Generator overload - A/C problem

[Jeffr75]

Hello,

I just purchased my very first TT, its a 2020 Airstream 19ft Bambi with a 13,500 BTU A/C. I will be boondocking, so I need a generator. Airstream recommends a 3500 Watt, they don't say if that's starting or running, I'm assuming its running?

I recently posted a question about what size I really need, lots of people say you can run it on less but I ended up buying a Firman 3650/3000 here's what's happening.

A/C turns on fine, I started on the lowest setting, then I went to the second setting and finally the max. If I don't touch it it seems to stay on, the second I lower it or switch over to just the fan it overloads the generator.

I tried again, A/C turns on, I put it to the max and it works. I left it on the max and tried the microwave, I could hear the generator work harder but nothing shut off. I stopped the microwave, still ok. Then I tried to lower the A/C and it overloaded my generator again!

I tried a 3rd time with only running the A/C, and the same thing keeps happening. I can get it to turn on and stay on but the second I play with speed or switch to the fan it overloads.

I'm so confused. I figured it was a cheap brand and returned it. I went out and rented a HONDA Ultra-Quiet 3000i ES, because from all the reading most say this is more than enough. I had the same result.

What am I doing wrong? I'm scared to spend money on and even bigger heavier generator, or run 2 small ones with a combined 4400 watts. I've read that maybe I need a slow start or easy start device, or that in warmer weather the A/C needs a bit more juice. I think my A/C SHOULD run on the recommend 3500 watts generator even in warmer weather, shouldn't it?

Any help would be appreciated, sorry for the long post.

Thanks,

Jeff

[AirMiles]

I run my stock (no softstart) 15,000 BTU A/C on my Airstream everywhere in the country at any elevation without overloading my Champion 3450 Dualfuel generator on propane which is derated to 3150W. I can run everything in the Airstream with this generator just like when its plugged into shore power. I think there is a problem with your A/C and not the 3000W generator.

[GCinSC2]

Jeff

Have you conducted same test while hooked to shore power? Has it ever worked correctly?

I read you tried two generators, got it.

If this was in my driveway I’d hook up a test cable I made that allows use of clamp on ammeter and record peak starting amperage. Meter records peak amperage.

Other idea disconnect all ac power loads. All of them except ac and try again. Any connections after using and then power off of course hot to the touch?

Gary

[BayouBiker]

Bad news, you should have checked here before getting a generator.... I so don't want to write this.

First off, you need to dump the Firman even though we can make it work because it is a contractors/industrial generator and for camping so you don't upset your neighbors you need an insulated inverter generator. 15-20 dB more quiet. So since you need to get rid of that poor thing, I won't go into why you're having issues with it. If you are really curious, PM me and I will explain it.

The A/C draws 15Amps nominal and 17 if its really hot in the trailer. So a high quality 2200 Watt inverter generator will do the job, you just need some help at start up. So You can go with a true 2200 peak and a soft start kit added to the A/C or you can get a beefy 3500 like Airstream likes. Me, I like big and my wife likes her hair dryer and coffee maker, so I went 3500. I am also a cut dry person in a low budget land so I went with Harborfreight predator 3500. People here will scoff, but it is a beast and it is very quiet, and it tough as nails. I got two of them for just over the price of one Honda 2200 and I can run my A/C in the house after a hurricane. I am laughing all the way to the bank, these things have been with me for three years now and they are flawless. My wife takes a shower, with electric Water heater, powers her hair dryer, we run two A/C's and a coffee maker and those things don't bat an eye.


Edit: Lost power.... Thunderstorm

So pick your poison. but consider getting rid of the loud contractor generator.

Edit2: looking more at the Firman site, not clear I might be wrong. Perhaps you do have the inverter model.... If so please disregard.

[Jeffr75]

Thanks for the reply! I haven’t taken it to a campsite with power yet. I think I’ll try your last idea for now, to be clear, when you say disconnect all AC power loads do you mean shut off all the breakers except AC? Sorry this stuff is not my forte

[BayouBiker]

Okay, sorry for the screed in my prior post. the thunder and rain had me twitterpated.

