Low Voltage Warning

[jslupsky]

I have a 2008 Itasca Meridian on a Frieghtliner Chassis. The other day I received a "Low Voltage" warning on the display as I was driving. I looked at the analog gage on the instrument cluster and all was normal where it usually is, about 14 V. Later in the trip as I was slowing on an exit ramp, all of the instrument lights started flashing, and the "Check Engine" warning came up in the display, as well as the symbol on the dash.

I got the coach home, and since it had never had the chassis batteries changed, I changed both of them. I then took the coach to Cummins to check it out, and they could not find anything, other than to say that changing the batteries likely fixed the problem.

I brought it home, and while parking it, another warning light came up. I got out to check if the garage door would close, and when I got back in, I noticed the warning "Auto Idle". And then underneath the warning was the system voltage displayed as 13.8V and then Theshold at 13.4V. After moving the coach forward, the warning went out. I called Cummins and they said this is an OEM issue. I called Freightliner and they said to check for loose connections at the alternator, starter, battery. I checked and all seemed good. I also started the unit and turned on all the lights, wiper, AC, et, and the digital voltage display was 13.8V.

Is it possible that the voltage regulator in the alternator is working then not working? I would think it either works or it does not.

And so if the alternator is fried, how in the world would I ever get this thing out? This coach is not easy to work on, and I am not even sure going in under the bed would allow access to remove the alternator.

Any help would be appreciated. Thanks.

[dickandlois]

jslupsky, Welcome to the FMCA forum !

The issues and items you posted, along with the problem being intermittent sounds like a voltage regulator problem.

You might want to take a look at this thread where I addressed a continuing alternator problem. See if anything looks or acts the same.

http://community.fmca.com/topic/3930-engine-alternator-issues/?hl=%2Balternator+%2Bheat+%2Bproblem

Rich.

[jslupsky]

Thanks Rich. Wow! Can't say those things are happening to me.

Yesterday I forgot to mention that the coach is equipped with a Cummins ISB 350 that is mounted f/b rather than side to side.

It also has basement air so I have no access from the sides to get at anything.

Do you think dust could damage the alternator? We were at a campground a July where the road in and out was fine dust. I ended up sucking a lot of the dust up into the engine area and blowing it out the rad.

If the issue is the alternator, getting to it will be a challenge. Any idea where I might find a shop manual that explains what I need to remove to get to the alternator? I thought about Freightliner but when this was just a chassis there was all kinds of access; they probably have no control over what the coach builder does with it. Unless I missed something Winnebago does not have a shop manual.

The day this first happened we had the generator running and it was not overly hot outside (it was overcast and maybe 86 or so). Wouldn't the generator also be charging the batteries? On Friday when I had the Auto Idle alert the generator was not running.

In reading the information you sent I take it the voltage regulator can work the way it is supposed to sometimes and then not work other times?

Thanks

John

[wolfe10]

John,

You really need to determine if this is really a voltage issue or a gauge issue.

Rig up voltmeter to the B+ terminal of the alternator OR if easier to the B+ (alternator in) terminal of your battery isolator (both will read the same).

Drive and see if the voltage really varies, or if it a gauge issue.

And, yes, indirectly the generator will charge the batteries-- certainly the house bank. It does this by powering your inverter/charger.

Armed with actual voltage readings, Freightliner is where you need to go for answers to what/where to check.

[jslupsky]

Thanks. I also have a digital display of voltage in addition to the gauge. I will monitor the voltage and see what it does ( I have it as one of the three things you can keep on the display at all times).

Thanks

[dickandlois]

John, Regarding you question about the alternator regulator being intermittent. The answer is yes and it tends to show up when the ambient temperatures get to 85 deg. and up. Poor air flow and the higher temperatures in the engine compartment does not help.

Brett mentioned using a meter to monitor your 12 volt supply voltage and if your regulator is going bad, a meter can display longer term voltage changes.

The issue of noise pulses riding on the 12 volt supply is only detected when using an oscilloscope and they are not common at service centers, then if it is temperature related bad regulators can function just fine when cool.

I have played with the alternators supplied from off shore and there quality control is weak.

