Generator Not starting unless coach engine is on

[cotten31]

I just bought a 98 Monaco Dynasty. 7.5 HDKAJ Diesel generator.
If I try to start the generator without the engine on, I hear the starter engage, but it will not turn over. If I start the coach engine, the gen will start up. Is this a sign that the batteries are weak?

I see that I have 2 shelves of batteries in a side compartment of the coach. Are both these batteries for the coach engine as well as what feeds the lights inside the coach?

I don't have any manuals.
Thanks for your help.

[Mr_Mark1]

Prism, I'm still researching Prevost . I'm ALL over the Prevost website learning and discovering that they have just as much trouble as we do! LOL! Always something that needs attention!

I think I have it down to two or three manufacturers, Marathon, Millennium and maybe Liberty Coach. One thing that I have learned is that they are made differently depending on the converter.

Marathon doesn't use Prevost slide-outs and uses hot-water tanks instead of the Aqua-Hot system.

Millennium uses Aqua-Hot and Prevost brand slide-outs. Marathon uses two inverters, Millennium uses four. They each have their own reasons for their particular set-ups.

It takes 6-9 months to build a new coach. I haven't contacted the converter yet, still reading and deciding. As you know, its a major commitment once the decision is made.

And, on the generator issue.... replacing the chassis batteries probably did correct the connection issue.

MM.

[prism]

Mr.Mark wrote:

prism wrote:

Mr.Mark wrote:
We had the same problem about 3 yrs. ago. The engine would start fine but the generator would not unless the engine was running.

The service shop said our engine batteries were too low. Changed out the two chassis batteries and problem solved.

I know it doesn't make sense that the engine started but the genny would not. I just changed the 8 house batteries this year with AGM's.

MM.

IF your two 31 series would start the main diesel engine they would also start the generater.I suggest you have a power drop(resistace)
between your chassis batterys and the generater.The new batterys probable had just enough extra umff to override this defect

--------
You do realize it has been over 3 yrs. ago and no problems since the new chassis batteries. If it happens again, I'll have it checked out but why kick a sleeping dog?

MM.

true.But CS tells me if the batterys start a big 9 litre cummins diesel engine they should start a little gen set.Probable the connection to the gen set right at the main batteys was poor and when putting in new batterys that was corrected
Did U buy your new marathon yet?

[Mr_Mark1]

prism wrote:

Mr.Mark wrote:
We had the same problem about 3 yrs. ago. The engine would start fine but the generator would not unless the engine was running.

The service shop said our engine batteries were too low. Changed out the two chassis batteries and problem solved.

I know it doesn't make sense that the engine started but the genny would not. I just changed the 8 house batteries this year with AGM's.

MM.

IF your two 31 series would start the main diesel engine they would also start the generater.I suggest you have a power drop(resistace)
between your chassis batterys and the generater.The new batterys probable had just enough extra umff to override this defect

--------
You do realize it has been over 3 yrs. ago and no problems since the new chassis batteries. If it happens again, I'll have it checked out but why kick a sleeping dog?

MM.

[wa8yxm]

I see two possible problems both with the house batteries.

1: As discussed above, Bad batteries (wore out)

2: Bad (dirty) connections in need of cleaning.

Question: (before you ask) HOw do you know it's the house batteries?

ANSWER: The engine starts, it is much harder to start the engine than the generator so if it works when the engine is running, It has to be the house batteries.

Recommendation: PM the connections (Clean) and have the batteries load tested as described above.

What was I doing yesterday: PMing the connections of course.

[nodine]

Remember the batteries are at the rear and the gen set is up front. That means quite a run of cable to connect the batteries to the generator. As someone else said, check the cable connections at the rear of the generator. Unfortunately, Monaco usually did not use continuous length battery cable runs and put splices along the way in the cable chase. These splices have been known to become resistive over time. If that is the case the best solution may be for a battery up front as suggested.

Bob

[prism]

Mr.Mark wrote:
We had the same problem about 3 yrs. ago. The engine would start fine but the generator would not unless the engine was running.

