Voltage, well regulated, please...

[phorner]

I have noticed that when I start up the bus and let it run, I am seeing in excess of 15 volts on the gauges, both house and chassis batteries.

Additionally, my inverters shut off and the display for each indicates over-charging of the batteries.

So, am I correct in thinking that the voltage regulator needs replacement or simply adjustment?

And, if adjusting the regulator is the answer, how would it have gotten "out" of adjustment, or does this indicate that something is going on with the alternator?

[Darl-Wilson]

Paul, I may not be the best person to answer this but I recently had a similar experience and found that the battery cables on the house batteries were corroded. I was at a repair facility in Eugene, OR and the mechanic diagnosed this as being a problem with my batteries. As a long-ago, ex-service manager I checked this out on my own and noticed the corrosion. Even though the mechanic, who insisted new batteries were in order, was reluctant to take the advice of an "amateur", did as I told him. That little correction eliminated the need for several thousand dollars in new batteries. As I understand it the mechanic is no longer with this company. This occured in August of this year. I have not had a problem since.
I am sure someone else (Jon?) will jump in and give you some more help and maybe better advice but this is what worked in my case. It certainly won't harm anything to check this out where making ill-advised adjustments might harm the batteries by overcharging them. Good Luck!!

Darl

[dalej]

Paul, your voltage regulator might be built in to the alternator. In this case you can just take the
alternator in and have it checked. Mine is a stand alone regulator so I just replaced mine when I had
irregular readings, mine didn’t adjust and was cheap! I’m not sure, but don’t think many do.

[garyde]

After replacing my Chasis batteries, I still had low voltage readings, the people at Gem Equipment in Ventura (Detroit Deisel & Allison dealer)diagnosed the problem as bad regulator. I ordered a new regulator from Prevost , replaced the old one. No more problems.

[lewpopp]

Dale...What is considered "cheap" on this forum? Remember, we're not all PPs.

Just kidding...Tomorrow I get to watch the "expert" work on Paul's coach. The Trukster is here and he'll perform a miracle for Paul

Speaking of miracles. Paul, since he purchased a Liberty, is waiting for the pope (JON) to appoint him bishop. i. e. Anyone who has a Liberty is closer to God than someone who doesn't.

Nothing else to write about except we proclaimed this a Micro-POG here at ODR. Truk couldn't believe that he ate his meal tonite and no attack came from any angle.

[Jon Wehrenberg]

Paul,

Before you go running and changing alternators and voltage regulators I think the problem (if any) should be confirmed.

If I am correct you have a large alternator located between the engine and the AC compressor, and a second alternator located near or on the fan gear box. If that is correct, what are the odds that a dedicated chassis and dedicated house alternator and voltage regulator are both overcharging by the same amount.

My starting point would be to use a good multitester and check voltages at both sets of batteries.

[phorner]

Thanks for all the responses. We (Truk and I, with a cameo by the Lewster) will undertake the installation of the Guest Marine battery charger for the chassis batteries today. Should be painless and straight forward!

I don't know for a fact that the chassis batteries are being over charged by the alternator, I'll check the voltages with the bus running.

What I have seen, is that with the bus running, the inverters shut down, and the "blinking" panel for both inverters indicates an over-charging condition. I'm guessing that if the inverters sense too much voltage being applied to the house batteries that they then shut down and display this "over-charging" condition.

Since the inverters only do this when the bus is running, I'm figuring that the first place to look for a solution is the charging voltage from the alternator via the voltage regulator.

At least, if I can accomplish the charger installation, I can then be assured of being able to move the bus, should the need arise.

By the way.... I've yet to have the pleasure of attending a POG Rally, (we have a self-proclaimed Micro Rally taking place here, complete with a chassis electrical demonstration) but have any of you noticed Lews' love of garlic??? I'm wondering if the sod farm is a cover for a secret garden .......

[Jon Wehrenberg]

We need to use precise descriptions of the situation. For example, with the bus running, is the coach still connected to shore power?

An inverter is a charger when it sees a 120V supply. An inverter stops functioning as a charger, and instead converts (inverts?) battery voltage direct current to 120V alternating current when that 120V supply is disconnected.

When it has shore power connected, and the engine is running, the battery charger portion of the inverter likely senses charging current from the alternator and reduces or turns off its output to the batteries.

So......step two in the process is IF there is a 15V house and chassis condition (which seems doubtful) is to turn off the inverters and recheck the voltage at the batteries.

Remember, the inverters have nothing to do with the chassis batteries making them an issue highly unlikely.

[dalej]

I am seeing in excess of 15 volts on the gauges, both house and chassis batteries.

This kind of threw me a bit, chassis batts should be reading in the 26v range. Can you detail this reading.

[Joe Cannarozzi]

We can not charge the chassis with the inverter but CAN charge the house with the 8-V if the equalizer switch is on.

