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Generator not starting without coach engine


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This may be long but all is needed.

I have an Onan 5500, Mod. HDKA-2733B in an 03 Neptune, 300ISB Cummins Diesel.

When going to exercise the unit, Genset, it would prime but not start using the controls in the cab or on the unit.  Occasionally it would turn over a couple of times but not start.

Fuel level is 7/8 of a tank, same action with breakers on or off on the unit, Fault code is 1.  There is no second code.  Before each attempt in a new setup the Fault Code was reset.

Next oil level was made into the center of the indicators, coolant level was checked and full.  Air filter was clean and not blocked.

Starting trials were repeated and the same results with the same Fault Code of 1.

Next Onan was tried with motorhome running and it started and runs well until the motorhome was stopped then in 15 seconds the genset quit.  This happen several times until dark and we stopped testing..

Two days later I tried again with motorhome running and it would continue to run until I shut it off.  The Genset would not restart without motorhome running.  This scenario was repeated with the shore power connected or disconnected and results remained the same with a Fault Code of 1.

I know the genset does not have it’s own battery..

Has anyone had similar experiences or have any suggestions.  I do not need it as we will have FHU or will use the genny while traveling for rooftop AC.

Dale, 03 Neptune, 300ISB, 5500 Diesel Onan.

Edited by d.noel@sbcglobal.net
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House batteries were charged when plugged in and also showed charged when trying to start while unplugged.  I'll double check them and all their connections and let you know the results.  thanks for the suggestion.  I thought the genset was connected to the chassis battery.  Ran the test start with the 110 connection and without it.  Tried this to eliminate the transfer switch being part of the problem

 

Edited by d.noel@sbcglobal.net
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I would locate the two large terminals on the back of the generator where the connections are made from the chassis battery. Take a 12 volt battery and set it on the ground and use jumper cables to connect it to those two terminals observing polarity. If the generator starts with the engine off and that battery connected then you have a clue what is going on. Either a bad connection from the chassis battery dropping to much voltage or a contactor that is only making when the engine is running. I know on long runs of the cable from the batteries to the generator Monaco sometimes used splices and those splices have been know to become resistive over time.

 

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Thanks Bob, I will be checking the SG for each cell today but not crazy getting underneath here due to all of the fire ants.   I will look at that as soon as I am on pavement and it will then let me know between the batteries and the genset if there is a problem.  I've had this rig for 3 years and did not change the house batteries but did do the chassis ones.  The house ones could be very old and I'm going to look for dates later today.

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I have two sets of 6V Duracell Golf Cart batteries for my house battery bank.  One cell on each of the pair is very very low on the SG.  The remainder of the cells and all of the unaffected batteries show well.  I will be rewiring the banks to only use one pair of 6Volt batteries to give me a 12Volt system for the house.  Probably done on Saturday.

I am hoping this will solve the generator problem.  Since we do not boondock then there should not be a need to even replace the missing batteries.

Thanks to all for the suggestions.

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I had a very similiar behavior when I was trying to deal with a nearly dead engine battery (my generator starts off the engine battery).  I put a boost on the generator to get it started.  After several minutes, I was able to start the coach.  But, if I stopped the coach soon afterwards, the generator would also die.  Looked to me like the generator required a min. level of voltage on the battery to keep running.  No exactly the same situation as yours, but the symptons are similiar.

steveg 2005 dynasty

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Dale N.

On your 03 Neptune the generator starts from the house batteries.  When you start the engine after the engine batteries reach about 13.1 the Intellitec interconnect relay delay devide (IRD) closes the interconnect relay and the house batteries will receive power for charging.  If you house batteries are discharged too low the inverter/charger will not charge them.  It has a built-in safety.  You will need to use an external charger to get them back to a "safe" state.   If any cells are bad then you should replace the entire bank of batteries as the bad cells will draw down the other cells.  Also make sure your inverter/charger is set to charge.  

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10 minutes ago, Larry J Laursen said:

Dale N.

On your 03 Neptune the generator starts from the house batteries.  When you start the engine after the engine batteries reach about 13.1 the Intellitec interconnect relay delay devide (IRD) closes the interconnect relay and the house batteries will receive power for charging.  If you house batteries are discharged too low the inverter/charger will not charge them.  It has a built-in safety.  You will need to use an external charger to get them back to a "safe" state.   If any cells are bad then you should replace the entire bank of batteries as the bad cells will draw down the other cells.  Also make sure your inverter/charger is set to charge.  

I do have one cell in each of the parrallel pair that is bad.  The battery replacement is our next step.  I appreciate the information as we have only had this coach for 3 years and it is a continual learning curve.

Dale 03 Neptune

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On 2/2/2020 at 2:17 PM, noeldale@gmail.com said:

I do have one cell in each of the parrallel pair that is bad.  The battery replacement is our next step.  I appreciate the information as we have only had this coach for 3 years and it is a continual learning curve.

Dale 03 Neptune

To bring everyone up to date on the results.

Had one cell of each parallel pair that was bad.  Generator would not start unless engine was running and had a code of 1.   Replaced all 4 GC2 Duracell batteries that were coded as Feb 2014.  Found most connections were not as tight as I would have liked.  We bought this coach 3 years ago and did not check the connections.  (My fault).  Now all is working well and the genset starts and does not give a faultcode.

Thank you all who have made suggestions as I did learn some in the process

DaleN 03 Neptune

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