Power Equipment Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
I have a Briggs & Stratton Q6500 generator. It’s about a year old but I’ve only used it twice. Both times were dry camping and it’s having the same issue. It will run normal, indicating a 50% load when I hook up my camper and the a/c kicks on. After a few minutes it revs up and overloads, tripping the system and cutting power. The first time I thought it may be a camper issue, but I had everything checked out and it doesn’t seem to be the issue. I’m only putting about 3,000 watts through it.

Any help would be appreciated!
 

·
Registered
Joined
·
267 Posts
Is that 3000W as 110V, or 220V? If it's all on a single 110V leg, you may well be overloading one of the 2 legs. A 6500W generator is 3250W on each 110V leg. If it's spread across 220V, that should help.

If you have a suitable meter, you might be able to monitor the draw as this happens, to better understand what you're drawing, vs what the generator is rated for.

And remember that a compressor will briefly draw a lot of extra current as it starts (roughly double the running current). This can apparently be worse when the compressor has shut off once (reached the target temperature), then goes to start again with pressure already on the system.
 

·
Registered
Joined
·
2 Posts
Discussion Starter #3
To be honest I’m not quite sure. It’s plugged into the 30amp spot on the generator so I’m sure it’s spread out? As far as spiking when it starts up, it is getting past the original start up. It’s running for a couple of minutes and the A/C unit never cuts off until the generator surges.
 

·
Registered
Joined
·
267 Posts
I hadn't looked it up earlier, but I see now that it's a 5000W continuous, 6500W-peak inverter generator. The 30A outlet is 110V and 220V (or 120V and 240V, in the manual). So the AC could be 110V, or 220V.

The AC is putting out cool air, so the compressor is definitely running, etc? Have you turned off/unplugged/etc any other loads in the camper? Inverter generators will change speed based on their load. It suddenly revving up and overloading may simply be an indication that something else has turned on, and overloaded the generator. A fridge compressor, or something else in the AC unit, etc. Is the compressor turning off after a few minutes, then turning on again as the generator overloads? A compressor re-start will be tougher than the initial startup. Setting the thermostat really cold is a way to help ensure the compressor is running continuously, for testing.

What if you set the generator to always run the engine at full speed, rather than reducing the speed based on the engine load? If a brief sudden load hits, having an inverter generator already at full speed can help it handle a big load that would overcome the generator if the engine was turning slowly. The load still needs to be within the rating of the generator, of course. But if the engine is turning slowly, and a big load hits, the output voltage will sag , while the generator is trying to speed up the engine. This can be tough on the item you're powering, and can cause the system to overload (the lower voltage can cause the device to try and draw more current).

What size AC? One of the 13,500 BTU ones? From my simple understanding, that kind should *probably* be OK here, but if it's 110V, not 220V, that could make it tougher. I have a Honda EU2000i (1600W continuous, 2000W peak), and I've ready that one of those will not run a 13,500 BTU AC, but 2 in parallel usually will. But in parallel, that's providing 3200W continuous, 4000W peak, on 110V. Yours can provide 2500W continuous, 3250W peak, on a single leg of 110V.

So far are all your tests the "same"? Camper AC running on the generator? I'd want to isolate the two, to understand if the generator will overload on other things too, or if it's only related to the AC. Run some other big load on the generator, at home if you need to. A space heater or hair dryer will often draw around 1500W, and can put a pretty significant load on a generator.

What happens if you load up one leg of the generator to nearly 20A, 2400W? That's the rating of the normal-looking outlets, and basically the rating of the 30A plug (20.8A per leg). Let it run like that for a while, and see if the generator suddenly overloads. If it's OK, move the load to the other outlet and test again. If that's OK too, I'd try to load up both outlets to get the overall generator load to approach 5000W, and see how it does.
 

·
Registered
Joined
·
1 Posts
Could be the the converter/charger used to keep your onboard battery charged.


They can easily draw 15+ amps when they cycle on.


Best thing to do is make sure you start with a fully charged RV battery. (and don't rely on your tow vehicle to charge the battery)



-RF
 

·
Registered
Joined
·
42 Posts
I know this is late, but the problem you're having is that the RV's are all 120v systems. That means your AC is a 120v.

The way the Q6500 is setup, it can only provide 2500 watts continuous on 120v. Sure it can surge to 3250, but your AC, without a soft start, probably wants more.

You would have been better off getting a generator rated at say 4500 watts with a 30amp RV outlet. Then you would have had access to 4500 watts on a 120v RV system.
 

·
Registered
Joined
·
519 Posts
yup on the soft start
see this page for a good one
scroll down to the 364 microair that is the good soft start for rv unit!
they can also be used on smaller window air units as well.
they let the 13K-15k btu units compressor start on smaller single 2200i honda generators.

not sure why the mfg of the camper ac units do not use these from the factory??
dometic and coleman sure are missing the boat for sure..
or just make all of the rv ac units inverter ac units... ramp up slow compressors, adjust to the temperature
and run lower head pressures for lower current draw...

look at the ac units in the Toyota cars these days... low head pressure, high flow.
better heat exchange, and last a long time! and in traffic I think there are cooler temps inside the car.

some of the new refridge units use the tech of freewheeling the gas in the compressor till the rpm is up to speed.
then closing the Freon or refringent valves to let the compression start.
cool idea!!
 
1 - 7 of 7 Posts
Top