Remote/Built in Genny Question

[Fisherman]

When you have a 5th or trailer with a built in genny, is there a very short delay between start up and when you actually get power or does the converter not "kick in" until it gets the full 120V AC. Reason I'm asking is that some genny mfgr's recommend plugging into the genny after it's running and not try to start or stop with the main cord already plugged in. Same idea when adding a remote start to a smaller genny, more or less giving it a load before its fully up to speed. Seems one of my son's friends leaves his plugged in and the converter has decided to let the smoke genie escape. Thanks.

[deltabravo]

Fisherman wrote:
When you have a 5th or trailer with a built in genny, is there a very short delay between start up and when you actually get power or does the converter not "kick in" until it gets the full 120V AC.

Yes, there's always a delay - if the electrical system is built correctly and uses a "transfer switch" that selects between shore and generator power.

There's a timing circuit built in to the transfer switch.


Some low end RVs (motorhomes in the Cruise America rental fleets) don't use a transfer switch. You take the shower power cord and plug it in to a 30 amp outlet which is the power outlet hardwired to the generator.

[Fisherman]

Great thanks for the help, I'll pass the info on to my son.

[gotsmart]

In the cubby that stores my shore power cable there is a receptacle from the MQ 4000.

I plug the shore power cable into the receptacle, then go inside and start the generator.
I don't wait for it to be running before I plug in the shore cable. Never had a problem with the appliances.

BTW, the Onan MicroQuiet 4000 is misnamed. There is nothing small and nothing quiet about it. 😄

[Fisherman]

2oldman wrote:
I'm not sure of what importance the converter would be in this. You mean there's a slight delay in getting 12v?

No, not so much in getting 12V DC, but stressing the system while the genny is in start up mode or shut down for a couple seconds as the 120 V AC ramps up. As others have noted there may be a "safety built" which will shut down the converter if the voltage is too low.

[DrewE]

If there's an automatic transfers switch, the ATS has a delay between when the generator starts and when it switches over to generator power, typically somewhere in the vicinity of 30 seconds.

If your setup does not have an automatic transfer switch, but instead you have to plug the shore power cable into a socket connected to the generator, then the power would come up immediately as the generator is getting up to speed. Similarly for external generators, although some (most? all?) inverter generators may have a time delay of some sort before they output power at all.

It is generally the best practice to not start a generator under load, particularly a traditional fixed-speed generator, as it is hard on the engine and the voltage regulator. Inverter generators might have a delayed turn-on when starting up built into the inverter control electronics--I'm not sure on that.

As to the converter producing output, some do have low-voltage cutoff circuits that stop the output if the input voltage is too low. Modern converters are based around switching power supplies, which are by nature pretty insensitive to variations in the input power; I would not generally expect decent designs to be damaged by momentary low-voltage operation. That doesn't mean it's a good practice, of course.

[2oldman]

I'm not sure of what importance the converter would be in this. You mean there's a slight delay in getting 12v?

[enblethen]

Transfer switch could have a 15-20 second delay, if equipped.