Still using an off shore unit, but install Delco Regulators now on 2 different model alternators to see if indeed this helps increase the trouble free window.

When we have tested the units in the rebuild shop under heavy load conditions, we have not been able to confirm or find a difference.

That kind of makes our coach a test bed so I carry a spare and work at monitoring ambient temperatures while driving.

With your issue being intermittent. One item to check is all the ground connections for the batteries,Engine and alternator. Loose or corroded connections are one key area that can cause the problem you are experiencing.

Note. With the addition of the air pickup and ducting air directly to the alternator; the air temperatures under the engine cover is definitely lower.

I now need to invest in a better remote temperature monitoring system to log thermal swings if possible. Not the normal garden variety price tag on them ether!!

Rich.

[geodaun]

John,

I have been having the exact same problem on my 2005 Fleetwood Discovery 35M, Cat 330 in a Freightliner Chassis.

Started shortly after July 4th in fairly hot (90's) temps.

First, I noticed a warning light on the dash, and the info center said the same thing as yours (warning "Auto Idle". And then underneath the warning was the system voltage displayed as 13.8V and then Threshold at 13.4V.).

You noted that you moved the coach and it stopped, I bumped the brake trying to read the info center, that is located low on the dash and hard to read, and the idle dropped to normal and the light went out. All seemed OK at this point.

Tap the brake which will drop the idle speed and the auto idle and too much voltage should stop.

I have had my coach for a year and this just suddenly started happing each time I started the coach after I had been boon docking for a few days. It did it 3 times with no other side effects, it seemed fine.

Then, I was driving on hwy (395) and a light came on "Low Voltage" 11.8V. I looked at my Volt Gauge on the dash and sure enough it was showing discharge. Slightly Left of Center. I was right in the middle of a big climb and there was no where to pull over. So I just reached over and started the Generator and decided to wait until I got to Bridgeport, CA to pull over and look at it. Within 3 to 5 minutes the meter on the dash began to show charge, needle slightly to the right of center. ( no number on my gauge just marks.)

Pulled over and shut everything off. Got out my multi meter and the battery showed 12.6V with nothing running and only minor load.

Started the engine and retested, 12.1V to 12.2V with engine running.

Started the Gen and initially it showed 21.1V but, as has been pointed out to me on another Discovery Owners Forum by Gary Osburn, The alternator charges the Chassis first and then moves to the house, and the gen charges the house first and moves to the chassis. Sure enough, since the house bats were full, within a few minutes the current at the batteries hit 13.4.

Not to drag this out to long, it was Sunday, in a small town and NAPA had just closed for the weekend… I pressed on using the Generator. I drove it into Carson City and parked in a CG with Full HUs.

Put it on the DOAI Forum and it seemed clear that all agreed it was a bad alternator. Called Cat, they wanted $750 just for the part. Hung up and called Freightliner, they wanted $450. Just happened that the lady next to me in the RV park had a Brother in the auto parts business and he sold me one for $350. Had it shipped to my sisters to pick up.

​Picked it up and tossed it in a bin and drove to Colorado to a shop to have it put on, as I had to get there for other commitments and it was to HOT in Clear Lake CA to do it myself in my sisters front yard.

​It was installed and we initially tested the batteries and they showed 13.4 … Success or so I thought. Paid the bill and off I went… Oh wait the gauge shows discharge again… U turn back to shop… 12.2 T THE BATTERIES AGAIN!!!

Having spent 3 days in the shop getting a bunch of stuff done and no showers plus hot hot hot, decided to go to my campground and think about it.

Then this morning, your post!

Let's keep each other up to date on this.

I did some more research this morning and decided I need to do more testing.

Pull the floors and check the output on the back of the alternator.

If it is producing 13V plus check the continuity to the battery to see if the charge is getting to the batteries throughout the wire.

Could be a bad/shorted wire or a blown fuse or fusible link.

Then do some more thinking and discussing.

I hope it is not the issues Rich has had. Ouch!

George Daunis

05 Fleetwood Discovery 35M

Cat 330 in a Freightliner chassis.

