Generator stalls & main 12 volt circuit breaker trips

[DownTheAvenue]

Hopefully someone can add some ideas. Onan 2800 microlite starts but immediately stalls and the 12 volt main circuit breaker trips, so all 12 volt is dead. There is no load on the generator when this happens. Circuit breaker resets, all 12 volt restored until attempt to start generator and then the same things happen again. All 12 volt works on battery an when plugged into 120 volt.

Any ideas??????

[pianotuna]

Great Job!

joebedford wrote:
This is what the primary DC distribution looks like in my RV battery compartment.

[MEXICOWANDERER]

http://www.ebay.com.au/itm/80A-Car-Stereo-Audio-Circuit-Breaker-Amplifier-Amp-12V-24V-/321933991037

Try this for a main breaker. I have found they have 99% fewer problems over a 5 year span. Locate it several feet away from the battery positive post.

[DownTheAvenue]

Thank you everyone for your help. I am leaning towards defective main, resetting circuit breaker. I will post the solution if and when I have it!

[DrewE]

joebedford wrote:
This is what the primary DC distribution looks like in my RV battery compartment. The battery is connected to the bus bar on the bottom. The heavy DC loads (like front jacks) are connected to that bus through auto-reset breakers.

May I suggest replacing that plastic circuit breaker holder with this style available here:


The plastic ones have the very bad characteristic of insulating one terminal on the breaker, forcing the current to flow through the threads from the nut to the stud. This can be trouble-prone. The metal one allows the connectors on both terminals to properly seat against the shoulder of the stud on the breaker. I had a similar setup on my motorhome, and found some of the breakers were barely sound structurally (partly from age but I think partly from the heat/connection issues). The metal bracket is a bit wider and I think a hair taller; the spacing of the breakers is the same, but the mounting ears spread out a bit more.

[joebedford]

This is what the primary DC distribution looks like in my RV battery compartment. The battery is connected to the bus bar on the bottom. The heavy DC loads (like front jacks) are connected to that bus through auto-reset breakers.

[MEXICOWANDERER]

Battery power to be interrupted by an incoming charge would have to involve a DC transfer switch
A gen auto start has such protection but an RV? "All DC power is chopped. What does the chopping? A psychotic converter that has the ability to sever power can do it but newer converters are power supplies - battery chargers. Is there a master breaker inside the rig's fuse load center? Something that goes open circuit causing a general outage including generator control? Surely they wouldn't hide a trashcan grade sixty-nine-cent auto reset master breaker inside a fuse load center, would they?

[Matt_Colie]

I think YXM is on track, I saw this happening on a yawl a few years ago. The APU would start and promptly shut down and everything was dead.

It took some doing to find, but the final diagnosis was that the house bank was asking too much of the cold generator. Modern converter/charger/inverters can hit the AC supply hard when first fired up. We finally trapped the sequence:
1 - The generator (APU) would start (autostart in this case)
2 - The converter would grab the output and lug the poor APU down and at the same time is would pop the DC breaker at the system main and if it didn't it would pop the AC breaker on the APU. The the converter would pop the battery main breaker.
3 - It would be suddenly quiet and it took less than a second for this to happen.

We were able to get the owner going again by having him shut off the autostart and open the APU breaker. Then, fire the APU and let it get rolling unloaded. Close the APU breaker and cross fingers.
If it stayed on line great.
If no, disable the convert/charger/inverter monstrosity and get the APU stable - this gave the house bank time to recover from the starting load of the APU and then when the converter was enabled, it didn't pull the APU to its knees.

More fun on the water.

Matt

[DownTheAvenue]

MEXICOWANDERER wrote:
Try to insert an image into this thread showing the "12 Volt Circuit Breaker. Curiosity overwhelms me...

I have no idea where it is, I just know what happens.

[MEXICOWANDERER]

Try to insert an image into this thread showing the "12 Volt Circuit Breaker. Curiosity overwhelms me...

[DownTheAvenue]

wa8yxm wrote:
I can tell you why the generator stalls. but not why the breaker is breakering.

The generator uses 12 volt BATTERY/CONVERTER power for the fuel pump and for ignition control.. So if it looses the 12 volt feed due to the main breaker tripping, It's the same as pressing the OFF button. or turning off the ignition on your car.. It does not "Stall" it is "Shut Off".

But I have no idea why the breaker is breakering.. Possible converter issue. that is the only thing I can think of, is a converter issue.

This helps to explain why the generator quits. I assumed it stalled. It is in a class B van AKA "motorhome".
Thanks!

[wa8yxm]

I can tell you why the generator stalls. but not why the breaker is breakering.

The generator uses 12 volt BATTERY/CONVERTER power for the fuel pump and for ignition control.. So if it looses the 12 volt feed due to the main breaker tripping, It's the same as pressing the OFF button. or turning off the ignition on your car.. It does not "Stall" it is "Shut Off".

But I have no idea why the breaker is breakering.. Possible converter issue. that is the only thing I can think of, is a converter issue.

[beemerphile1]

Where exactly is this 12vdc breaker located?

[MrWizard]

is this a TRUCK camper or a TT with the generator option ?

the typical 12v thermal breaker auto reset on a TT is 40amps
if the charger/converter power is greater than that it will trip

if this is a class B or C
the generator might get starting power from the engine battery

[CA_Traveler]

Pull the shore cord and simply discnnect the 120V gen output toI isolate between 120V load vs gen/12V issue. What happens?