Alternator Bad???

[dca81]

Yesterday wife and I started on a trip to Iowa to an see an Indy-car race. We took I-76 east out of Denver which is an extraordinarily rough road. So rough that I had to stop after about a 100 miles and put my mirror arms back in place because they had vibrated loose. When I got back into the motor home I had an intermittent alternator light coming on. Could not find a local repair shop so headed back home (there goes $500 worth of tickets and camping paid for the weekend). The alternator light continued to come on/off intermittently on the way home. I started the generator to charge the battery and turned off all the 12 v. stuff. The Aladdin System would show 12.1 to 11.9 volts on engine battery (Engine/Trans status mode), then suddenly go to 13+ volts. Alternator light on dash did not respond as quickly as the Aladdin but would come on loosely correlated with the Aladdin readings. Under the Aladdin system I could watch the coach batteries (Coach electrical status mode) slowly drain down on voltage. (12.5 lowest reading). At 12.7 volts I got a check engine light flash on (3) times. Then the alternator would seem to kick on and the light would go off at 12.9 volts. Figured this was a warning that I was not getting enough voltage and these units will shut down to protect the ECM at a certain voltage.
So the point is do I need to replace the alternator, or could it be a wire has vibrated loose. Does an alternator go on and off intermittently when it is going out, or is that indicative of a loose wire/cable? IF it is a alternator does anyone readily know the part required(2004 Windsor ISL) and a good source? BTW, started it this morning and everything seems fine (no alternator light, and engine battery was 13.4 v after starting...however only 12.1 before starting.
Thanks for you response.
Bob

[Dynasty_09]

I would suggest that you check if your alternator is outputting more than 13 volts at the alternator even if the Aladin shows l'ESS than that.
If so, I would suspect pitted contacts in the big Boy...

[dca81]

OK, did not think of that!!! I thought the big boy only impacted the house batteries/current. But the current lost indicated on the Aladdin did not correlate directly to the alternator light on the dash...which confused me ( see current drop on Alladdin with no alternator light). Thanks for the suggestion.
Bob

[dca81]

The plot thickens...I went out to locate my Big Boy isolator. I assumed it was the battery isolator solenoid located on the electrical panel. Much to my surprise my isolator is a Trombetta 114-1211-010. This is a new to me RV in January ...so I assume (again) that the Big Boy isolator has been replaced with a Trombetta battery isolator. Or is the Big Boy located elsewhere (not on electrical panel) on a 2004 Monaco Windsor?
Just as aside its hard to accept that this inexpensive ($59 on Amazon) and easy get to part is the cause of cancelling a relatively expensive weekend. Oh well not the most expensive lesson my ignorance has costs me. But I really would have liked to see that race.

[CountryB]

That Trombeta solenoid part number you gave is not a "battery isolater" solenoid like the Big Boy. At least that's not what it is intended for. It is just a continuous duty solenoid (like the Salesman's Switch).

Trometta does make a Battery Isolater-separator https://www.trombetta.com/wp-content...l_r15proof.pdf

Most alternators have a built in regulator - so you should test output at the alternator battery output terminal (and if you have a Duvac style battery alternator, then you need to be sure the Alternator is reading voltage at it's Sense terminal).

If you have a "Big-Boy style isolater system, and need a new alternator, a Delco 24SI or 28SI is a good choice.

[dca81]

Well not sure what I should due about the trombetta? So should I change it? What is the consequence of leaving it as is? Also, I am confused about testing the alternator. As previously indicated the alternator seem to be kicking on and off ever since I first saw the alternator light (I drove it over 100 miles home). When I started it this morning it is currently working (per voltage reading on Aladdin and no alternator light). Therefore, intuitively if I test voltage at the alternator I will get a reading for adequate voltage. I assume the alternator has an internal voltage regulator that is probably kicking on and off .
Obviously I am doing a lot of assuming in this thread. In the way of background professionally I was an accountant/auditor. So I am not familiar with Mr Tesla's theories or the functioning of various electrical parts. However, I have a modest collection of old cars I routinely play with and maintain. So changed a few alternators and generators. Even rebuilt a few 1200cc VW motors for my FV. So, if I can figure out the belt tension system on this ISL I can probably take the alternator out and put it back with the wires in the same place (I assume again). So could the trombetta switch cause the engine alternator light? And what is impact of just replacing with the same solenoid if it is bad?
I am a bit confused but really do appreciate the assistance.
thanks
Bob

[CountryB]

Can you post a picture of the components in the Rear Run Bay (Battery area)? It may help identify your setup and what parts are installed.