However, the charger in the inverter will automatically adjust according to the state of the batteries and draw on them if supplied with a/c current while the engine is running and equalizer on.

If your house batteries were all charged up but chassis batteries were very low and the reg. has the charge rate cranked up and you have the chassis and house equalized that scenario may overcharge the house?

[phorner]

Just to add to the mix, how does the generator battery get charged?

Also, the bus was disconnected from shore power with the engine running, when the inverters displayed the "over charging" condition. I tried shutting them off, then back on, in an effort to reset them, but it made no difference.

[Joe Cannarozzi]

If there was no a/c current being supplied to the inverters and they still displayed overcharge that would lead me to believe you have an inverter fault of some kind, that's just a guess. That is not to say that you don't also have another issue.

These are the most fun, simultaneous failures in a common system.

Your gen battery should be getting charged by the gen. alternator.

Our control panel also includes a second equalizer switch, but 12 volt, that enables us to charge the 12 volt bank of house batts. with the gen. alternator or use the house to jump start the gen. if need be.

If a/c current is being supplied and the inverters are on we can also send a charge to the gen. battery from the inverter by engaging the 12 volt equalizer switch.

This is all stuff that I had to figure out on my own through time and experimentation. Even though we received a full set of converters manuals many of these functions were not discussed and our converter, Hickox, is no longer around.

[Jon Wehrenberg]

Joe, you are 100% correct with respect to your coach. We still don't know from Paul if he has 2 alternators so to answer his last question we need to make educated guesses so I try to remember to phrase my answers in that regard.

I think his generator battery is charged via the inverters when connected to shore power, and via the generator alternator as you suggest when the generator is running. This is a real gray area for me and I am speculating. I believe he has an isolator that separates that battery from the house, so the house battery condition does not adversely affect his generator start battery.

I think his engine charges both sets of batteries independently so I question his common 15 volts on each set of batteries.

Paul, Two alternators? What is actual voltage at batteries with engine running? With engine running and inverters connected to shore power what is the voltage at the two sets of batteries and the generator battery?

You should be able see slight changes in voltage at the batteries as you change conditions, such as engine off, inverters off, etc. because each regulator probably is set up for slightly different voltages. Divide the 24V side of the chassis by two.

[dalej]

The system that I have allows the generator battery to receive charging by

1. The Detroit running, is charging the house, cables connect house batts. to gen. bat. thru an isolator.

2. Generator is running, invertors are charging the house batts feeding current to gen. batt. like in #1

3. Shore power is charging house batts thru the inverter and feeding gen. batt. like #1

Note: a isolator allows current to flow in only one direction so the gen. batt. doesn't drain when the
house volts go down.

[bill&jody]

1. The Detroit running, is charging the house, cables connect house batts. to gen. bat. thru an isolator.
so, does that mean defective (old and tired) gen batt could pull down the house batts, eg. when boondocking?

wmm

[Jon Wehrenberg]

Unlikely Bill,

There should be an isolator. But with a battery tester it is easy to find the condition of the generator battery, or just take it off line by disconnecting it.

Almost 100% of the investigative work can be done with a multitester and some time. Back in the dark ages when I had issues, I would just isolate things one at a time until the problem showed up.

I don't have a clue as to how the generator battery is isolated in all coaches, but on my old coach the "isolator" between the chassis and house batteries for example was nothing more than a big solenoid (relay) that closed when there was charging current from the alternator. If the alternator was working, the house and chassis batteries were joined by the closing of the circuit through the solenoid (relay). As soon as the alternator stopped functioning such as turning the engine off, the solenoid (relay) opened and both sets were separated from one another. Classic simplicity.

I am sure there is some means of isolating the generator battery from the house as soon as charging of the house batteries stops so the generator battery and the house batteries can not adversely affect one another.

[dalej]

Bill, just when you are starting the generator. That is the intent of the cross over, to charge the gen. bat. and to use the house batts if the voltage in the gen. bat. is lower then the house batteries when starting the gen.

[phorner]

As an up-date, there are 2 alternators that are used to charge the batteries on my coach. With the engine running, and disconnected from shore power, the chassis batteries are measuring 27 volts, which sounds fine to me.

However, under the same conditions (engine running and disconnected from shore power), I am measuring 15.2 volts at the cigarette outlet in the dash, which is the only place that I could find to measure voltage directly. Additionally, my analog dash gauge for the house batteries also reads slightly in excess of 15 volts, which kind of confirms to me that the house batteries are being slightly over-charged when the engine is running.

Does this sound like a reasonable conclusion?

I have also found 1 voltage regulator, located on the bulkhead by the chassis batteries and the chassis battery disconnect switches which is adjustable, but I believe that this regulator adjusts voltage to only the chassis batteries, which appear to be OK, reading 27 volts.

Any ideas or comments?

