switch???

    I also don't hear a steady increase in amperage from the unit. It's an all or nothing increase.


    EDIT: Just to clarify. It feels like if there is a slight voltage drop from a new load that the compressor "stalls" and thus is pulling locked rotor amps.

    What I am not sure is if it's being caused by one of the two generators or from the compressor/run capacitor.... or something else.
  • What was the temp and altitude?
    I assume 2 hondas make 3200 running watts and 4000 surge, at sea level 60 degrees ambient.

    Next how many running watts does your Coleman use, and surge/locked rotor amps?
  • 2oldman wrote:
    Didn't you just say it was the converter?


    No, I said the load from the converter is adequate for inducing the issue.

    It's not a converter issue as far as I can tell.


    EDIT: Just to be 100% sure I went out and was able to recreate the issue with an air compressor and the converter circuit breaker off.