Shore power and generator

[myquantumLC27]

We just bought the Thor Quantum LC27, can you have the RV connected to shore power and run the generator at the same time?

[16ACE27]

Yes, once the generator comes online the Automatic Transfer Switch (ATS) will switch to the generator output and your SP connection will not be powering anything.

Best practice is to minimize AC load during the transfer so the Air Conditioner (A/C), water heater electric element and microwave should not be running when you do this or stop the generator.

[Beau388]

Originally Posted by myquantumLC27

We just bought the Thor Quantum LC27, can you have the RV connected to shore power and run the generator at the same time?

Yes. You have an automatic transfer switch just as shore power comes into the coach. When you start the generator, it will wait about a minute for the generator rpm to stabilize and then transfer power. This is a safety device to keep the power cord from becoming powered by the generator and causing a short. It is a good procedure to turn off any electric motors (A/C) when switching power sources.

[Bob Denman]

Yup! What they said...
If you take a look at your ATS: it may even specify that it prioritizes the generator as the "first source of power chosen".

[bevedfelker]

This has been discussed a few times on the forum. It befuddles my mind why when you are on shore power (and everything is powered by shore power) you want to run the generator.

[16ACE27]

Originally Posted by bevedfelker

This has been discussed a few times on the forum. It befuddles my mind why when you are on shore power (and everything is powered by shore power) you want to run the generator.

I can think of two normal valid reasons:

Time for that monthly generator maintenance/exercise.
Preparing to hit the road on a hot day that you know you will need the house A/C running.

Some people may mistakenly believe they can run both at the same time to provide more power to run more things, especially on a 30 amp coach. Hopefully, by asking the question they get that misconception corrected.

[Bob Denman]

Originally Posted by bevedfelker

This has been discussed a few times on the forum. It befuddles my mind why when you are on shore power (and everything is powered by shore power) you want to run the generator.

We just like to stretch the legs on that little diesel; every once in a while...

[The_Breeze]

Looked at a 2016 Jayco Greyhawk private sale once. Owner had it plugged up to a 30A in the side of his house. Did a preliminary once over, during which I tried to start the generator. No dice. Tried and tried.

Finally unplugged from the house and the gen fired right up. I guess the OP could try it to see? I didn't damage anything in the attempt.

[Jeg]

When I run the AC on generator power in my Thor ACE, everything is fine for about 30 min. or less, then the generator just quits running...so I start it back up and same thing again...any ideas where I might begin to troubleshoot the problem..?

[taylorbob1]

Originally Posted by Jeg

When I run the AC on generator power in my Thor ACE, everything is fine for about 30 min. or less, then the generator just quits running...so I start it back up and same thing again...any ideas where I might begin to troubleshoot the problem..?

- Gas tank must above 1/4
- check oil level on genny. Low oil will kill genny

Anybody got anything else to help Jeg?

[Jeg]

Thanks for the info...I will check oil in the generator...OK on fuel level...

[Beau388]

Originally Posted by The_Breeze

Looked at a 2016 Jayco Greyhawk private sale once. Owner had it plugged up to a 30A in the side of his house. Did a preliminary once over, during which I tried to start the generator. No dice. Tried and tried.

Finally unplugged from the house and the gen fired right up. I guess the OP could try it to see? I didn't damage anything in the attempt.

If the generator has an uncommanded shutdown it will always, well nearly always, show a error code. The code will be cleared if you successfully try and restart the generator.

[16ACE27]

Originally Posted by Jeg

When I run the AC on generator power in my Thor ACE, everything is fine for about 30 min. or less, then the generator just quits running...so I start it back up and same thing again...any ideas where I might begin to troubleshoot the problem..?

Does it do it every time? Or just while driving down the road?

There were overheating issues on some floorplans with the generator behind the front wheels - only happened when traveling though due to the generator sucking in hot tire and engine exhaust air.

[Wiley1]

Originally Posted by 16ACE27

Yes, once the generator comes online the Automatic Transfer Switch (ATS) will switch to the generator output and your SP connection will not be powering anything.

I'm trying to figure out why the ATS would give priority to the generator over shore power. It seems to me that shore power is "free" and the generator is not.