[garyde]

My Alternator provides power to chasis and coach batteries thru the regulator. When the engine was running, and I had a bad regualator, the voltage to my coach batteries went way up into overload. At the same time, my chasis batteries were reading low voltage .

[Larry W]

I am not certain, but I think the lighter may get it's power from the 12V side of the chassis battery system, the same as the 12 volt chassis lights.
On my coach the engine alternator will charge the house batteries at about 15 volts when the engine is first started. As the engine run time increases the charge will decrease slowly to 13.8 volts. The timing seems to be tied to the batteries state of charge. It never seems to stay high for more that 15 minutes max.

[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.:D 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).:rolleyes:

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.

[win42]

Darl: On My Royale I had similar yellow wires directly connected to the batteries. I moved them to the 24V disconnect switch so they will be off with the switch open. No apperant problem developed after doing this, except the batteriers stay charged with the switch off. I think I traced the wires to the inverter that changes 24V to 12V for the headlights. We don't need headlight power when parked with the switches off. I am no electrical guru for sure, but this worked for me. I leave a 24V "Battery Tender" on the starting batteries when parked.

[Jon Wehrenberg]

Truk, no problem jumpin' in because both your coaches are closer in age. I have stopped referring to my coach and I am trying to stay with the wiring diagrams that seem to most closely relate to Darl's.

I don't think Darl needs to spend the money for a tow or repairs because this thing is due to a single problem, as yet unidentified. I believe we can all work through this and get him running again.

Harry, I think you did the right thing. That is exactly how Prevost has done that on some coaches (and why I screwed up so bad) and their wiring diagrams show those wires at the big CBs.

[Darl-Wilson]

Tom, Jon, and Harry, thanks for the great advice. I have to take my wife to the Dr. so I will check this out when I return and post the results. I certainly don't want to go to the expense of having someone poking around for something they don't know about and charging me a fortune. What all of you wrote makes real good sense. The weather has changed a bit so hopefully it will cooperate while I work on the home. Thanks again!:)

[Jon Wehrenberg]

Darl,

Here is the procedure I would use to check this, and why.....

I assume your batteries are up to their desired voltage and are connected according to the Prevost diagram. Obviously this is essential to insure you get the right voltages to the 12V and 24V circuits.

Verify 24V at the big cable on the starter. This proves the 24V master is closed. This cable does not go through any CBs, just through the 24V master switch to the solenoid.

If OK, verify 24V is in the rear electric box. This is essential. If it is not, it means power is not getting past CB6 (that number may need to be verified, but it is the CB that feeds the rear box.

If OK, and there is 24V power to the rear box, power to the rear start switch passes through CB16 (again verify that number). If there is power to the rear start momentary contact switch, there should be continuity between wire 88 at the momentary contact start switch all the way to the starter relay coil R4. If OK there is no reason to not hear a click when the engine control switch is in the rear start position and the rear start switch is pushed.

If there is continuity and it has been confirmed, if a push on the rear start button does not produce a click in the R4 relay the relay may need to be replaced. If you hear the relay, and the starter does not engage, check for 24V at one side of the R4 relay. This should be at wire 24R, a 10 ga. wire. The other side, wire 86 goes towards the starter solenoid.

I still think you are going to solve it where I have highlighted it in red. I got my neck stuck out a country mile on this Darl, and if it turns out different than that, do me a favor and lie so it looks like I know what I am doing.

[truk4u]

Jon,

Your wire numbers are identical to my 99 chassis and should match Darl's.

[Darl-Wilson]

I am back at my office for a while but I stopped at home for a bit when I came back from the Dr. I removed the cover on the rear circuit breaker and with some limited testing found that I only have 12V back there including the 24V switch. I tried CB6 and had nothing. Tried with both master switches on and off. Still nothing. This may be just as you all suspected from the start, a circuit breaker. Now, my questions are; if this has indeed failed (I will double check it in the morning) should I replace it with a 105amp and where do they sell this type of breaker? Smith Power Products, Detroit Diesel does the service on my Prevost but they order the CBs from Prevost.
Again,everyone, thanks for all your help. I hope to return the favor one day soon!

[Jon Wehrenberg]

Darl,

It may not have failed. It probably tripped, but you haven't got enough force in your thumb to reset it if it is like the ones on mine. I had to hold a screw driver flat blade on the face and push like hell with both hands along the length of the screwdriver. It hardly moves when it resets, but there is a distinct snap so you know it reset.

If it did in fact fail I would replace it with the same size unless the coach has had problems which I doubt.

[Jon Wehrenberg]

Darl,

The guy that nailed this from the git-go, if it is in fact the CB was George (Toy Box). The only reason I came back to this was I think somewhere you said the CBs were OK, and my look-see at the wiring diagrams kept bringing me back to what George said.

Good job George.

[truk4u]

Darl,

The question is:

Do you have 24+ volts between the master switch and one side of CB6?

