AC tripping generator

[Mdk0420]

Hey all. I seem to be having some AC issues unfortunately. I ran some diagnostics but I haven't been able to figure out the problem.

I'm using a Westinghouse igen4500df generator. This should be more than enough to start an AC however it's hit or miss. Sometimes it starts up, other times it just hums until the generator trips its overload protection.

I've tested the resistance of my compressor coils and they show no resistance. My capacitors are very close to their ratings (both within 2%). Motor starter is on the low end kf its 43-52 rating at 43.8 but shouldn't be causing the issue if it's within range.

On the generator side I've ran a few test and need to run a bit more because I forgot some data. But what I have so far is here:

A successful startup did a draw of 28-30 amps.

An unsuccessful startup maxes out the generator at 48 amps but the voltage was down to 95v during the heavy draw period. After about 5 seconds it trips the overload

The generators low voltage goes all the way down to 55v on initial heavy draw and comes back to 95v in under a second and back to 120v or so within 2 seconds except when it has the unsuccessful start. It doesn't get passed 95v and 48 amps.

I'm measuring from the start of the generator line using true rms equipment so these voltages are probably lower at the compressor.

The fan motor spins freely. I did not check the refrigerant. It does get nice and cold when on.

I do want to get a soft start but I'm still baffled that a 4500 watt generator can't start a single AC system. I run my 15k BTU AC uni in my shed no problem.

Any suggestions on what else to look at? Is this somehow normal for a unit without a soft start? Are Westinghouse generators just junk?

[Sophia11]

Using a Westinghouse igen4500df generator, the user has experienced inconsistent results when starting an AC unit. Sometimes it starts successfully, while other times it only hums before tripping the overload protection of the inverter generator. Testing the compressor coils shows no resistance, and the capacitors are within 2% of their ratings. The motor starter is within the specified range. On the generator side, successful startups draw around 28-30 amps, while unsuccessful attempts reach a maximum of 48 amps but experience low voltage (down to 95v) during the heavy draw period, leading to overload tripping. The low voltage drops to 55v during initial heavy draw but recovers quickly, except in unsuccessful starts. Measurements are taken using true rms equipment. The fan motor spins freely, and the refrigerant has not been checked. The user plans to get a soft start but is perplexed that a 4500 watt generator struggles to start a single AC system, even though a 15k BTU AC unit runs without issues in the shed. The user seeks suggestions on other possible causes and wonders if this is a common issue for units without a soft start or if Westinghouse generators are generally unreliable.

[Mdk0420]

I have not checked utility power yet. Whoever owned my house previous made a 250' 14 gauge wire run all the way to my garage. It too cannot start the AC because of the massive voltage drop (can't really do much other than run lights and lighter power tools but I have mostly cordless tools anyways). My garage can't run my 15k unit inside the garage either. But my generator can. That's a different system then what's in the RV. Must not draw as many amps because it doesn't trip my generator

[time2roll]

Is the A/C total amp draw within specification when running on utility power?

[Mdk0420]

JBarca wrote:

Mdk0420 wrote:

Thanks for the info. I have a feeling it's a combination of both issues. My generator might have a hard time handling hard spikes that max it out at the same time this compressor might just be very hungry for amps.

I think I will get a soft start because just about any AC I have or in the future would get, would be a nice addition to have just to make the components last longer if nothing else.

Do you recommend a soft start brand? I have been looking at then and don't know which ones would be good or not

If you make it to getting a soft start, the Micro Air brand is good from my dealings with them. This brand, https://www.microair.net/products/easystart-364-3-ton-single-phase-soft-starter-for-air-conditioners. Shop around as other retailers sell them, sometimes cheaper than buying direct.

I know there are other brands of soft starts out there, I cannot speak to the quality of them.

Also, ICON in Canada makes good AC shrouds that will fit your older Brisk Air AC unit. You stated it was brittle when you took it off. Amazon does sell its brand, sometimes cheaper than ICON directly. I have bought several of them when restoring older Sunlines. If you need help with the sizing, let me know. These folks, https://www.icondirect.com

John

Thanks for the recommendation. I'll look into this one and when I get one and install it I'll also update my testing.

[Mdk0420]

JBarca wrote:

Mdk0420 wrote:

CA Traveler wrote:
55V on startup? Sounds like the gen can't handle the surge. Even 95V is low.

What is the AC voltage and amps on shore power?