Very odd what you describe. the Generators use a floating neutral and the trailer is not bonded. perhaps there is an issue with the blower neutral connection on lower speeds causing a current spike.

first thing to try is to bond the ground and neutral at the generator. You can do this by getting a 120 V 15/20 Amp male extension cord repair plug and just use a short wire to connect the ground to the white neutral. Plug that into an available slot on the generator.

[GCinSC2]

Jeff

Yes turn off all breakers but ac. I bet it’s marked as ac. 12VDC batteries need to be charged and powering trailer for thermostat I bet.

But you have a 2020. Did you buy new or used?

If bought new, contact selling dealer and discuss or if close by go back and make them prove working correctly. Were trailer features demonstrated like AC at delivery?

Do you have any surge protector or energy management system? Just curious.

If not comfortable working with 120VAC don’t take risks.

Gary

[Bill M.]

Plug it into a 20 amp or more shore power outlet and try the AC. It sounds like you could have a problem with the AC unit. Do you plug it in at home to charge the batteries?

The Honda 3000 has plenty of power to run the AC and everything else in the trailer at the same time. Something else is shutting you down. Are you using a surge protector or does the trailer have a built in EMS?

If your batteries are discharged quit a bit when you are boon docking then you are putting a heavy amp load into the converter as well as the AC.

Most likely a Honda 2200 will start and run that AC if the power converter is shut off. It will start easier with the Easy Start installed but ours would also run without it.

You do need an inverter type generator. They have more power for starting a load like an AC.

Does your AC also have a heat strip? Are you turning on the heater and the AC at the same time? Changing fan speeds should make no change in the load. So I suspect there is something wrong with the AC or in your operation of it. Be worth getting a hookup campsite to test it all out on a 30 amp connection. But really the Honda generator should have worked for that.

[Jeffr75]

I have not plugged it in at home, but I will. I do have a solar panel and I assumed this would keep my batteries charged, the battery level is 13.6. The dealer said anything above 12 is good.

No surge protector or ems. The unit has a heat strip but everything is controlled by the same dial. I can turn on the heat, the AC or just the fan. I’m waiting on the dealer to get back to me as I bought this new and they should be able to help. I’m also going to get to a campsite and plug this in to shore power and see if everything works. I really wanted to verify if the Honda should power everything even without a slow start or easy start device. Thanks everyone!

[Jeffr75]

So I thought about what I could be doing wrong because I am able to start the AC without any lag in the generator or struggle. The issue starts when I quickly change the fan speed or temperature.

I tried taking things a bit slower and I'm having success. I can turn on the AC no problem, I waited a 2 minutes then adjusted the temperature, still works, waited another 2 minutes, changed the fan speed, then ran the microwave. I can basically do everything without any overload if I take things slow. If I change the fan speed and temp within seconds it overloads. Is this normal? Was I just playing with the settings too quickly?

Do I have to wait a few minutes in between each action or should I be able to switch speeds, temp, flip to heat on the fly within seconds?

Thanks,

Jeff

[bobstock]

Jeff,

Micro Air Easy Start.... $300.00 Easy to install just 4 wires. I can run my 13.5 K BTU Dometic Heat Pump on a Honda 2000 . World of difference. I think this will be very helpful to you.

[BayouBiker]

You should be able to make adjustments, additions and subtractions to load within a few seconds of each other and not trip a breaker or overload the generator or its inverter. Near simultaneous load changes may occasionally cause what you describe, but there has to be an additional instability in your system. Describe the cabling between the generator and trailer, any grounding you may have and any other connectors and panels etc.

[Ken G]

Is your electric hot water heater on?

[GCinSC2]

You have a new 2020. IMHO as I see it this needs addressed by dealer. You’re under warrantee.

The respected micro air reduces the peak starting current that’s its job. Pretty sure once system starts it’s done. Micro air can answer definitely.

You could research power consumption (amps) of AC and microwave and convertor all running at the same time and see how consumption vs supply works out. Convertor amperage might be hardest time determine what’s actual due to its charging states, coast pull grunt. A fairly easy add on is AC volt meter. I have an analog meter that plugs into outlet. Pretty basic stuff but it will show you line voltage and when my AC water kicks in you can see voltage takes a hit. Power management but that’s later on.