[jslupsky]

George

Sounds like we have the same issue. Although in reverse since I had the "Low Voltage" show up first followed by "Auto Idle" later. I did check another forum and see that the "Auto Idle" appears to be a common issue. In my case I' am wondering if I "fixed" the problem when I replaced the chassis batteries - then perhaps they did not have a full charge on them and maybe they are low and need a charge - which is why the auto idle came up maybe?

I will be moving again at the end of the month so will know if that was what it was.

I did my best to find all the bat + connections throughout the coach and they all seem tight. I am going to check some of the grounds and see if maybe some of those are loose or maybe corroded.

I will let you know what I find.

John

[geodaun]

John,

I have a family reunion this week so I will not have time to do much, but I will stay in touch and let you know if I find any new information.

George

[dickandlois]

John,

I had to look at some older notes, regarding when the Check engine lights where coming on in our coach.

The ECM's appear to get fussy when the alternator voltage goes above 14.2 voles + or - a small percentage and when the voltage drops below the 11.5 to 12 volt range.

Most of my issues have been noise related and the voltage levels going to high.

Rich.

[jslupsky]

All

Spent the last few weeks looking at wires in my coach and other discussion forums on this subject. Here is what I have done -some of this stuff has nothing directly to do with the problem - however indirectly I think it does.

1). Two years ago I replaced my house batteries with AGM's. When I did this I noticed that the cables where corroded at the lug to wire connection. I was meaning to replace them. I was hunting for someone that made cables like the ones that the chassis builder uses - all sealed. I never did find a cable like those so I finally made my own last week and used heat shrink tubing to seal the lug to the wire. I replaced all the house battery cables as well as the connection to the coach ground (That is the indirect part).

2). There is a lot of stuff out there regarding the "Battery Low Voltage". Seems like this happens to a lot of Freightliners.

As mentioned previously I also just replaced the two Alliance chassis batteries with two new sealed batteries from Freightliner. (Those cables are in great shape because they are completly sealed at the battery).

On Friday I started a 200 mile trip and the low voltage came on 3 or 4 times for maybe the first hour and a half. I noted the voltage from the alternator during the trip as 13.5 to 13.9. Basically the voltage would start out at 13.9 and as I drove it would decrease a little bit to settle out at 13.5 to 13.6 or so.

I did another 200 miles today (102 heat) and the warning did not come on once. I am going to hope that the new batteries where not charged all the way and after driving (and being plugged in for a couple days) they are now fully charged. Perhaps this issue is fixed?

I am also going to change out a ground to the chassis - I must admit - last year when I was under the coach doing some maintenance I noticed a ground that did not look so good. With all that has been going on I think I am going to go ahead and replace it. These ground connections I think tend to be forgotten about due to the location of them - while the house battery ground is in sight of the batteries, the chassis one is underneath the coach. I will crawl back under once I get some time and try and find the wire I noticed.

If something else comes up or I discover anything I will let you know.

[wildebill308]

Well lets hope you got that fixed.

Bill

[patwhite]

I had the same problem on my 2003 Fleetwood Providence on a Frieghtliner chassis with a Cat engine. Luckily I could charge the main batteries with the generator while driving. I first called Fleetwood and received 20 pages of electrical information. I spent a day checking the operation of the aux start/charge switch. It worked as described. Checked all related fuses, and battery isolation switches and CB. Learned a lot that day. Eventually I had to remove the closet floor and get a reading off the alternator as Brett suggested. 12.2 volts - same as the main battery.

Asked a friend where to take it for alternator work and got good advice. After talking with ACK electric in Des Moines several times, and sending a picture of the alternator, we had a plan. Picked up a new, more powerful alternator (DelcoRemy 24SI HP) and advice on who to install it. Ended up at Pro Diesel in Des Moines and had it changed out in two days, 3 hours shop time. New alternator working perfectly. I also had the air cleaner replaced while they were working in the area.

Overall a pleasant experience and I learned much about RV electrics.

Pat

[adrainey]

Just a quick post as everyone seems to have covered most things. 2005 Freightliner diesel. Similar problem.