It seems to be a common problem with all generators due to the need to ramp up however from the tests I've seen the honda only drops to 95v for a few seconds. Then again the test I saw was with harbor freight testing us8ng a kill a watt meter and that thing is pretty slow and inaccurate.

To run my tests I plugged in the kill a watt meter first then a line splitter and used my clamp over the line splitter to get amp readings while using the ports on the line splitter to test voltages. The kill a watt meter helped me see wattage readings real time within some sort of accuracy. The amps and volts I did off my meter because the kill a watt doesn't hold min/max but also doesn't react quick enough to get the voltage drops. It was saying voltage drop was closer to 105v but i know that's not accurate when running the min setting on my meter I got a 55v reading. Testing shows that it ramps up to 95v almost instantly maybe a second or two before it gets back to 120v.

I know 95v is normal because of honda inverter tests I've seen. Those 2200i's can actually start ACs but my 4500w generator can't and it's kind of disappointing lol.

It's also weird that only sometimes it maxes out the generator almost like a motor locked up. Other times it starts up just fine.

Preload doesn't seem to help because it trips sometimes when the AC fan is still running but once the compressor kicks in it trips. It's very random and I can tell when it happens while outside because the generator will Rev all the way up for a few seconds and eventually trip

I just saw this response as I was typing when it came in.

OK, there is something else that may be going on. Your statement in blue turned up a few thoughts. Since you are running on a genny, you are boondocking off-grid, right?

Unless you or someone changed it, your 2003 Sunline is on the older American Enterprises power converter or the Centurion. What size battery bank do you have, and what guidelines do you follow when to plug in and charge the batteries? Those older power converters did not have a boost mode. The point is, what else is going in the camper that eats into 120 VAC power?

The fridge is going to take 325 watts 120 VAC unless you force it to gas mode only. The water heater will pull 1,400 watts if the AC elements is on, and the power converter, well, it's a wild card pending on how drawn down your battery is. Those 3 power draws can all be going on in the background and you not know it unless you force a test with them all off. For a test, turn the power converter breaker off, (Sunline used to put the power converter on the general purpose circuit) the fridge, and the water heater off, (yes your 2003 can have an electric element heater, the power switch is on the back of the heater itself, not on the tank panel. ) Then connect the battery, and it will run the 12 VDC to run the AC unit controls. If the genny works consistently, then other loads in the camper may be randomly adding up against you.

The clamp meter shows that there is no other major draw happening at the time of testing. My fridge is broken. Got a bunch kf yellow dust near the AC lines so I disconnected it last year. It should only be the compressor and the fan running.

Iirc I think draw before turning the AC unit on was around 20 watts on the kill a meter.

While camping I do run the fridge and stuff. The generator can work in those conditions as well. It's about the same randomness with or without the other loads. Maybe a little more frequently

[JBarca]

Mdk0420 wrote:

Thanks for the info. I have a feeling it's a combination of both issues. My generator might have a hard time handling hard spikes that max it out at the same time this compressor might just be very hungry for amps.

I think I will get a soft start because just about any AC I have or in the future would get, would be a nice addition to have just to make the components last longer if nothing else.

Do you recommend a soft start brand? I have been looking at then and don't know which ones would be good or not

If you make it to getting a soft start, the Micro Air brand is good from my dealings with them. This brand, https://www.microair.net/products/easystart-364-3-ton-single-phase-soft-starter-for-air-conditioners. Shop around as other retailers sell them, sometimes cheaper than buying direct.

I know there are other brands of soft starts out there, I cannot speak to the quality of them.

Also, ICON in Canada makes good AC shrouds that will fit your older Brisk Air AC unit. You stated it was brittle when you took it off. Amazon does sell its brand, sometimes cheaper than ICON directly. I have bought several of them when restoring older Sunlines. If you need help with the sizing, let me know. These folks, https://www.icondirect.com

John

[JBarca]

Mdk0420 wrote:

CA Traveler wrote:
55V on startup? Sounds like the gen can't handle the surge. Even 95V is low.

What is the AC voltage and amps on shore power?

It seems to be a common problem with all generators due to the need to ramp up however from the tests I've seen the honda only drops to 95v for a few seconds. Then again the test I saw was with harbor freight testing us8ng a kill a watt meter and that thing is pretty slow and inaccurate.