The other way around seems to make more sense. Suppose I leave my puppies in the camper and take the trolley into town. Its a hot day so, instead of opening windows, I leave the A/C on. When the shore power fails, maybe my Genset has autostart. But, when the shore power comes back on, wouldn't we want the Genset to turn itself off?

[The Gritz Carlton]

Originally Posted by 16ACE27

Does it do it every time? Or just while driving down the road?

There were overheating issues on some floorplans with the generator behind the front wheels - only happened when traveling though due to the generator sucking in hot tire and engine exhaust air.

While driving, this can also he caused by oil level not being perfect. Oil is circulating through engine with less in the pan. A slight tip around a curve or dip in road could trigger the low level shut down sensor.

[taylorbob1]

Originally Posted by Wiley1

I'm trying to figure out why the ATS would give priority to the generator over shore power. It seems to me that shore power is "free" and the generator is not.

The other way around seems to make more sense. Suppose I leave my puppies in the camper and take the trolley into town. Its a hot day so, instead of opening windows, I leave the A/C on. When the shore power fails, maybe my Genset has autostart. But, when the shore power comes back on, wouldn't we want the Genset to turn itself off?

If you’re dead-set on wiring it that way…
Talk to an electrician, you might be able to add the appropriate mods to make it work for you.

[Beau388]

Originally Posted by Wiley1

I'm trying to figure out why the ATS would give priority to the generator over shore power. It seems to me that shore power is "free" and the generator is not.

The other way around seems to make more sense. Suppose I leave my puppies in the camper and take the trolley into town. Its a hot day so, instead of opening windows, I leave the A/C on. When the shore power fails, maybe my Genset has autostart. But, when the shore power comes back on, wouldn't we want the Genset to turn itself off?

The ATS is a safety device not an accessory. It is there to prevent the shore line from becoming hot and back feeding power into the grid.

Back in the day, there were actually two 20 receptacles inside the coach, one for generator and one for shore power. There was a short 12 AWG cable that ran from the circuit breaker panel with a three prong male plug at the end. You manually selected generator or shore power. Home generators have the same ATS as a RV plus a load shedding panel. My 1968 UltraVan had the CB panel two receptacles and connecting cable in the hall closet - I remember it fondly.

Several companies make a device to shut off the generator if shore power is detected.

[Wiley1]

Originally Posted by Beau388

The ATS is a safety device not an accessory. It is there to prevent the shore line from becoming hot and back feeding power into the grid.
Back in the day, there were actually two 20 receptacles inside the coach, one for generator and one for shore power. There was a short 12 AWG cable that ran from the circuit breaker panel with a three prong male plug at the end. You manually selected generator or shore power. Home generators have the same ATS as a RV plus a load shedding panel. My 1968 UltraVan had the CB panel two receptacles and connecting cable in the hall closet - I remember it fondly.
Several companies make a device to shut off the generator if shore power is detected.

I absolutely understand what an ATS does. In the Navy we called it an ABT: automatic bus transfer. You can only have one source of AC power to your distribution panel. Having them both connected at the same time would be a disaster for a whole slew of reasons. In addition to being a safety device, it is also a convenience device. Because it is automatic, the user doesn't have to know when to pull down on a big switch handle.

My question is about priority. When both sources of power are available, why would the ATS choose to give priority to the generator over shore power? That seems backward to me and, so far, nobody here has been able to explain the reasoning for it.

If you have a Generac system at your house, which do you think is given priority? The utility power or the generator power? To me, an RV should be no different.

[Scubawise]

https://www.irv2.com/forums/f59/gene...ml#post4254783

[taylorbob1]

Originally Posted by Wiley1

I absolutely understand what an ATS does. In the Navy we called it an ABT: automatic bus transfer. You can only have one source of AC power to your distribution panel. Having them both connected at the same time would be a disaster for a whole slew of reasons. In addition to being a safety device, it is also a convenience device. Because it is automatic, the user doesn't have to know when to pull down on a big switch handle.

My question is about priority. When both sources of power are available, why would the ATS choose to give priority to the generator over shore power? That seems backward to me and, so far, nobody here has been able to explain the reasoning for it.

If you have a Generac system at your house, which do you think is given priority? The utility power or the generator power? To me, an RV should be no different.

Interesting thought.
Now you have me wondering…

Now we just need to figure out why RV manufacturers wire it with genny superior and plug-in inferior.