[Darl-Wilson]

Tom,

The answer is:

NO

I only have 12.8V on any place I could check throughout the CR area or at the starter. I have not made that specific check yet. I am going to try the Jon starter/screwdriver trick on the CB6 when I get home. If that don't work I will check the voltage between the master and the back of the #6 breaker. I have been looking for a 90amp CB here in Reno but to no avail. I just signed up to buy parts from Prevost direct in case I can't get the the CB reset. Thanks for your help Tom.

[Jon Wehrenberg]

Darl,

If you assume the breaker is open and you can't reset it, just for purposes of confirming it is the breaker, turn the master off, join the cables from each side of the breaker (now everything is unprotected, but thats OK temporarily), and with the master back on, you should be able to get 24V in the rear box, and it should start.

Then you can replace the breaker.

In the category of useless information, on my old coach I had a large breaker for the OTR air system that tripped. I pushed on all the breakers as I am sure you did and I still had no luck so I opened the electric boxes and started checking for voltage. I came to the big breaker and found it was open despite having pushed hard on it. So I pushed until my thumb hurt and it still did not reset. That's when I got the screwdriver and was able to push with the force of two hands.

The breaker was failing so after it tripped a couple more times I got a replacement from Prevost. The replacement had a different reset button and was easier to reset. You may find this to be the case with the replacement you order.

[truk4u]

So if there is no 24v between the master and the CB, your master switch is open! What is the voltage at the Jumper Lug?

If there is 24v at the lug that means there's 24v at the master switch.
If you don't have 24v coming out of the master to the CB, bad Master.

If you have 12.8 at the lug, you have some serious battery cable issues and the paralel/series hookup is suspect.

1905

[JIM KELLER]

Tom, With that drawing I think you need some chalk and a blackboard to do a seminar at our next Rally. Right up there at the front of the class with Jon !

[Darl-Wilson]

Tom and Jon, I checked this out last night and, with your new suggestions,again this morning. The maximum reading I got was 12.8V. The breakers are OK but I only get the same 12.8V across them. Same with the master and from battery to negative on jumper lug. The main check that I think I should have been making (and stupidly didn't check earlier)is simply to see is I am getting 28V out of my battery bank. This is also 12.8V. There is an equalizer that has a 28V lug, a -lug, and a 12V lug. 12V measures 12.8 but the 28V yields a .59. One cable from the equalizer was placed on a negative battery post. When changed to a positive battery post the equalizer read properly except no 28V. I still do not have 28V anywhere in the engine/battery compartment, including the starter. Tom, I think you are on to something when you wrote about the battery cable issues. When this problem 1st occurred the road service company sent out a guy with a 1976 Chev 1/2 ton PU with a battery jumper connection hanging out of the grill. I told him there was no way this was going to get the bus started and I had ordered a commercial truck service truck. He insisted that he could get me started. When it didn't work he called back to his boss who had him remove the battery cables and charge each battery separately. Of course this didn't work either. The second company, with a similar setup but with 4 12V batteries was unable to jump start with the batteries so he jumped it from the starter.

Other than the cable I described above that was apparently mistakenly placed on a - post there is nothing obviously wrong with the cables. Of course there has to be if the batteries are fully charged and connected properly and only check out a 12.8V.

As it stands right now I may not be able to get back on this until Saturday. My whole family, wife, kids, and grandkids are leaving about 4:30am tomorrow for 2 weeks in Puerto Vallarta. Saying everything is in disarray is an understatement!

I am going to get into my Prevost schematics and thoroughly check out the cable configuration on the batteries. I suspect everyone that has helped me on this has wondered if I did something wrong. At this point I think I amy have overlooked the obvious. More to come. Thanks everyone! I'll keep you updated.

[Jon Wehrenberg]

Darl....the following is a direct quote from post #34....

"Here is the procedure I would use to check this, and why.....

I assume your batteries are up to their desired voltage and are connected according to the Prevost diagram. Obviously this is essential to insure you get the right voltages to the 12V and 24V circuits....."

Perhaps rule number one should be to never leave anyone without Prevost specific experience and knowledge alone with your coach, and after anyone touches your coach verify what they did and if it was right.

[truk4u]

Yep, they really screwed up your batteries and you didn't tell us they had been unhooked by Bubba who probably never even heard of parallel/series. Do you have the Prevost diagram showing the 4 batteries and cable placement? If not, let us know and we can put one up here on the board.

To eliminate any further potential in damaging the equalizer, just unhook the ground cable at the equalizer until all this gets sorted out. You won't need the equalizer for now.

Jim - No way, that's Jon's forte:p

[Danss]

Since Darl is taking a break from his agony I have several questions. I now have the 2611A Guest Battery charger. Truk, I believe you said You may could send me a diagram on how to hookup. Also what is approx. location of the plug for the block heater which I believe I can plug charger into (not sure I understand this) I know as much about electricity as I do Brain surgery, so please be gentle with me. Thanks, Dan

[JIM CHALOUPKA]

Dan, you could be shocked to find out how much you know! :D:D:D

[Joe Cannarozzi]

The diagram on the left is how the chassis batteries are wired.
24 volts can be achieved both ways but our start batts. are as the left pic. is.

