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Bruce,
For what's it's worth... My 97 Marathon did not like the chassis battery charger running off the inverters. If I unplugged and forgot to turn off the 24V battery tender I installed, running off the block heater plug, all the lights in the bus would pulsate. Simple solution for me, make sure the block heater circuit breaker in the bedroom was turned off when unhooked from shore power.
Seems weird to me that they would wire an engine block heater circuit to run off the inverters....
Sure way to drain the batteries FAST!!
I agree Paul.. Maybe that's why there was no button on the dash for the AC block heater, only the circuit breaker in the bedroom panel.:rolleyes:
Apples and oranges.
The pulsating DC voltage should have nothing to do with what 120V loads are on the inverter. And I agree, the block heater among other things should not be running through an inverter. But if it is, that's just about as nonsensical as running a battery charger through inverters. That would be like lifting yourself off the ground by pulling up on your socks.
Thank you Jon for the careful review of the single alternator system. I am carefully considering what you have said and planning on attacking the problem this morning.
What I cannot understand is how I am going to be able to run my multimeter cables from the back of the bus to the Aux Air line hose outlet in the steer bay all the way up front to make the proper contacts??
Bruce said his dash lights were hunting up and down, similar to what mine did and that's why I made the comment, if it was even read.
I'm not making this crap up, it is what it is!
Paul,
In thinking more about the block heater running off the inverter, with the Marathon, that would be no big deal. It would run 1 cruiseair for 4+ hours and 2 cruiseairs for about 2 hours. Not much difference in the amp pull for the block heater and a cruiseair, my Liberty shows 14 amps for the AC block heater.
This should drive A-1 crazy.:p
The Block Heater AC Outlet in the back of the bus is a regular GFI outlet. There is a block heater with a plug that is not connected to the outlet, but rather wire tied next to it in case I wanted to plug it in. There is a breaker switch above thae dash for "Engine outlet". I keep it off unless I am using my Chassis battery charger that is also connected to the Engine AC outlet GFI receptacial.
I have not noticed the surging problem while having the charger on during engine operation, driving along.
What bothers me is that I can start a trip with absolutely no issues at all, but after about 3 hours began to experience a surge in the voltage meter, dash lights pulse etc.
I am being told that because the "House Batteries" are requesting a charge from the Engine alternator to keep the house batteries at a proper level to service the house draw.
If the Alternator or the regulator is not functioning correctly it appears that one or the other is creating an over voltage (which is tripping off the ABS computer my other problem) .
Marathon mostly installs single alternator conversions with a regulator Isolator and Vanner Load balancers.
Prevost said that it is one or possibly 2 of 3 problems:
1. Regulator is producing an over voltage and either needs to be turned down, or replaced, hopefully it is the regulator.
2. It could be a bad chassis battery, one bad apple causes a big draw.
3. A bad leg on the alternator, causing the other 2 to create more voltage to provide enough demand to the house batteries (isolator).
The final condition is the fact that the generator reduces the voltage dash meter from 29V. to 25V within 1 minute after starting the genset.
But when this happens the dash battery light comes on showing what I believe is an under voltage, go figure.
I am heading over now to start the inspection and testing process, will report, have a cheat sheet for testing provided by Prevost service manager.
If you have the single 270 amp 24v alternator, keep in mind that you have 2 equalizers, one for the chassis and another for the house. The house equalizer on mine was behind a panel on the forward bulkhead of the house battery bay.
Please consider turning OFF the battery charger when driving and see what happens. Tom's experience seems to indicate this can be a problem, and if you have that charger on while driving, then it's running off of the inverters, and Tom has indicate he experienced similar issues in his Marathon.
Some electronics does not like the modified square wave which comes out on an inverter.
It *may* be that when you turn on the genset, that now you're getting a better AC signal to the charger, and things settle down?
It certainly may not be the case, but it's trivial to isolate and rule this one out. Turn off the chassis charger, and drive it.
Ray