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Protagonist 08-12-2013 10:38 AM

Quote:

Originally Posted by Skater (Post 1339432)
So, if theirs is wired the same way, since the alt wasn't working, as the batteries depleted, eventually the voltage would get low enough that the gen would think it was being shut down, and shut down. Then it wouldn't start again because the voltage was low.

Hadn't considered that. If the generator isn't actually generating power, it can't self-power either, and so will draw power from the batteries to keep the spark plug sparking. Once the batteries get too low, the spark plug quits sparking, and the generator shuts down. By the time the batteries are too low to power the ignition coil, they're too low to power the electric starter motor, too.

But for the same thing to happen to a properly-working generator, that almost has to be keyed to the throttle control. A generator throttles up to increase RPMs as the load on the electrical system increases. Whatever mechanism controls the throttle probably relies upon battery power, so if there's not enough battery power, you can bog down the engine by overloading it; RPMs don't increase as they're supposed to with added load, which causes the generator to shut down.

Still grasping at straws here, but haven't reached the last straw yet.

Skater 08-12-2013 12:16 PM

The generator probably WAS generating power. It was generating 120 volts AC. But that doesn't do any good for the 12 volt DC side if the converter is off. Then the alt goes, and suddenly the only source of 12 volt DC power is the battery, which will run down without anything charging it.

reddog 08-13-2013 10:35 AM

Home and fixed
 
The rig made it home the rest of the trip without incident. The reman alternator solved the charging issue and is working like a champ. I think I posted it earlier, but that entire fix came in under 500 bucks, more than fair.
The genset issue did turn out to be slightly low oil. Went ahead and changed it and topped it off, no more issue.
So far, we really like the rig. The 2 couches fits our use better than a dinette set up and the rear kitchen is plenty big enough for us and with the rear door open, it makes for a nice view.
Thanks for all the help, comments and suggestions.

Lily&Me 08-13-2013 11:59 AM

reddog,you might look into one of the screen enclosures for your rear door, if you don't have one already.

Available from the Sprinter store, they are wonderful for parks, beaches, etc., where you have a beautiful view but insects keep your doors closed. :sad:


Maggie

wayneskid 08-13-2013 01:32 PM

Quote:

Originally Posted by Protagonist (Post 1339446)
......A generator throttles up to increase RPMs as the load on the electrical system increases. Whatever mechanism controls the throttle probably relies upon battery power, so if there's not enough battery power, you can bog down the engine by overloading it; RPMs don't increase as they're supposed to with added load, which causes the generator to shut down.

1. A generator "throttles up" to maintain RPMs not to increase them. The purpose of the governor is to maintain 60 Hz output under varying loads. This means that RPMs have to be controlled within a fairly narrow range, roughly 59-61 Hz.
2. The governor on these and most generators is mechanical and does not depend on battery power.

Protagonist 08-13-2013 02:14 PM

Quote:

Originally Posted by wayneskid (Post 1340023)
1. A generator "throttles up" to maintain RPMs not to increase them.

Thank you. As slow as I type, my fingers still go faster than my brain.


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