Voltage, well regulated, please...

[Jon Wehrenberg]

With two alternators the house and chassis batteries are charged independently.

I would rather see the voltage at the house battery posts, although it sounds like the house generator voltage regulator is in bulk charge, or there is a problem with it. I would not allow this condition to continue.

You did not say what the house voltage is with the inverters (on shore or generator power) only charging the house batteries, nor did you say how long after engine start the voltage reading was taken, nor the battery voltage prior to engine start.

When Liberty looks at the added wires, they should also check out the house battery voltage issue and I would be inclined to take the belt off that alternator while driving there.

[Jon Wehrenberg]

I have to apologize to Paul and all others for a serious error.

PREVOST DOES WIRE SOME 12 GAUGE WIRES DIRECTLY TO THE CHASSIS BATTERIES, AND DOES NOT FUSE THEM AT THE BATTERIES.

I started digging through Prevost wiring diagrams (all 159 of them) and stumbled across some that show the very wires Paul has on his coach. According to the diagram they are 12 volt, 12 gauge wires going to several circuit breakers in the rear junction box and the DDEC3 feed.

They are not converter wires, and they are not installed after the conversion was done.

[JIM KELLER]

Jon, Don't be so hard on yourself ! A man with 2,695 posts theoretically could eventually have an "error." We will sweep it under the carpet and forget about it.

[Darl-Wilson]

Jon, I am real happy to see this post for 2 reasons. One is that I believe you to be an honorable, honest, and helpful person. Your post just confirmed what we all know. I go along with Jim, don't feel bad. You have made a great contribution to POG, probably more than any other single person. Second reason is that in the course of trying to solve my on-going battery problem I have encountered these small wires attached to the battery posts. They go back into the loom like they were installed in the manufacturing process. I also have the DDECIII system so now I know my coach is normal.(or at least as normal as one of these things get).

Thanks for all your help!!

[Jon Wehrenberg]

Darl, the thing that tripped me up was the circuits that come off your batteries like Paul's, are shown as coming off the load side of the 90 amp 12V circuit breaker on the drawing I referred to when looking for a reason for those wires. On buses with the leads coming from the CB, there is nothing except the heavy cables attached to the batteries.

The moral of the story is never say never, look at ALL the Prevost drawings, and double check.

[phorner]

Jon, Thanks so much for clearing this up!! I do appreciate all of your efforts and you have absolutely nothing to apologize for!

I have an appointment in a couple of weeks at Liberty and was going to question them regarding these "mystery" wires and how they came to be installed in my coach. Of course, being a new owner, I feared the worst and assumed that someone had "tinkered" with my electrical system.

I now feel much better about their presence.

Thanks again for all your research and detailed analysis....

[truk4u]

Jon,

You think you feel bad, I fabricated another board to cover my chassis batteries yesterday and low and behold, same DDEC wires that Paul had while I was in FL. I really didn't think I had them since I just wired in the Quest Charger and had everything apart, but I overlooked it and then told you mine didn't have them.

Sorry guys, I'll double check in the future before I open my yap....

[Darl-Wilson]

Tonight, the individual charging of my batteries was complete and they were all in 13V range and holding. With the 12V and 24V switches off I began reconnecting the cables and the 'Jon' yellow wires. Since I only had a flashlight I was amazed to detect a spark as I connected the 'double wires-in one-connector' to the 12V battery located next to the big bolt/frame ground. I tried to follow the these 2 wires in the near-darkness but they disappeared inside the loom. I finished tightening the bolts on the batteries, including ol' Sparky, then turned on the 2 master switches. I also checked the all of the breakers next to the 12V and 24V switches. Of course nothing happened when I tried to start from the rear. Same results when I tried in the cab. The cab gauges remained the same as they were when this problem began. I then disconnected the offending yellow 12 gauge wire from the battery post and then went through the same starting procedure as I described above. Same result.

Obviously this yellow wire, attached to the + side of the battery, is either grounded or or I have a closed switch someplace on the coach. Tomorrow I am going to go through the 159 diagrams unless Jon remembers something about this and can suggest the diagram number. I would have a mechanic look for this problem but, to my knowledge, we don't have anyone in the Reno area that knows anything about a Prevost.

Will the factory or the Prevost service center in CA give some advice or guidance in a case like this? This problem might require a lengthy dialog. At this point that might be my only option unless my towing insurance is willing to do a 600 mile tow to Prevost. Sure! I do have a Good Sam breakdown policy but I don't think this is something they would pay. Any ideas appreciated...again.
Thanks,
Darl

[Jon Wehrenberg]

Darl.....here I go again. I hope it is right this time. If you are going looking I am using pages 91 and 95 of the 159, drawings D060873 rev 022 P.1 and D060873 rev 24 P.2 respectively. I have no clue what serial numbers these revision levels include, but the areas of concern do not seem to have been revised.

With respect to the spark, the 12 ga. wires coming off the 12V post go to CB19, CB20, and CB21. Your listing on the bus rear door should tell you what they are for and from that you can determine if they are hot. The second lead goes to the DDEC feed.

That may explain the spark. It would be worth while to measure the amps just to get a sense of how big the load is, although with freshly charged batteries it likely has nothing to do with the starting issue.

As to the starting question, on P.2 you can trace the start circuit power from the rear junction block (RH side of the drawing) through CB16 to the rear start switch. Obviously if there is not 24V at the wire number 89 at the switch or CB then something is wrong, either the CB is open or the power is not getting into the rear box. If there is no power there then the problem must lie with the big breakers on that stainless steel panel above the master cut-off switch.

For the moment I will stick with my previous guess that it is the 90 amp breaker. BTW.....Kim Sloan owned my coach originally, and he was very good at revealing a little of its history. One of the things that showed up very early in the life of the coach was the breakers shown as 90 amp on the drawing were failing evidently because they were near their limit. After a couple of scary incidents on the road where his coach shut down, Prevost replaced the 90s with 105s. He said the problems went away.

I am not focussing on the breakers because of that, but that may be a clue as to the problem. The drawings clearly show a failed breaker will shut off power to the rear box and along with it any power needed to engage the starter.

[truk4u]

I think we jumped threads for Darls problem, but I'll stay on this one.

Darl,

I think Jon is dead on with the CB. Try these steps just to get started unless your well beyond this..

1. Power to the Jump Lug is before the cut-off switch and should be 24+

2. Voltage at the big red terminal on the starter/solenoid should be 24+ and that proves the cut-off switch is working

3. Remove the plastic panel behind the CB's and check that current is passing through as Jon suggested. You can't just push them, put a meter across and verify. On mine, CB6 goes to the junction box.

I'll leave the rest up to Jon so as not to muddy the water.