Genset won't take load

[Cinequip]

Yesterday in 100 degree weather i started the generator, but when it took the load the engine slowed and then died. Tried it again on both dash switch and panel -same result. I killed all the house breakers and was able to get it started. Then turned on one breaker at a time. Was able to run both AC and microwave OK.

It's HOT in the xantrex cab. Thinking about killing the breaker while driving so it doesn't overheat.

Also turning off battery charger during the day on shore power due to batt temp of 112! Charging in the morning.

Fun times!

[Wil Rathke]

Our generator will not continue to run or "take the load" when the engine is running. A work around solution is to disable the Xantrax charger from the control panel and then the generator will run while driving. Sometimes the gen will run if it is started before the engine is started. I don't know if your condition is similar to mine but it sounds familiar. I suggest you check the Onan fault code per the directions in the manual. If it is a code 27 which is "lost sync", it could be the same as my problem.

[dgerstel]

Scott,

Was this after the dash air had been running for a while or a day or so later? Were both AC's already calling for cool on the thermostat? The thermostat is controlled by 12 volts, so if it is set to cool before the 120 volt power is applied, it will call for both AC's to run right away. The proper start up is: Start one AC fan, pause, start that AC compressor. Then after a pause do the same for the next AC. If the thermostat is calling for both AC's when the 120 is applied, there will be a very heavy load applied by 2 fan motors and 2 compressors starting at once.

Is the Xantrex cabinet you are referring to, the compartment in the service bay?

[jerry davis]

Our generator died every time we applied a load. Turned out to be loose wires at the box where the generator cables attach to the coach. Since then I have checked all our connections and found many poorly tightened terminals.

[powerboatr]

ours will trip the breakers if you do not shed all loads prior to the switch over.
once its the primary source of power i power up one a/c, wait till its going and then turn on the rear a/c, then it all works perfect, engine on or not

[Cinequip]

Thanks for the good feedback.

Wil, i think you may be on to something with the gen start with coach engine running. When I was filling up water in Zion earlier, I had the engine off and the genset started up perfectly.

Dale, considering above stmt, yes I had both AC units off. Only load would have been microwave electronics, D-TV receivers, refer AC, surge unit, and Xantrex. Not a huge in-rush load. Interesting that killing all the 120v breakers in the hall panel allowed the startup - even with engine running. Wife's picking up two clip on fans at Walmart. Intend to mount one near Xantrex unit in utility compartment and other in battery compartment, both with doors open.

I'll check those genset wire connections - found several loose ones in other parts of coach so far.



105 in Zion right now. Batteries at 103 with charger off.

[Wil Rathke]

Scott, you might want to search the following forum topic.
Generator Shut-off--Fault code 27
Good luck.

[Cinequip]

Dale,

oh yeah, dash AC had been running all day when we experienced the genset startup failure.

[powerboatr]

Quote:

Originally Posted by Cinequip Thanks for the good feedback. Wil, i think you may be on to something with the gen start with coach engine running. When I was filling up water in Zion earlier, I had the engine off and the genset started up perfectly. Dale, considering above stmt, yes I had both AC units off. Only load would have been microwave electronics, D-TV receivers, refer AC, surge unit, and Xantrex. Not a huge in-rush load. Interesting that killing all the 120v breakers in the hall panel allowed the startup - even with engine running. Wife's picking up two clip on fans at Walmart. Intend to mount one near Xantrex unit in utility compartment and other in battery compartment, both with doors open. I'll check those genset wire connections - found several loose ones in other parts of coach so far. 105 in Zion right now. Batteries at 103 with charger off.

OW that's like it was here for the past few weeks, my battery temps were way over 105, BTS read 135 and 140 on the transformer, then we got four new batteries and all is well.

loose wires really sound like a strong culprit
i would also look at the transfer switch lugs, two of mine were found with edges broken off, when the surgeguard was put in. so the wires were sort of just holding themselves in
and for grins
when the engine is running it charges both sets of batteries
and I think somewhere in the magnum circuitry there is an isolator or something, because if the genny is running the battery charger/inverter picks up the charge load for both sets of batteries, i haven't figured out how or why, and my instruments panel tells me the engine is charging 13.7 ish
keep us posted

[dgerstel]

Scott,

Make sure that the water from the dash AC condenser is not dripping on the generator. On my '02, water got into the generators circuit breaker, causing the generator to act as yours is.

[takepride]

Scott:

As most have mentioned, it sounds like there is a problem with connections (or water in connection, as per Dale). If properly working, you can start the genset at any time and start the ACs at any time, irregardless of the engine running, order of starting, dash AC, breaker settings (except to ACs, of course) or charger status.

When starting the ACs, the front unit's fan will come on after as much as two minutes, followed by the compressor a bit later, then the rear unit's fan will come on, followed by the compressor.

I often leave the ACs "queued up" to start when I'm driving. If the dash AC isn't cooling enough, I hit the genset starter and the rooftop units kick in.

If your inverter is overheating, it would shutdown and let you know. I'd also check the batteries' condition and charging (as per powerboatr) to see if they are overheating during charging, as bad batteries are wont to do.

Another thought... check to make sure your "power share" setting is set to 50 amps on the inverter control panel. Maybe it's trying to "share" some minimal amount.

[Birddog Pilot]

I've had and continue to have, about 90% of the time, the same problem. After a normal start sequence the generator runs fine for the 30-40 second period prior to picking up the electrical load. At that point you can hear the relay/s actuate and the LED's on the convection over will start to flash indicating that AC power is in the process of being applied -- then the generator will promptly shut down. It will do this over and over unless there is an electrical load, possibly a significant load, present to be applied to the generator. In that case the generator will pick up the load and operate normally. I usually have one of the air conditioners selected so that the generator will immediately pick up the load of the fan; this always works. Then again, 90% of the time the generator will continue to run after the air conditioning unit has been turned off. But..., there are times when as soon as I turn off the AC electrical power load the generator will quit.

A year ago Cummins Cal Pacific, El Cajon, CA had spent a week troubleshooting the problem, $$$$ for me, and never could resolve the issue. They checked the Surge Guard, transfer switches, all possible electrical connections. The inverter program for "power share" was also reviewed with various settings, no luck. They also tried a temporary replacementof the "generator "brain." Nothing worked; so that's why I have to use this work-around method. I don't like it that it doesn't work as advertised; but no one seems to be able to fix it, so I live with it.

[Old Scout]

There is a Onan (Cummins) service bulletin out on Onan/Xantrex interface issues--ie Code 27. Some Cummins techs know about, Xantrex blames Onan. I have heard the "latest" Xantrex firmware upgrade will fix this--have been unable to confirm with Xantrex: 1) there is an upgrade or 2) that it will fix "Code 27."

[Cinequip]

Thanks for the continued info. I tried the "leave the AC stat queued for cool" trick today, after the genset again failed to take the load. Surprise! With the AC set to come on immediately upon 120v, the generator took the load just fine. Very strange. So I guess I will pursue the code 27 software upgrade idea.

With regard to setting Power Share to 50A, my Xantrex does not offer that choice. Power share choices top out at 30A*. Not sure what the "*" means. Do other Alpine owners have a 50A power share option??