[Danss]

Charger has 2 plus wires and 2 negative wires. Can youd escribe how they hookup on your diagram? Thanks, Dan

[Joe Cannarozzi]

Better wait for Truk on that one Dan.

Dan the cord for our block heater goes up to a junction box on the upper firewall above the engine. That junction box also has 2 outlets on it.

It should be staring you right in the face when you open the engine doors or you ain't got it.

[truk4u]

Dan,

Sorry for the delay, you sent me an e-mail while I was traveling and it was saved on my laptop. I'll get the drawing scanned and show you how to connect the Quest. It's a great charger and I think Paul Horner will verify that. Hopefully I can get it done tonight.

[phorner]

Dan,

Once you get the schematic from Truk, it will be a snap. Since he guided me through my installation, everything has been fine. It's a really great battery charger and I'm sure you will be happy with it.

Happy wiring......

[Jon Wehrenberg]

Joe,

Be careful assuming all coaches are alike. Darl has the coach battery wiring diagram for his coach on the door. Yours and his may be exactly alike, but as I found out Prevost has not been shy about making revisions.

[truk4u]

OK Dan, here ya go... But first a disclaimer.... This has worked for both Paul and myself based on the Prevost chassis battery setup and both of ours are 99 chassis. If your not real comfortable with messing with the electrical stuff, please get some help from someone with experience. This should work on any of the battery configurations, but please proceed with caution. Also, I would remove the equalizer ground wire at the equalizer in case someone makes a boo boo. There are two drawings, the 1st one is my cable setup and the 2nd is the Quest hook up. If I drew it on one sheet, all the wires may be confusing.

1908
My 2000 CC, 99 Chassis cable set-up

1909
How I hooked up the Quest Charger

Let me know if you have any questions and don't drop a wrench on the batteries!:o

[truk4u]

Dan,

Forgot about the plug... My CC has a 110V plug in the passenger side engine compartment with a switch on the dash labeled "charger". It must have been an option at the time, so mine was real easy.

I did the same thing on my Marathon as Paul did using the block heater receptacle in the passenger side engine compartment. On his Liberty and my Marathon, that 110v plug was controlled by a circuit breaker inside. When you wanted the 110v block heater, you plug in the heater cord located up near the oil reservoir and then throw the breaker. Paul figured he would never use the block heater, so he just used that source for power. When he wants to turn on his charger, he just throws the breaker and he's good to go. You can leave in on, the charger has a float cycle. Be sure to turn it off when unplugging, the inverters don't seem to like the charger and on my Marathon, the inside lights would lightly pulsate when inverting with the charger on.

Hope this helps...

[MangoMike]

1911


I have the same Guest charger on the '97 Liberty and this is how I wired it.

Based on your battery cableing configuration you just have to find the primary postive terminal and the primary Negative directly to the ground.

[garyde]

Tom and Jon, I checked this out last night and, with your new suggestions,again this morning. The maximum reading I got was 12.8V. The breakers are OK but I only get the same 12.8V across them. Same with the master and from battery to negative on jumper lug. The main check that I think I should have been making (and stupidly didn't check earlier)is simply to see is I am getting 28V out of my battery bank. This is also 12.8V. There is an equalizer that has a 28V lug, a -lug, and a 12V lug. 12V measures 12.8 but the 28V yields a .59. One cable from the equalizer was placed on a negative battery post. When changed to a positive battery post the equalizer read properly except no 28V. I still do not have 28V anywhere in the engine/battery compartment, including the starter. Tom, I think you are on to something when you wrote about the battery cable issues. When this problem 1st occurred the road service company sent out a guy with a 1976 Chev 1/2 ton PU with a battery jumper connection hanging out of the grill. I told him there was no way this was going to get the bus started and I had ordered a commercial truck service truck. He insisted that he could get me started. When it didn't work he called back to his boss who had him remove the battery cables and charge each battery separately. Of course this didn't work either. The second company, with a similar setup but with 4 12V batteries was unable to jump start with the batteries so he jumped it from the starter.

Other than the cable I described above that was apparently mistakenly placed on a - post there is nothing obviously wrong with the cables. Of course there has to be if the batteries are fully charged and connected properly and only check out a 12.8V.

As it stands right now I may not be able to get back on this until Saturday. My whole family, wife, kids, and grandkids are leaving about 4:30am tomorrow for 2 weeks in Puerto Vallarta. Saying everything is in disarray is an understatement!

I am going to get into my Prevost schematics and thoroughly check out the cable configuration on the batteries. I suspect everyone that has helped me on this has wondered if I did something wrong. At this point I think I amy have overlooked the obvious. More to come. Thanks everyone! I'll keep you updated.