[Buckless]

After your ac compressor starts it builds up head pressure. If you adjust controls too fast you may turn off and on compressor before head pressure has a chance to bleed down. The compressor can not restart under head pressure and may overload the generator. It is not good for compressor to continually restart under load.

[Bill M.]

If you do something that causes the compressor to cycle then yes, you are doing it wrong. So yes, if you turned the temperature setting up and caused the compressor to stop and then turned in immediately back down again you would get the problem you describe. Or any other sequence of switching that causes the compressor to cycle.

The Easy start will reduce the starting current of the AC but not the running current. You can probably run with a Honda 2200 without the Easy start. Just keep the thermostat on full cold to avoind the compressor cycling. I like having the easy anyway because it reduces the startup thump.

One should wait 2 min after a compressor stops to restart it. Not to do so can seriously damage the AC unit. The starting load is a lot higher on a quick cycle and you can fry the starting circuit. One think I like about my surge protector/EMS is that it has a built in delay of about 2.5 min on any start or restart. So a quick shutdown and restart from a lightning strike or more commonly somebody at the camp ground messing with the power will not hurt the AC.

I did not state that we run the WH on propane and the refrigerator on propane when running the AC on our 2000 generator. I turn off the converter most times. Our converter often is drawing 7 amps. We do not have an inverter. Our trailer is old and it has a switch that makes you choose between the AC and the microwave.

I have a 12 year old Honda 2000 so that is what I know. I have camped with people that run 2 of them and with people that run the 3000. Those people tend to be from the south and are used to running the AC a lot more than we use it. We camped for a number of years before we tried the AC on the generator, Now we use the AC on the gun a few days a year. I really got the generator for cold weather to keep the batteries charge up enough to use the propane heat. For years I thought it would not run the AC or would hurt the AC. Now I believe neither of those.

Out of all this I get the idea that your are not running a surge projector with a EMS built in. I think that for a new trailer like that you should get one and use it all the time. I camped for years without on but now know that I should have had one. We certainly hit a couple of low voltage campgrounds in eastern Canada. Just not enough incoming juice overall for a whole bunch of campers.

[JohnTF]

You may be not giving us all the correct info , some of that can be the lack of knowledge both of what you are doing and the things your working with .
Every thing could be ok , except for operator error - switching the AC around & back , the compressor & fan are two different motors , and the compressor is the largest draw .
A big - operator error issue is turning the controls around is short order - you should set the thermostat for changes ONLY , the possible issue is using the other control - shutting down the compressor and in short oder changing that ?
Any time a AC compressor is manually shut down --- it needs some time to drop the head pressure in the compressor , if the compressor is turned back on too soon / with high head pressure you are harming the unit .

For some numbers , a 13,500 btu AC unit needs 2750 watts to start [ well beyond any 2000 / 2200 watt generator ] then needs 1250 watts for running .
Then you use the microwave , not sure but that at least 800 watts more , and I would guess most likely 1500-1600 watts = so now we are looking at 2750 watts & 1600 watts = 4350 watts .

Let the thermostat control the AC , it will cycle the compressor as needed to keep the temp you set with the thermostat .

Remember when your using the AC - that any added load ---- ADDS , and in you case 4350 watts .

As for the generator , I will not even bother , the chineez are coming up with so many brands , so fast , I can't keep up - never heard of that brand , my 1st thought is it could be a " house-brand " one generator that the manufactures put what ever label on it the retailer wants , this happens with almost everything these days .

[Jeffr75]

Originally Posted by Bill M.

If you do something that causes the compressor to cycle then yes, you are doing it wrong. So yes, if you turned the temperature setting up and caused the compressor to stop and then turned in immediately back down again you would get the problem you describe. Or any other sequence of switching that causes the compressor to cycle.

The Easy start will reduce the starting current of the AC but not the running current. You can probably run with a Honda 2200 without the Easy start. Just keep the thermostat on full cold to avoind the compressor cycling. I like having the easy anyway because it reduces the startup thump.

One should wait 2 min after a compressor stops to restart it. Not to do so can seriously damage the AC unit. The starting load is a lot higher on a quick cycle and you can fry the starting circuit. One think I like about my surge protector/EMS is that it has a built in delay of about 2.5 min on any start or restart. So a quick shutdown and restart from a lightning strike or more commonly somebody at the camp ground messing with the power will not hurt the AC.