To run my tests I plugged in the kill a watt meter first then a line splitter and used my clamp over the line splitter to get amp readings while using the ports on the line splitter to test voltages. The kill a watt meter helped me see wattage readings real time within some sort of accuracy. The amps and volts I did off my meter because the kill a watt doesn't hold min/max but also doesn't react quick enough to get the voltage drops. It was saying voltage drop was closer to 105v but i know that's not accurate when running the min setting on my meter I got a 55v reading. Testing shows that it ramps up to 95v almost instantly maybe a second or two before it gets back to 120v.

I know 95v is normal because of honda inverter tests I've seen. Those 2200i's can actually start ACs but my 4500w generator can't and it's kind of disappointing lol.

It's also weird that only sometimes it maxes out the generator almost like a motor locked up. Other times it starts up just fine.

Preload doesn't seem to help because it trips sometimes when the AC fan is still running but once the compressor kicks in it trips. It's very random and I can tell when it happens while outside because the generator will Rev all the way up for a few seconds and eventually trip

I just saw this response as I was typing when it came in.

OK, there is something else that may be going on. Your statement in blue turned up a few thoughts. Since you are running on a genny, you are boondocking off-grid, right?

Unless you or someone changed it, your 2003 Sunline is on the older American Enterprises power converter or the Centurion. What size battery bank do you have, and what guidelines do you follow when to plug in and charge the batteries? Those older power converters did not have a boost mode. The point is, what else is going in the camper that eats into 120 VAC power?

The fridge is going to take 325 watts 120 VAC unless you force it to gas mode only. The water heater will pull 1,400 watts if the AC elements is on, and the power converter, well, it's a wild card pending on how drawn down your battery is. Those 3 power draws can all be going on in the background and you not know it unless you force a test with them all off. For a test, turn the power converter breaker off, (Sunline used to put the power converter on the general purpose circuit) the fridge, and the water heater off, (yes your 2003 can have an electric element heater, the power switch is on the back of the heater itself, not on the tank panel. ) Then connect the battery, and it will run the 12 VDC to run the AC unit controls. If the genny works consistently, then other loads in the camper may be randomly adding up against you.

[Mdk0420]

Thanks for the info. I have a feeling it's a combination of both issues. My generator might have a hard time handling hard spikes that max it out at the same time this compressor might just be very hungry for amps.

I think I will get a soft start because just about any AC I have or in the future would get, would be a nice addition to have just to make the components last longer if nothing else.

Do you recommend a soft start brand? I have been looking at then and don't know which ones would be good or not

[JBarca]

Mdk0420 wrote:


It is a ducted system. Do these AC units just happen to draw a ton of current when starting?

It's always been hit or miss since I got the generator. I would say it starts about 90% of the time unless I purposely short cycle it then I can pretty consistently trip it.

I did test both the motor starting Capacity and the main capacitor and they are within spec. I tested the coils as well to make sure there aren't any resistances in the coils and all seems good. The unit does work most or the time after all, and it is cold. It's just unreliable.

The older, and even the newer, RV AC units from Dometic and Coleman Mach do have a high spike of inrush current when the compressor starts. As I showed, 37 amps inrush on a Brisk Air 13.5 K BTU roof unit is common from what I have found. Again, assuming you are in the 120 volt range. My Fluke amp probe has a peak feature, not sure what meter you have to grab that peak spike, your reported numbers were lower. When mine is in constant scan mode I can't see that high spike the display is flashing so quickly.

Since you have the ducted system, you can try this to see if it helps your genny handle the spike better. On the AC T stat, select the fan to be "on" in place of "auto". This will turn the fan on all the time. Then turn the T stat to cool and set your temp. The compressor will cycle on and off with the fan running all the time. The intent of this test/trick is to lower the inrush combo of both the fan and the compressor at the same time.

If that helps make your genny run OK, then well, it helps tell a soft start can help compensate for your gennys inrush spike problem. It may be, your brand of genny is more sensitive to a high spike than others. The soft start on mine took a high 37 amps down to 18 amps. It is just that the soft start does cost a good bit, but still less than a new AC unit nowadays.

OR, if the fan is on all the time when running the AC helps solve it, you can run it that way when on genny power. The only issue is the fan noise all the time. We like the AC to shut down totally when the T stat setpoint is satisfied to not hear the fan noise. Some folks like the white noise of the fan, and some can't stand it. Sort of a personal preference.

There is a cleaning procedure of the inside and outside coil that can help lower the fan power which "might" help you. That said, it will only lower the fan an amp or two, but it will lower a small bit of the combo inrush current. If this interests you, let me know I can link you to it, I have a post on the Sunline Forum showing how to do this. If yours has not been cleaned, well ever, it is good to do the cleaning anyway.