Diagnosed that alt fine but solenoid that controls alt charge between coach and chassis batteries bad. Alt not charging batteries as result. When sat for period of time constant drain discharged batteries and without shore power or generator batteries never charged. New $350 solenoid and problem solved.

dudley

[jslupsky]

Well, the problem is back.  Since this issue first started I have had the electronic display on the dashboard set to show the voltage constantly.  The voltage displayed runs between 13.6V to 13.9V.  Just the other day (about 5 miles out of Forest City, Iowa), having been on the road for quite a few hours, the alarm bells went off and "Low Voltage" was back up on the display.  The alarm went away after a few seconds, and I started watching the display. What I noticed was that the voltage instead of being stable as noted above would occasionally drop as low as 10V and then return to normal values. I am not exactly sure why I was able to see the 10V but maybe in order for the display to indicate Low Voltage it needs to stay low for a certain period of time.   Over the course of a couple of miles this problem was evident - and then just as quickly as it came about, it stopped and things went back to normal.

The roads are good and smooth, so no bumping going on at the time.

I have read some old posts on another site about a 125A circuit breaker located behind the wheel on the drivers side. I can't say that I have noticed one of those, but as I recall there are a couple of solenoids in that compartment as well as the trickle charger for the batteries. I think one of the solenoids is for the house batteries (activated with a switch inside the coach to turn the power on/off) and not exactly sure what the other one is for - maybe the starter.  I could open up the panel and look around in it but before I went messing around in there I did I wanted to ask if anyone out there has had this issue and it was this bad circuit breaker. It is hard for me to believe that everything can work fine for thousands of miles - then act up for a few miles- then go back to behaving normal. Anybody got any ideas?

[dickandlois]

John, What is the outside temperature when the voltage starts to drop?

 You driving a Diesel pusher. Is the alternator located on the same side of the engine as the Exhaust system and turbo charger?

Has the alternator ever been changed?

I have a feeling that the problem come up around the middle of the day !

Rich.

 

[lmsooter]

13 minutes ago, jslupsky said:

Well, the problem is back.  Since this issue first started I have had the electronic display on the dashboard set to show the voltage constantly.  The voltage displayed runs between 13.6V to 13.9V.  Just the other day (about 5 miles out of Forest City, Iowa), having been on the road for quite a few hours, the alarm bells went off and "Low Voltage" was back up on the display.  The alarm went away after a few seconds, and I started watching the display. What I noticed was that the voltage instead of being stable as noted above would occasionally drop as low as 10V and then return to normal values. I am not exactly sure why I was able to see the 10V but maybe in order for the display to indicate Low Voltage it needs to stay low for a certain period of time.   Over the course of a couple of miles this problem was evident - and then just as quickly as it came about, it stopped and things went back to normal.

The roads are good and smooth, so no bumping going on at the time.

I have read some old posts on another site about a 125A circuit breaker located behind the wheel on the drivers side. I can't say that I have noticed one of those, but as I recall there are a couple of solenoids in that compartment as well as the trickle charger for the batteries. I think one of the solenoids is for the house batteries (activated with a switch inside the coach to turn the power on/off) and not exactly sure what the other one is for - maybe the starter.  I could open up the panel and look around in it but before I went messing around in there I did I wanted to ask if anyone out there has had this issue and it was this bad circuit breaker. It is hard for me to believe that everything can work fine for thousands of miles - then act up for a few miles- then go back to behaving normal. Anybody got any ideas?

I had the problem last year on my coach.  I thought I might have to replace the alternator.  When I started checking to see what I needed to do to remove the alternator, I found a  loose wire connected to the alternator.  I labeled and removed all wires and cleaned all terminals.  That has been a little over a year (and 5,000 miles) ago and it has never happened again.

[jslupsky]

Rich

The coach is a pusher and the alternator is on the same side as the turbo and exhaust. It was later in the day and last Sunday I think it was probably low 90's and humid. 

The alternator has never been changed. When this started last year I replaced the coach batteries and thought this was solved. Probably put a couple thousand miles on since then - course that was later on in the year and a bit cooler. 

I do believe this is temperature related.  

