Roof AC Tripping Breaker When Driving

[Fonckadelic]

I have a Sunseeker class C and need some troubleshooting advise on the AC. When the RV is sitting, I can run the roof AC on the generator with no issues. However, when we are on the road and running the AC, noticed it will run for about 10 minutes then trip the breaker. The generator still runs, but can't tell if there is some inconsistency in it when were in motion.

Any idea where I should look for a cause? My thought is the generator may not put out consistent power when were in motion, so the draw from the AC is too much and trips breaker. The generator is a Generac...not sure if it was original. Previous owner said a shop told them this issue was due to a loose connection with the generator and was fixed. Not sure if that is correct...I didn't find any loose connections.

[SeaDog]

Welcome to the forum its a great place to get your questions answered. To me it sounds like the shop was on the right path but didn't follow thru by also checking/tightening the connections at the breaker distribution panel and AC. I would try that.

[Fonckadelic]

I'll definitely take a look at the connects at the breaker and the AC unit. Connections at the generator were tight. Makes sense that it may be loose wiring related since it only seems to happen when the RV is in motion.

[CrazyOldGuy]

(I see this is a couple of weeks old) You need to check the Running Amps on the AC at the breaker stopped and then check them again driving. I find it unusual that it trips moving. (Second, I'd turn off all the Breakers Except the AC and see if it sill trips.)

Have you added or changed anything about the time this started?

[Fonckadelic]

Thanks for the suggestion. The RV is in storage now so I'll have to check this when we get it back out. We have not changed anything since owning the RV in regard to AC, generator, or breakers. Seems that this was an issue from time to time with the previous owner.

The last trip we took I turned off the fridge, water heater and water pump just in case any of that drew power from the generator while moving. Still had the breaker trip on the AC after running for maybe 5-15 minutes. Hard to tell exactly when it occurs.

If the generator fluctuates in it's running speed slightly, would that temporarily cause a big enough drop in power for the AC to trip the breaker? And how amps should I expect if I measure at the breaker?

[CrazyOldGuy]

Originally Posted by Fonckadelic

Thanks for the suggestion. The RV is in storage now so I'll have to check this when we get it back out. We have not changed anything since owning the RV in regard to AC, generator, or breakers. Seems that this was an issue from time to time with the previous owner.

The last trip we took I turned off the fridge, water heater and water pump just in case any of that drew power from the generator while moving. Still had the breaker trip on the AC after running for maybe 5-15 minutes. Hard to tell exactly when it occurs.

If the generator fluctuates in it's running speed slightly, would that temporarily cause a big enough drop in power for the AC to trip the breaker? And how amps should I expect if I measure at the breaker?

You you've eliminated some things which is good. Yes, if the Voltage drops the Current (amps) Will Increase and can do damage! With out knowing the size of your AC the best answer would be Less than 15 Amps! Do you have a Digital Multi Meter or an Amp Gauge?

[TitanMike]

My first thought about what would cause something to cause the breaker to trip only when moving is that there is a loose connection or component somewhere in the A/C circuit. Something that can cause a short. If it were mine I'd start in the A/C, particularly in the compartment where there are two capacitors mounted. When I installed my Soft Start I noticed how it could be possible for a short should the small strap holding capacitors in place was loose and capacitors could move around.

If a wire connection is loose and ultimately resulting in a large voltage drop, enough to cause increased current draw, one might think it would also reveal itself by giving off a smell and showing burnt insulation. If at the generator it would also do the same when running microwave, toaster, etc.

Just thoughts.

[Fonckadelic]

Originally Posted by CrazyOldGuy

You you've eliminated some things which is good. Yes, if the Voltage drops the Current (amps) Will Increase and can do damage! With out knowing the size of your AC the best answer would be Less than 15 Amps! Do you have a Digital Multi Meter or an Amp Gauge?

Yes, I have a multi meter that I somewhat know how to use. When I get the RV back out of storage, I'll check the amps at the breaker when parked in the driveway, then again when moving.

[Fonckadelic]

Originally Posted by TitanMike

My first thought about what would cause something to cause the breaker to trip only when moving is that there is a loose connection or component somewhere in the A/C circuit. Something that can cause a short. If it were mine I'd start in the A/C, particularly in the compartment where there are two capacitors mounted. When I installed my Soft Start I noticed how it could be possible for a short should the small strap holding capacitors in place was loose and capacitors could move around.

If a wire connection is loose and ultimately resulting in a large voltage drop, enough to cause increased current draw, one might think it would also reveal itself by giving off a smell and showing burnt insulation. If at the generator it would also do the same when running microwave, toaster, etc.

Just thoughts.

The roof AC looks to be original from 2011...don't know size for sure. I think I know where to look for the capacitors, so I'll check there first, then maybe where the wiring comes into the breaker panel. I have a feeling my generator is fluctuating it's power output and possibly causing this, but again, hard to pinpoint generator sound when we are in motion and there is road noise and everything else going on. Noticed that the last time I ran the generator before putting into storage, it was blowing oil out the exhaust and leaking from the base pan.

[TitanMike]

Originally Posted by Fonckadelic

The roof AC looks to be original from 2011...don't know size for sure. I think I know where to look for the capacitors, so I'll check there first, then maybe where the wiring comes into the breaker panel. I have a feeling my generator is fluctuating it's power output and possibly causing this, but again, hard to pinpoint generator sound when we are in motion and there is road noise and everything else going on. Noticed that the last time I ran the generator before putting into storage, it was blowing oil out the exhaust and leaking from the base pan.

Not good signs


As for location of capacitors, take the cover off the roof mounted unit. Look for compressor unit. Usually on Curb Side, right behind the condenser. Directly behind the compressor there is a compartment covered by a sheet metal cover. A screw or two and off it comes.

If it's an OE, 2011 model it's possible the capacitors are ready for "preemptive" replacement.

[CrazyOldGuy]

A Capacitor is not going to tell you the size (of the AC). If your meter has Capacitance check the Cap (+/- 10%).

Look at the Compressor there will be numbers on it and you can identify the size but while you are there look for any frayed wires or something loose. It could possibly be a Bad Cap but normally when they fail that's it. With no/little AC experience I'd go back to watching the Amps. If it starts increasing and then trips or if it just spikes Up and trips the problems are different.

A loose wire will not necessary cause a short but it will cause the voltage to drop and the amperage will increase. Look for a wire or connection that has been HOT.

I am going to guess the AC amperage "should" be between 8 and 12 when running.