The new AC unit motors are a little more efficient. When the time comes to get a new AC unit, the Coleman Mach brand has more offerings for lower power use. The new Dometic AC's do not offer as many choices. Both brands will require the air box and the T stat control to be changed.

Hope this helps,

John

[Mdk0420]

CA Traveler wrote:
55V on startup? Sounds like the gen can't handle the surge. Even 95V is low.

What is the AC voltage and amps on shore power?

It seems to be a common problem with all generators due to the need to ramp up however from the tests I've seen the honda only drops to 95v for a few seconds. Then again the test I saw was with harbor freight testing us8ng a kill a watt meter and that thing is pretty slow and inaccurate.

To run my tests I plugged in the kill a watt meter first then a line splitter and used my clamp over the line splitter to get amp readings while using the ports on the line splitter to test voltages. The kill a watt meter helped me see wattage readings real time within some sort of accuracy. The amps and volts I did off my meter because the kill a watt doesn't hold min/max but also doesn't react quick enough to get the voltage drops. It was saying voltage drop was closer to 105v but i know that's not accurate when running the min setting on my meter I got a 55v reading. Testing shows that it ramps up to 95v almost instantly maybe a second or two before it gets back to 120v.

I know 95v is normal because of honda inverter tests I've seen. Those 2200i's can actually start ACs but my 4500w generator can't and it's kind of disappointing lol.

It's also weird that only sometimes it maxes out the generator almost like a motor locked up. Other times it starts up just fine.

Preload doesn't seem to help because it trips sometimes when the AC fan is still running but once the compressor kicks in it trips. It's very random and I can tell when it happens while outside because the generator will Rev all the way up for a few seconds and eventually trip

[Mdk0420]

JBarca wrote:


Hi,

I am very familiar with the Sunline campers. A 2003 Sunline, 27 ft would most likely have 13.5K btu AC on it unless someone upgraded it.

See this post where I did some amp testing on my Sunline. Before on the 13.5 K btu unit and then on the 15 K btu unit with the soft start.

***Link Removed***

On my coil cleaned 13.5K btu unit, with the power converter running on a charged battery, no other 120 VAC on in the camper, but the AC fan was on before the compressor kicked on, and I got 37 amps in rush.

As I was typing this, something dawned on me, what model is your Sunline? Or, more importantly, do you have a ducted system, meaning multiple ceiling ducts, OR do you have no ducts and all the cold air comes out of the center area of the AC unit inside? (a non-ducted AC) The control systems are different for the ducted and non-ducted.

Hmm, have you ever run the AC on your genny successfully in the past?

I can see maybe 2 things giving you an issue if you are on the ducted AC system.

Your compressor starting capacitors may be weak on the older motor, (there should be 2 caps in your AC junction box up the roof if it is the original)

Your genny does not have much surge spike forgiveness. Again this comes back to, did that genny ever run the AC unit well or are you just trying it now for the first time?

Dirty coils on the AC will pull a little more current, but not that should stop your genny from working.

Hope this helps

John

It is a ducted system. Do these AC units just happen to draw a ton of current when starting?

It's always been hit or miss since I got the generator. I would say it starts about 90% of the time unless I purposely short cycle it then I can pretty consistently trip it.

I did test both the motor starting Capacity and the main capacitor and they are within spec. I tested the coils as well to make sure there aren't any resistances in the coils and all seems good. The unit does work most or the time after all, and it is cold. It's just unreliable.

[Grit_dog]

The first thing to do, no magic or skill required is verify whether it’s the generator or the AC that is the problem.
Plug it into shore power. Even a good solid 15A residential outlet with no other loads on the circuit “should” get the AC going. 20A for sure will.

Could very well be a bad genny. My few experiences with cheap generators have been hit n miss. Few years ago we bought a bunch of 2k Yamaha knockoffs at Costco for running flagger stations.
My engineer at the time tried using one to run the AC in his old camper. Tried 3 different units , all new or almost new. 2 of the 3 would overload and not start the AC. But a new actual Yami 2k and an old beat up Honda 2k worked consistently.

[pianotuna]

try adding an electrical load before starting the air conditioner.

[CA_Traveler]

55V on startup? Sounds like the gen can't handle the surge. Even 95V is low.

What is the AC voltage and amps on shore power?

[BarneyS]

A SoftStart would probably solve your problem.
Barney