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LauraLafont

12V Ground Problem With Generator?

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Hello, first time poster.

I have a '95 Vogue Prima Vista with an Onan 8.0RV genset (8DKDFJ). Generator runs fine but this is a question about the controls or the chassis electrical system.

Here is the issue; If I have the RV plugged into the 120V 20A circuit at the storage facility, (or any other 120V circuit including 30A at camp site) and if I run any of the heavy power drawing electrical components like either of the roof AC units or the microwave, etc. the generator will think it has been turned on (or change over to a run condition with the generator engine not actually running.) 

The dedicated gauges light up, the run timer starts ticking away, and on the generator itself, the radiator fan runs and I believe the fuel solenoid gets energized. It will stay this way even if I turn off the AC or the microwave. The only what to stop the genset from "running" is to manually trip the DC control breaker on the genset.

Also, interestingly, I can hear a relay or the control breaker buzzing when the AC or the microwave are on. All other times everything seems to operate as normal.

This has not been too difficult to manage, except, it finally caught up to me. Today, I went to the storage unit to bring the RV home to pack for a 6 week trip, and the chassis battery was dead. House batteries are fine and still being charged by the shore 120V. (I remember a recent article in the FMCA magazine about a charger system that would manage both the chassis and house batteries. Something to look into once I get this issue resolved...).

But I remember the last time I was at the storage site, I was working on something unrelated and had the roof AC running for a while while I was working on the other project, (plumbing only, nothing electrical). I had to leave quickly and this generator condition may have been happening and I did not hear it as I left. I don't know.

Anyway, anyone have thoughts as to how to approach this? If I had to guess, I would think there is a ground issue somewhere but I would not have a clue where to start. Is this some kind of DC offset that is back EMFing into the system and fooling the generator into thinking it is on? 

One last clue. On the dash, there is a switch where I can monitor the voltage of either the chassis or the house batteries, if the generator DC control breaker is tripped, (off position) the gauge on the dash will only show the voltage for the house batteries and not the chassis. So, I try to keep the generator DC control breaker in the ON position so I can monitor both batteries. Also, if the generator is actually running on purpose, the off switch on the dash will not turn the unit off. I have to go to the bedroom and turn it off from the switch there.

Any thoughts would be appreciated.

Mike

Spring, TX

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Mike,

Welcome to the FMCA Forum!

Is there or has a Auto Gen Start feature been added to the generator? One needs to mindful that the Onan auto start has been subject to some issues.

 Also, interestingly, I can hear a relay or the control breaker buzzing when the AC or the microwave are on. All other times everything seems to operate as normal.

The dead batteries most likely due to the load, but check the condition of the batteries and that all the connections are clean and tight.

Rich.

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This does not have an auto start feature. But this has been an issue since I bought it 3 years ago. This buzzing sound happens at the generator control breaker when I am on a 120V shore power with a load. Not when the generator is on. It does not happen when plugged into a 220V 50A shore.

Another thought I have is; could this be related to the power transfer switch? something sticking or contacts not closing properly?

Mike

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Mike, yes it could be a power transfer switch or an issue in the J Box where the Generator power is connected to the coach wiring going to the transfer switch wiring in the area of the main power panel. Also check all the connections in the Main AC power panel behind the cover plate and the ground wiring between the coach and shore power circuit.

Things do come loose. See the image in this link. No power to the coach from the generator or shore power when checking any of the main power connections.

Rich.

Generator to coach J Box connection issue picture.pdf

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