I did not state that we run the WH on propane and the refrigerator on propane when running the AC on our 2000 generator. I turn off the converter most times. Our converter often is drawing 7 amps. We do not have an inverter. Our trailer is old and it has a switch that makes you choose between the AC and the microwave.

I have a 12 year old Honda 2000 so that is what I know. I have camped with people that run 2 of them and with people that run the 3000. Those people tend to be from the south and are used to running the AC a lot more than we use it. We camped for a number of years before we tried the AC on the generator, Now we use the AC on the gun a few days a year. I really got the generator for cold weather to keep the batteries charge up enough to use the propane heat. For years I thought it would not run the AC or would hurt the AC. Now I believe neither of those.

Out of all this I get the idea that your are not running a surge projector with a EMS built in. I think that for a new trailer like that you should get one and use it all the time. I camped for years without on but now know that I should have had one. We certainly hit a couple of low voltage campgrounds in eastern Canada. Just not enough incoming juice overall for a whole bunch of campers.

Man I have a lot to learn! I jumped into the TT world overnight and I'm feeling bit discouraged. I will definitely follow up with the dealer, the big issue I had at delivery is the language, they were super nice but mostly French (I live in Quebec) and I only speak English. I'm not using a surge protector or EMS, but I think I will get these installed if it can be done as well as an easy start. It was also delivered during COVID shutdown in early May last month, so I got the quick version!

When I first turn on the AC its running ok and so is the generator. So to be clear, does lowering or raising the temperature too quickly make the compressor "cycle" which causes the overload? Because that is exactly when I have the issue. Like I mentioned, when I take time between adjustments and don't switch rapidly between high and low or use the thermostat dial to adjust temperature too quickly I seem to be ok. The best case scenario is that there is nothing wrong and I was just operating it incorrectly.

Thoughts?

[Jeffr75]

Originally Posted by JohnTF

You may be not giving us all the correct info , some of that can be the lack of knowledge both of what you are doing and the things your working with .
Every thing could be ok , except for operator error - switching the AC around & back , the compressor & fan are two different motors , and the compressor is the largest draw .
A big - operator error issue is turning the controls around is short order - you should set the thermostat for changes ONLY , the possible issue is using the other control - shutting down the compressor and in short oder changing that ?
Any time a AC compressor is manually shut down --- it needs some time to drop the head pressure in the compressor , if the compressor is turned back on too soon / with high head pressure you are harming the unit .

For some numbers , a 13,500 btu AC unit needs 2750 watts to start [ well beyond any 2000 / 2200 watt generator ] then needs 1250 watts for running .
Then you use the microwave , not sure but that at least 800 watts more , and I would guess most likely 1500-1600 watts = so now we are looking at 2750 watts & 1600 watts = 4350 watts .

Let the thermostat control the AC , it will cycle the compressor as needed to keep the temp you set with the thermostat .

Remember when your using the AC - that any added load ---- ADDS , and in you case 4350 watts .

As for the generator , I will not even bother , the chineez are coming up with so many brands , so fast , I can't keep up - never heard of that brand , my 1st thought is it could be a " house-brand " one generator that the manufactures put what ever label on it the retailer wants , this happens with almost everything these days .

You're right, I'm probably not giving you the right info because this is all new to me. The only AC and thermostat I have ever used is the one in my house. I really don't have a lot of knowledge with any of this stuff but I'm learning

Here's a picture of my controls



What do you mean by "turning controls in short order"?

For such an expensive trailer I feel like I have the most basic AC controls. I have one dial for the heat strip, AC speeds and the grey which is fan only. The other dial is my temp control/thermostat. Playing with either dial seems to cause the problem, unless of course I wait a few minutes (at least 1) before adjusting. Any quick back and forth overloads my generator. So is it me lol? Operator error?

[Buckless]

Yes an AC temp control or refrigerator control is not meant to be on , off, on, without a little time elapse between on and on again.
The head pressure will make it overload the generator.
Even if it were connected to the power grid the compressor can not start until the head pressure lowers enough, you will hear the overload click in your AC unit until pressure lowers enough for compressor to start.
Just turn it on and let it run