The service shop said our engine batteries were too low. Changed out the two chassis batteries and problem solved.

I know it doesn't make sense that the engine started but the genny would not. I just changed the 8 house batteries this year with AGM's.

MM.

IF your two 31 series would start the main diesel engine they would also start the generater.I suggest you have a power drop(resistace)
between your chassis batterys and the generater.The new batterys probable had just enough extra umff to override this defect

[Mr_Mark1]

We had the same problem about 3 yrs. ago. The engine would start fine but the generator would not unless the engine was running.

The service shop said our engine batteries were too low. Changed out the two chassis batteries and problem solved.

I know it doesn't make sense that the engine started but the genny would not. I just changed the 8 house batteries this year with AGM's.

MM.

[Canadian_Rainbi]

gb76087 wrote:
Had the same problem over the weekend. Generator wouldn't start and remote panel was only showing 10.5 volts. Started to remove the house batteries to take them for a load test. [COLOR=]Found loose battery cable. It appears to have solved the problem.

This is a real possibility.

[FormerBoater]

JetAonly wrote:
I have a 2000 Dynasty. The chassis battery starts the Generator. If your chassis battery starts the Cummins then it is OK to start the Onan. Check the Positive from battery to genny, Then check the gennies connection to ground. The Onan's +/- connection studs are on the backside of the generator, driver's side.

Don't know if this is your issue, but a buddy with a Monaco coach had big generator start issues and found that the length and size of the wiring from the battery bank to the generator did not meet Onan specifications.

He installed a dedicated battery close to the genny....problem solved.

[JetAonly]

I have a 2000 Dynasty. The chassis battery starts the Generator. If your chassis battery starts the Cummins then it is OK to start the Onan. Check the Positive from battery to genny, Then check the gennies connection to ground. The Onan's +/- connection studs are on the backside of the generator, driver's side.

[prism]

thgoodman wrote:
I had the same problem since I bought our '06 Beaver (Monaco, out of warrantee) in '08. Finally got sick of starting the coach engine every time I wanted to use the generator. Took it to the Cummings dealer across from the Monaco plant in Coburg, OR. The solution was simple but expensive. Monaco cheeped out in the 12v cable the ran from the battery to the generator and it couldn't carry the current (hence, big voltage drop). Replaced the cable with a #0000 welding cable (probably over kill, big $$$, almost 50' long) and the problem was solved.

Before you spend a bundle on a bank of new batteries, try this to confirm your problem. Hook a good set of jumper cables from a good power source to the gen. right where the battery cables attach from the coach to the generator assembly but before the starter solenoid. Try to start the gen. In my case, the generator started instantly. YMMV

I wonder two things here How many beavers were produced with the wrong gen start cables and I wonder how this ever got through final inspections at factory and at dealer and why the previous owner whom bought it new would have not wanted that fixed at the time he bought it??

[gb76087]

Had the same problem over the weekend. Generator wouldn't start and remote panel was only showing 10.5 volts. Started to remove the house batteries to take them for a load test. Found loose battery cable. It appears to have solved the problem.

[thgoodman]

I had the same problem since I bought our '06 Beaver (Monaco, out of warrantee) in '08. Finally got sick of starting the coach engine every time I wanted to use the generator. Took it to the Cummings dealer across from the Monaco plant in Coburg, OR. The solution was simple but expensive. Monaco cheeped out in the 12v cable the ran from the battery to the generator and it couldn't carry the current (hence, big voltage drop). Replaced the cable with a #0000 welding cable (probably over kill, big $$$, almost 50' long) and the problem was solved.

Before you spend a bundle on a bank of new batteries, try this to confirm your problem. Hook a good set of jumper cables from a good power source to the gen. right where the battery cables attach from the coach to the generator assembly but before the starter solenoid. Try to start the gen. In my case, the generator started instantly. YMMV

[Bobbo]

Have all of the batteries load tested at an auto parts store. It is usually free. It definitely sounds like you have low/dead battery(ies).