AC/Generator/Converter

[Charlessyverson]

I have a 23B, a 13,500 AC, and a Champion 3100. The AC has been overloading the generator at elevation 8,000 ft, and I wanted to know if there is a way to shut off all drain other than the AC to see if it will run. Is there a way to shut the converter off? I understand that it typically has a load all the time. Any other suggestions for reducing any "hidden" watt usage?

Thanks everyone for the replies!

[mike837go]

The converter is not much of a 110V load, but you can see by switching off the circuit breaker. Remember all of your 12VDC load will be on the battery while that breaker is off. When you don't need the A/C, switch the converter on and keep the genset running for another couple of hours to recharge the battery.


Usually the microwave, fridge on 110 or the electric water heater are bigger loads. Make sure those are not loading your genset before going after the converter.

[Charlessyverson]

Ok see if this makes sense. The AC seems to start ok, but if I turn the temp warmer and then turn it colder, it will overload the generator. It seems the AC is working ok but is not as cold as I would expect. Would it be harder for AC compressor to start up again after it has been running?

[mike837go]

Originally Posted by Charlessyverson

Ok see if this makes sense. The AC seems to start ok, but if I turn the temp warmer and then turn it colder, it will overload the generator. It seems the AC is working ok but is not as cold as I would expect. Would it be harder for AC compressor to start up again after it has been running?

Unquestionably YES!

If the compressor has cycled out for more than about 3 minutes, it will be starting against zero pressure differential.

Turn the compressor off (move thermostat to warmer) and then almost immediately turn it cold again, the compressor is trying to start against full pressure. BAD! Overload! Non-spinning motor.

A properly designed A/C unit will trip a thermal overload and then reset after a few minutes. Hopefully, working normally afterwards.

And yes, the genset will be overloaded while the compressor motor is locked and before the A/C's thermal overload trips.

[frieed]

Exactly why I bought a Yamaha EF3000iSEB with battery powered boost.
3500W for 10 seconds to get that compressor spinning. Worked flawlessly at 8000' just last weekend.

[mike837go]

Originally Posted by frieed

Exactly why I bought a Yamaha EF3000iSEB with battery powered boost.
3500W for 10 seconds to get that compressor spinning. Worked flawlessly at 8000' just last weekend.

3500W or 35,000W won't make any difference when an A/C or refrigerator compressor attempts to start against full head pressure.

BUZZZ! <click>

3 minutes later the compressor starts.

If you leave the thermostat alone. Or make only 1* adjustments at least 10 minutes apart. Then the system will operate as effectively as possible under the current conditions.

[frieed]

My comment was for the OP, not for you Mike837go, sorry about the confusion.

Long version, Normally aspirated gensets lose HP at elevation just like any other engine.
At 8000' you're down about 24% capacity and your Champion generator doesn't have enough headroom left to cover the full starting current of the A/C (not against full head pressure) . If you can cover the startup current long enough to get the compressor running, then you are usually ok on the run power.
One possible help is to get a hard-start kit for the A/C that replaces the starting capacitors with larger ones to help supply more current on startup.

-Eric