[twinboat]

If you are having chassis battery charging issues, with the engine running, its not the Big Boy, Trombretta or any isolation solenoid system.

The engine alternator is directly connected to the chassis battery and its primary job is to maintain voltage to the chassis systems.

The isolation system is added on to charge the house batteries only when the chassis battery is being satisfied.

If the charging system is failing, it could cause the isolation system to connect and disconnect causing house battery fluctuations but if the chassis battery voltage is fluctuating its the akternator or its wiring.

[Sbrownstein]

TwinBoat has a point. If you have a dynamic system with an isolation solenoid and a weak or failing alternator, the isolation system will connect the house above a certain voltage which may then be dragging the alternator output down below the trip point and then disconnecting the house again. If it is a dynamic system, unfortunately there is no easy way to disconnect it unless you pull the low current leads off the isolation relay solenoid coil.

[dca81]

OK, thanks for the reply. If I understand this correctly if as in my case the motor is running and the alternator light comes on and voltage drops then it is a malfunctioning alternator or loose wire, not a problem with the battery isolator. However, I am still confused about the impact of using a "continuous solenoid" versus a battery disconnect solenoid. My assumption (ahhh that word again) is that the continuous solenoid is charging both the house and chassis batteries when the key is turned on and the voltage of the combined batteries fall below fall below a certain voltage? Actually that last statement is much more a swag then an assumption.
Thanks
Bob

[twinboat]

In many cases, the continuous duty solenoid is being controlled by a voltage sensing controller.

That device monitors both battery bank voltages and decides when to connect the 2 battery banks.

If the combined battery bank voltage drops below what the chassis needs, the device will disconnect the house battery so house loads don't continue to discharge the chassis battery.

[Sbrownstein]

Actually the solenoid engages when the voltage is above a certain level indicating that something is charging one battery and the other can be connected in parallel to be charged as well. Depending on your coach it might work with the alternator charging the chassis and the house and the converter charging the other way as well. Active systems constantly measure voltages and only connect the batteries when the voltage goes above a certain trip point, like 13 volts, which a battery by itself cannot hit.

[8.3Oilbuner]

Good afternoon Bob; Interesting problem you have posted about. I just want to let you know of what experience I have had with the alt. light on my 2000 and new to me 2001 Windsor. First, I do not have the Aladdin System. I do have a Silver leaf system to view what is happening with the engine Ecm. On both coaches when both sets of batteries, chassis and house, are fully charged and I have no loads on the system, wipers, dash heating blower, headlights and etc. the alt. light will start flashing. To get the light to go out I have to add a small load to the system. I just turn the dash blower to the second speed from low and the light always goes out. Also have noticed that if you are checking voltages at an engine idle, 600 RPM, voltages are 13.2V or less sometimes. If I just bring the engine up to between 800 to 1000 RPM I can watch the voltage on the Silver Leaf go from 13.2V up to 13.9 to 14.0V. It seems once the alt. senses that an increase in a load, everything seems normal. No alt. light flashing and a steady voltage of 13.9 to 14.0V on the Silver Leaf. Both the 2000 and the 2001 have acted exactly the same in characteristics. It would have been interesting at the time you saw the flashing alt. light and applied a good load to your system to see if the alt. light would have gone off and voltages would have come up in value. This is just my experience and thought I would pass the info along. Others here have provided you with great info. I would just note that if you are checking the alt. for voltage output you might need to increase the engine RPM's to see if the alt. is providing the proper voltage. Hope this info helps and good luck!

[Ivylog]

Not trying to be a Smart Ass. Is the alternator light red or orange? My wife (DW) knows to pull over and call me if a red light comes on while driving, otherwise keep going within reason. Instead of turning around I would have started my generator and blocked the boost switch on...charging both sets of batteries. Yes, I know a BigBoy (if you have one) is not continuous duty but I’ve done this for several hours at a time as you do not have to run the generator all the time.

I would have the DW turn the boost switch on/off as you listen at the back...it will have large red wires going to it. The alternator light often comes on when you run both the generator and the engine. If it gets down to the alternator being the problem, have it rebuilt as often a new one will give you some other problems, like no tack.