You should have a sticker on the inside of the bay door to your chasis batteries showing the wiring diagram for your chasis batteries.

[truk4u]

Mango,

Is that why your batteries were dead when I was at Parliament?:p

[Jon Wehrenberg]

Never saw that aerial attack coming.........

[MangoMike]

That was BOB-00's coach you were trying to start. ;)


mm

[JIM KELLER]

They are both sitting side by side out front on their lot. They seem to be leaning towards each other. We need a dual sale on this deal because one would be very lonely without the other !

[Darl-Wilson]

Darl....the following is a direct quote from post #34....

"Here is the procedure I would use to check this, and why.....

I assume your batteries are up to their desired voltage and are connected according to the Prevost diagram. Obviously this is essential to insure you get the right voltages to the 12V and 24V circuits....."

Perhaps rule number one should be to never leave anyone without Prevost specific experience and knowledge alone with your coach, and after anyone touches your coach verify what they did and if it was right.

To; Jon John, Joe, Tom, all the Jims, and everyone else that helped me solve this problem. It was one battery cable that caused all this starting problem. The center battery of the rear three had the - cable going to the right rear battery - instead of going to the negative on the single forward battery. I am now sure that the 1st company that tried to jump the batteries did this but it could have been the second. I tried watching them but it is a bit difficult getting two people into that space. I also went inside the house and the cab while they were working. Still no excuse for not double checking their work. Yesterday it got 2 degrees above freezing and the snow slowed to a shower so I went out and took pictures of the batteries and of the battery schematic on the door (thanks for pointing that out also) and then retreated to the house and my computer. Upon examination it became very clear that one cable was misplaced. Since it was 15 degrees this morning I waited until the temp got up to 33 and went out and made the change. I checked for the 24V at the shut-off switch and knew it would be OK. Needless to say the coach fired right up.

My only issue right now is why the yellow wire at the negative pole on the inside rear battery sparks when I attach it. It does that regardless of the position of of the shut-off switches. I am going to see if I can find something that identifies that wire and where it goes after leaving the battery. See attached pic. The unattached yellow wire is at the top right of the picture and the offending cable is on the bottom right, before it was moved.

I want to sincerely apologize to all, especially Jon, who spent so many hours helping me solve something that should have been obvious. :oThis was real stupidity on my part and I caused a lot of work that shouldn't have been necessary. The good thing, for me, is that you great POGers helped me find the problem. I guess I thought it couldn't be the cables since they seemed to fit like a jig puzzle. Wrong!! Thanks, Darl:)

[phorner]

Darl, for what it's worth, my Liberty has the very same arrangement with regard to the yellow wires.

Mine were seriously deteriorated, and I have replaced the ends with new connectors.

Glad to hear, even though you went through a lot, that it turned out to be an easy fix after all.

In the future, though, you might pick a better season to play with this stuff...

[Darl-Wilson]

Paul, thanks for the info. Do you know the origin of these yellow wires, specifically the one attached to the negative post on the third battery? (inside, nearest to frame ground)

Mine arcs when I attach it to the post. I haven't been able to get an amp draw reading since my tester quit :mad:but it is not a dead ground, just a slight arc.

I'll take your advice about working on this stuff in better weather. Thanks!

[phorner]

Darl,

On mine, the mysterious yellow wires disappear into what appears to be original equipment wire looms. I was told by Liberty that they power the engine and transmission computers. There may also be something else that is powered by them.

On mine, when I took them off and re-attached them, there was a small "spark", which I kind of expected. This, as far as I know, is considered "normal". I have an appointment next week at Liberty Coach and hopefully I'll get some more information as to their purpose.

The reason I had mine apart in the first place was that my chassis batteries would drain down while parked, and I needed to charge them. I have since installed a 12/24 volt battery charger in the battery bay to resolve this issue. Truk can give you guidance if this is also a concern of yours, since he guided me through the process and I'm very happy with the outcome.

[Jon Wehrenberg]

According to the Prevost wiring diagram #D060873, page #1 those wires go to DDEC power junction #10 in the rear box, and the ECM power connector for the 12 V wires on the negative terminal, and to the transmission feed via CB83, CB19, CB20, CB21 for DDEC3 feed, and junction #5 for transmission feed on the positive side 12 V wires.

Great news about the success Darl. FWIW when we had to be towed because of the fire in our previous bus I sent the first tow driver away because he did not convince me he knew what he is doing. I think if anybody has a problem and the service tech does not instill confidence we are better off to send them on the way.

[Jon Wehrenberg]

I am in the process of doing an article that should help with a basic understanding of the coach electrical systems. With help from Jeff (as in JPJ) and Ben of Parliament Coach the article is being done in a question and answer format. As we were discussing chassis batteries Ben revealed something I have never heard before, nor have I ever seen it in a service bulletin, or in a shop manual. The information Ben provided goes right to the heart of two of the very important threads recently covered here.

