Generator starting problem,Help!

[zman62]

Every time I post you guys are so helpful. Ok, here is another,07 Camelot. Generator has always labored started regardless of voltage. Sometimes it just wont start unless I start coach. I get very little voltage drop during start at house batteries. However get large drop at generator. It will drop to 8v at gen but its at 11.9 at batteries. Looking at Onan manual it is very specific as to how it should be grounded. It is not grounded as manual want. I am thinking of adding a battery just for gen that will sit next to gen. Will ground to chasis as well as ground cable to generator. Pos from house batteries to pos of new batt then to pos of gen. This will allow it to charge off coach it will have short cables and much more cranking power. Hopefully no voltage drop.

Please let me know your thoughts... Thanks!

[itdave]

Here are some ideas. First connect a jumper from the Generator negative cable to the chassis near the generator. If the generator will then start it would show that you have a poorly connected ground for the generator. If this does not help I would jumper the generator 12 volt positive connection to the house battery positive, you should be able to make that connection in the front run bay. This should tell you if you have a problem with the positive or negative connection. Once you figure that out you can follow the wires back to were they connect to either the house positive or chassis. I think it is more important to find the problem instead of doing a workaround.

[bigskymt]

Put your meter between +12vdc at gen and GOOD chassis ground and measure voltage at cranking, if you drop voltage you have a bad +12vdc supply to the gen. If not you have a bad ground.

[zman62]

The wires going back to the house batteries are almost impossible to follow. They are all in the belly of the coach. Today I jumped it with my truck while it was hooked to the house batteries and a voltage drop to 8 volts. According the the install manual it should have a ground to the chasis as well as to the neg on the battery. Its done it since new and its been to the Onan dealer. I can always get it started but would like it to be simple. My thought was adding another battery never hurts it will just be locate right next to the gen.

[nodine]

Quote:

Originally Posted by zman62 The wires going back to the house batteries are almost impossible to follow. They are all in the belly of the coach. Today I jumped it with my truck while it was hooked to the house batteries and a voltage drop to 8 volts. According the the install manual it should have a ground to the chasis as well as to the neg on the battery. Its done it since new and its been to the Onan dealer. I can always get it started but would like it to be simple. My thought was adding another battery never hurts it will just be locate right next to the gen.

So how did you jump it to the truck? Where are you measuring the 8 volts? It makes a big difference when troubleshooting. If you connected the truck to the house batteries and the voltage still dropped to 8 volts at the house batteries then you a placing a huge load on the system. Sounds like maybe a bad starter in the Onan generator. If you go under the coach and connect the jumper cables from your truck directly to the battery input connections on the generator and the gen still labors to start then you have eliminated a bad connection from the house batteries. It also means that placing an additional battery near the gen set will not help.

If when you connect directly to the back of the gen set and she starts fine then you have a connection problem to the house battery. I believe there are large splices in the battery cables that run from the rear of the coach to the front of the coach. These have been reported to become resistive and make poor connection. You will not notice the resistive connection for small loads but a high current draw will drop voltage across the poor connection.

In summary I guess you have either a bad starter on the gen set, or a poor connection in either the ground or positive or both connections to the house battery.

Good luck,

Bob

[zman62]

The starter was replaced under warr about 6 months ago. It wasnt bad but they were throwing parts at to fix this problem. I hooked the truck to the 6 foot cable coming off of the back of the gen. However I was not able to get the ground hooked to the back of the gen so I grounded it the best I could. I am going to hook up a seperate battery today with battery cable to the back of the gen. This should tell the story I hope.
The 8 volts was measured during jumping at the back of the gen. I really think if the battery is grounded right to the back of the gen and to the chassis the problem will go away. We will see.

[zman62]

Ok, I hooked up a stand alone 12v battery 600CCA directly to the gen. Got barely a 2v voltage drop during cold crank which is with in spec. Had it grounded to the battery and to the chassis. Then I removed battery and hooked it back up like from the factory. Got a 4 plus drop using 4 6v batteries which should not even feel that gen crank. I had my meter ground to the chassis and then to the positive terminal of gen. My thought is add another ground from gen to chassis so there is two. Otherwise I have a high resistance junction somewhere from house batteries to gen. Not an easy find if thats it. Thoughts???

["007"]

Batteries are normally grounded off battery neg to frame of chassis. Your Gen should have a ground cable off it to frame of chassis. One of the ground cables to frame may have a high resistance connection to frame.
You can run a new battery cable to frame from your Gen as you said BUT if the poor ground is off house batteries to frame of chassis may still have voltage drop.
Replace both ground cables or find frame connections and clean them up with new bolts and star washers so they will stay tight. Also protect connections with some battery spray paint.

[zman62]

I think I am getting closer. I have spent the day cleaning any and all connections. I have determined that I have no drop at the house batteries but I do have a drop at the T junction on the firewall. This is fed from the back of the coach then Ts off to the gen and the electrical panel below the driver outside. The feed comes from the house batteries into the passenger rear electrical comp. Through the generator breaker (buss) then out the back of that compartment. This is where I loose it. I don't think it goes out the back of that compartment and straight line run to the T junction at the firewall. Does anyone out there know if there are any junctions,relays etc between that pass rear compartment and the firewall T junction? I have looked at the schematic but its no help in that area.

Thanks again for all the help!

[nodine]

Quote:

Originally Posted by zman62 I think I am getting closer. I have spent the day cleaning any and all connections. I have determined that I have no drop at the house batteries but I do have a drop at the T junction on the firewall. This is fed from the back of the coach then Ts off to the gen and the electrical panel below the driver outside. The feed comes from the house batteries into the passenger rear electrical comp. Through the generator breaker (buss) then out the back of that compartment. This is where I loose it. I don't think it goes out the back of that compartment and straight line run to the T junction at the firewall. Does anyone out there know if there are any junctions,relays etc between that pass rear compartment and the firewall T junction? I have looked at the schematic but its no help in that area. Thanks again for all the help!

zman,

You might be interested in this thread:
Battery Harness Failure on 2007 and Later Coaches

Good luck,

Bob