Generator only starts with engine running

weatherbear · 03-08-2021, 03:01 PM

I’ve run into a conundrum. Rig is a 2016 Axis 24.1. This started after driving over teeth-rattling washboard roads for several minutes. May or may not be related. Anyway, the short story is my generator only starts after my engine has been running for a minute or so. It continues to run like a champ as long as my engine is running. After shutting off the engine, the generator will continue to run for about 5 to 15 minutes before shutting down on its own. The time it runs on its own seems random. Any help greatly appreciated.

JamieGeek · 03-08-2021, 03:27 PM

Simple question: Is your use/store switch in "Use"?

weatherbear · 03-08-2021, 03:38 PM

Of course.

**16ACE27** · 03-08-2021, 03:46 PM

See this thread:

https://www.thorforums.com/forums/f8...ine-22493.html

Post # 22 was the resolution: 100 Amp DC breaker tripped. But the BIRD/BIM was connected to the downstream side of the 100 amp breaker, not the battery side.

USE/STORE Not Applicable

Basic Schematic:

Bob Denman · 03-08-2021, 04:34 PM

Check your battery connections to the coach batteries.
(you mentioned the bone-jarring ride...)

Trkyte@msn.com · 03-08-2021, 06:21 PM

Fuel tank above 1/4 ?

javelin · 03-08-2021, 08:32 PM

16ACE27 is correct; some coaches "probably" have the BIM wired to the gen/jacks side of the 100 amp breaker tied to the coach batteries. There are wiring variations out there.

So the alternator is charging the chassis battery when engine is running.....BIM closes in a few minutes to also try to charge coach batteries, but they are actually disconnected if the100 amp breaker has tripped open. When engine is shut off chassis battery charging stops and the BIM remains closed for a time keeping chassis battery connected to the gen micro controller. Then the BIM opens off the chassis battery connection a few minutes after (since no charging is detected)......and no 12vdc on the gen micro shuts the gen down. An evil scenario, depending on how the coach is wired. Find your 100 amp re-settable breaker and reset is the likely solution per 16ACE27.

weatherbear · 03-08-2021, 08:38 PM

Thank you everyone, tripped breaker that the battery tripped on a major bumpy road because it’s an inch away has been reset. Nice design there Thor! 😂

Bob Denman · 03-08-2021, 08:45 PM

Glad to see that you got it beat!

**16ACE27** · 03-08-2021, 09:08 PM

Yeah, the generator would be happy to continue to run when you take away 12 VDC to it except for one thing:

Gasoline!: No 12 VDC = no fuel pump = no run.

weberrg1152@att.net · 08-31-2023, 12:29 AM

My 2019 Thor Daybreak is the same. Generator won’t start unless engine is running. Is this how it’s supposed to work???

weberrg1152@att.net · 08-31-2023, 12:50 AM

Ok yes that makes sense since the generator runs on gasoline. And I imagine if I turn off the engine the generator will shut down after a few minutes.
First time I’ve owned a Motor coach with a generator. 🥳

TheGoodLife · 08-31-2023, 01:16 AM

Quote:

Originally Posted by weberrg1152@att.net

My 2019 Thor Daybreak is the same. Generator won’t start unless engine is running. Is this how it’s supposed to work???

No, absolutely not.

paulwadley · 08-31-2023, 01:53 AM

The generator is supposed to run on it's own since it is tapped into your motor home's fuel tank and attached to your battery. If it only runs while the engine is running, something is wrong with the way it is wired.

Paul

weberrg1152@att.net · 08-31-2023, 04:44 PM

Thanks Paul. I assume the 12V battery has to be fully charged and the battery disconnect switch in the on position. I will try it again !!

**16ACE27** · 08-31-2023, 04:54 PM

Quote:

Originally Posted by weberrg1152@att.net

Thanks Paul. I assume the 12V battery has to be fully charged and the battery disconnect switch in the on position. I will try it again !!

The generator needs 12 VDC from the house batteries to start and run. It can also get it from the engine alternator if the house/chassis battery disconnect is shut. But if 12 VDC goes away from the generator due to:
No house battery supply, and
No chassis battery supply, and
No converter supply:

The generator will shut down.

weberrg1152@att.net · 08-31-2023, 09:23 PM

Thank you I will try to start again & keep my fingers crossed!!!

Corc · 08-31-2023, 11:05 PM

The generator needs 12 volts to run, control, relays and fuel pump. Without 12 volts the ECM will shut down gen and generate a fault code.

Does it not turn over at all? Check DC voltage. If low, you have a bad connection or battery, staring engine boosts the voltage. If no voltage, bad relay or fuse in line.

weberrg1152@att.net · 09-01-2023, 05:58 PM

Ok I did a test and generator will start/ run when engine is running. But when I turn off engine the battery test says E and generator won’t start.
I conclude I need a new 12V battery. We have an extra marine/ RV battery to connect.

**16ACE27** · 09-01-2023, 06:09 PM

Quote:

Originally Posted by weberrg1152@att.net

Ok I did a test and generator will start/ run when engine is running. But when I turn off engine the battery test says E and generator won’t start.
I conclude I need a new 12V battery. We have an extra marine/ RV battery to connect.

Did you locate the 100 amp DC breaker from the house batteries to check its status? Have you put a voltmeter on the house batteries to check their status?

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