As I learned (to my chagrin) and posted previously Prevost does wire from the batteries directly to the rear electrical box without going through the chassis battery disconnect switches. I now think I fully understand why, and I also understand why some coaches experience drained chassis batteries and require a battery charger or maintainer.

First a reminder of what wires bypass the battery disconnect switches. Those wires such as on Paul's, or Truks or any coach in that vintage power circuit breakers 19, 20, and 21 in the rear electrical box. Two relate to the DDEC and one relates to the transmission computer.

Ben indicated that they experienced random instances of dead chassis batteries on coaches being converted and found that it relates to how Detroit Diesel set up their DDEC and/or engine. On some, (Ben estimates 50%) of the coaches the power from the batteries is going to the fuel injector solenoids. On others the circuit was open. This explains why some of us could go months and the batteries were still charged, yet others of us would have dead batteries if an auxiliary charger was not used. Remember, these circuits completely bypass the main battery disconnect and the 12 volt disconnect.

On coaches with this characteristic the battery drain can be stopped by tripping the DDEC circuit breakers. The downside to doing this in addition to it being a pain to have to do, is that some memory logging in the DDEC will be lost, and some items in the volatile memory are erased.

So we can all breathe a little easier thanks to Ben because a problem we here could not quite get our arms around, we now have a logical explanation for why some of us need an auxiliary charger and why those with the problem of battery drainage see that spark when reconnecting the DDEC wires to the battery.

[Darl-Wilson]

Jon, thanks so much for doing this research! I think this may have been what caused my battery problem rather that the ignition being in the accessory position. I am going to install an auxiliary battery charger for sure. What will happen if the circuit breakers are tripped? I was considering the installation of a toggle switch in the line from the battery to the DDEC. Right now I have that wire disconnected from the terminal to avoid having my batteries discharge. Now I am concerned that I may have caused damage to the computer. When I had my electrical problem the batteries were disconnected for over a week and were dead prior to that. Did your research give you information about the consequences if items in the memory logging or the volatile memory are erased? I didn't have any problem running the engine but I didn't drive the coach after finally getting it started. Maybe I should connect my Silverleaf code reader prior to driving the coach.
Again Jon, thanks for all you do!:D

[Jon Wehrenberg]

Darl,

You may wish to discuss this with Prevost engineers (this is beyond service center techs I think) or Detroit Diesel experts, but as Ben explained the load can be removed by tripping the CBs and the only issue is the loss of some memory items. If you have had any codes as indicated by the red or amber warning lights on the dash you may not wish to erase them until a tech can read them, but otherwise I did not get a sense from Ben that there were any other concerns.

Removing power from all of this should do no damage whatsoever because removing power is what happens when you replace batteries or remove them for testing or service.

I see a greater concern over damage if someone connects those circuits to 24 volts.

[win42]

Darl: I would and did on my Royal move those wires to the main 24V disconnect switch. When the switch is off for storage the wires receive no chance to drain. If you add a battery charger, I would suggest a 24V " Battery Tender". I also leave a 12V "Battery Tender" on my house batteries when stored. Sorry I did not get up to Reno to help you, not saying I would have found the proublem, but sometime two heads are better than one. Even an old head. Get your volt meter replaced, they are a must around our busses. I'm also adding an ampmeter to my box.

[Denny]

Jon,
Thanks for the info; now I know why my chassis batteries go dead within a week even with the switches off. I added a 24v Battery Tender and have not had a problem for over a year.

The value of POG is invaluable!!!!

[Jon Wehrenberg]

Harry and Darl......What Harry is doing on his DDEC2 8V92 probably has zero effect on the DDEC memory, however Darl, with DDEC3 may be in the age range when each disconnect of those circuits erases what might be valuable memory logging for a tech.

I think Detroit wanted power to those circuits for that reason and still unclear to me is why some coaches appear to lose the batteries quickly and others are seemingly unaffected. It might be software related to the injector solenoids. don't really know.

[Danss]

Have added the battery tender and everything appears fine . Went to crank bus this am and got all the normal clicks and rpm ind. went over and back but only the battery balance light comes on as normal when starting, but no starter turn over. Went to rear and started engine with no problem. Batteries are fine. Any ideas? Dan

[Jon Wehrenberg]

Dan,

I'd have to dig into the wiring diagrams a little. What year coach?

Gut feel tells me the problem is between one of the rear CBs and the key start which might involve a relay or CB up front. On my old coach I had a bad relay that caused that. It was located in the front box.

[Danss]

It is a 97 . Have not looked at circuit breakers under drivers door, but will do later today. Just seems strange it coincided with hookup of battery tender or maybe it was connected to that.

[Jon Wehrenberg]

Probably unrelated, but i'll look at the wiring diagrams and see what i can see for places to check.