........and if the alternator was actually mounted in a spot where I could actually touch it -probably going to have to see if it can be accessed from under the bed - I want to make darn sure this is the issue before I go down that road......

As noted last year, I also had this "Auto Idle" issue. That has gone away with the new batteries (when I would start the coach - it would always go into high idle - which I now realize was because the batteries were shot). Auto Idle can also kick in by itself if engine is at low idle but needs the extra RPM to get the alternator going. 

As I noted, I have logged a few thousand miles and have watched the voltage like a hawk. If the alternator was bad it should be non functioning all the time - or is my logic incorrect here and the heat has some effect?

John

[dickandlois]

John, I fought alternator failures for years. Changed to higher amperage units, installed different internal voltage regulators and they would work for 18 months to 2 years and start to fail.

They mechanical parts have never failed, but the regulators start to breakdown because of heat. I always had a spare one when on the road. 

The alternator on Our coach is not hard to get to. So When it would start to act up, I just reached in to the engine compartment and disabled the energizer circuit. Then I started the generator and used it to power the inverter / charger to keep supplying power to the batteries. This worked fine. One morning I reconnected the alternator energizer circuit  and started off on the next leg of our trip. The Alternator functioned fine unit the ambient outside temperature got to 85 to 90 degrees and it started acting up. Went back to using the generator to power the coach and chassis 12 volts the rest of the trip.

Once at home it was time to find the part that was failing and why ! Removed to voltage regulator and inspected it very closely, Long story, but this is what happens when the alternators fail when hot and work fine again when they cool off !!

THE regulator diodes fail do to a process call thermal avalanche point. They fail to maintain proper voltage levels because when the regulator is heated current flow is interrupted at say 13.5 volts, and the voltage drops unit it reaches a lower voltage point where the current flow settles at say 10.0 volts and stays there, but that level voltage and lower current output is well below what the engine systems require. Let things cool down and you can run again unit things heat up. Self healing to a point !!!!

Rich. 

Note- I added a duct-work cooling system to  the coach to keep the air temperature around the alternators cooler and all has been well for now. Pictures in the Photo gallery section of the Forum.

[jslupsky]

Thanks Rich. I guess I have some work to do.  

[jslupsky]

Well I thought I would update everyone - on what I hope has fixed this once and for all.  

So as it turns out the problem became much worse. Had all the gauges going squirrelly - 0 psi oil, check engine, check transmission, and then dead on the side of the road. I could crank but no start.  Towed coach to Freightliner.  They had it for 2 weeks.  Evidently they were taking the engine computer out to send over to Cummins and noticed a spark. On further investigation they found that a ground connection ( apparently there is a braided ground strap) had only a few strands left on it. (I would have thought the engine would ground through the mounting bolts).  

They replaced it and one other ground.  I sure hope this has fixed that - 2 weeks at the Freightliner spa don't come cheap.  Freightliner "threw in the new wire" for free. ?

[dickandlois]

On 8/2/2016 at 11:18 PM, jslupsky said:

Well I thought I would update everyone - on what I hope has fixed this once and for all.  

So as it turns out the problem became much worse. Had all the gauges going squirrelly - 0 psi oil, check engine, check transmission, and then dead on the side of the road. I could crank but no start.  Towed coach to Freightliner.  They had it for 2 weeks.  Evidently they were taking the engine computer out to send over to Cummins and noticed a spark. On further investigation they found that a ground connection ( apparently there is a braided ground strap) had only a few strands left on it. (I would have thought the engine would ground through the mounting bolts).  

They replaced it and one other ground.  I sure hope this has fixed that - 2 weeks at the Freightliner spa don't come cheap.  Freightliner "threw in the new wire" for free. ?

John, If the engine bolts went directly between the engine and chassis, the noise level would go up and you would not need a masseuse. Those braided ground cables do fail when exposed to road salt. Even when the roads dry off the dust can build up on them and when it gets wet the chemical reaction will eat them up.

Keep a pressure washer around to wash off the engine, but make sure you cover things up well inside the coach if the doghouse cover is open ! 

Good to hear you are back up an running !

Rich.