[Danss]

I was mistaken on dash lights---everything lights up as always but no starter. Checked all breakers in rear and under driver to no avail. Where are the large breakers I have heard you speak about that are hard to reset? Thanks for the help!!

[Jon Wehrenberg]

Dan, This is based on a quick look...Check CB18 in the rear box and CB27 in the front. My guess is they are OK but worth checking.

Next to the batteries for the chassis, over the main chassis disconnect switches is a vertical row of big breakers. CB4 and CB7 are power to the front. I suspect they are OK because you have dash instruments / lights. A check for 12 and 24V in the front box will verify they are OK.

Check relays R1 and R2. They might be the problem. Most relays are the same so switch with the same relay used for lights or something unrelated to starting to verify they are OK.

I am going by drawings of the wiring picked at random because from the 96 shell and up Prevost does not differentiate between model years or serial numbers so if my guesses do not make sense that is why.

[Darl-Wilson]

Dan, on my coach those breakers are are on the same panel as the 12V and 24V cut-off switch. Good Luck!

[Ray Davis]

Stupid question here. Dan, you mentioned the bus started from the rear. Are you sure that the remote start switch is back fully in the regular operating position?

Ray

[JIM CHALOUPKA]

Ray, that was a good question. It's all in the details!!!!!!!!! :D

[Danss]

This switch has 3 positions. in the up position I get several clicks and then I can pust starter button and engine cranks. middle position says off and bottom position says normal. I assume it should be in the normal position for starting from dash??? is that right? Dan

[win42]

Dan: My vote would be the round starter relay in the front electrical box under the drivers left window. Mine got lazy and I had to tease it with the ignition switch on and off. If it finally kicks in and the starter works, go to an auto supply that serves the truck industry and get another 24V relay. A spare one on hand would not hurt, because we have others in locations around the coach. If you have help use the electrical tester on the relay as the ignition switch is turned to start. It makes me feel bad you are experiancing so many problems in such a short time. Hang in there they will all get solved soon.

[truk4u]

Dan,

Did anything out of the ordinary happen during the charger installation?

[gmcbuffalo]

Maybe a stupid question but are the oil and antifreeze levels up to where they should be to not shutdown the engine. When my fluids are low the engine will not start from the front only from the rear and then only for 20 to 30 seconds.
GregM

[Jon Wehrenberg]

Harry,

Different relays in the newer shells. I think Dan's coach has the square black ones for the most part. There are few of the round silver ones because they were nothing but trouble.

[Danss]

Nothing happened when hooking up charger as I know of. Will try to check relays today. Engine runs for as long as I want when starting from rear, so fluids are okay. Thanks to everyone for help and suggestions. Dan

[Danss]

Everyone mentions that I should check circuit breakers located above or around 24 and 12 v cutoff switches. Well guess what, I cannot find those but I do have a row of vertical red buttons that are fuses are breakers????
Help, Dan

[Jon Wehrenberg]

Dan, the circuit breakers are brown or black plasitc devices with a round red button. You can trip and reset them. I think the only one applicable since you have the full dash would be CB18 in the rear box. You would see the indicator popped out

I assume you checked the relays.

It could be in the key switch also, but the other stuff does not require any disassembly, other than moving a relay or two.

[lewpopp]

Betcha it's the solonoid outside under the driver.

[Danss]

Found and reset circuit breakers, swapped relays, reset all small circuit breakers, walked around bus several times uttering unprintable phrases, all to no avail. Taking His Majesty to a bus repair facility Thurs. Will post outcome. Thanks again, Dan

[Jon Wehrenberg]

Dan,

Hate to see you having this trouble. If you want to get into the nitty gritty and work backwards you ahould have power to wire 84 in the front junction box when the key is in the start position. If the coach will not front start, that is the last point in the front box before going to the front/rear start selector switch.

I assume you checked relays 1 and 2, also check relay 6 and CB10. It could be as simple as a bad ignition switch.

[phorner]

Well, after my visit to Liberty Coach last week, they did confirm that I had a bad alternator which was giving me the often fluctuating voltages while the bus was running.

So, after a quick alternator replacement, all is well and the voltage at the house batteries, while the engine is running, is fine. Janice supervised all the maintenance work as I was stuck at jury duty during our stay at Liberty.

As a side note, they checked my chassis battery wiring and confirmed that all was normal with respect to the "mystery yellow wires" that was the topic of so much discussion a while back.

And Truk, they gave us high marks for the work on the chassis battery wiring and installation of the battery charger so, if we are ever in need of a career changing out chassis batteries, they have a spot for us.....

[truk4u]

Wow, you mean Janice got us an atta-boy while at Liberty?:D

[phorner]

Yeah, Truk. Somehow, Janice seems to get a lot more personal attention from the service tech's than I can muster.

[truk4u]

Look in the mirror Paul and turn sideways, now you know!:D