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Preventing DUVAC alternator problems


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Thank you for the very detailed information. 

Your original system is very close to my 99.

My battery switches are by the batteries. 

The subject you addressed so completely is a topic almost weekly. 

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On my project list. When I switch out my inverter, I plan to switch house batteries to Lithium.  The charging system kinda becomes  void as the lithium’s suck a lot of amps and can overheat the Alternator. Also cannot not “combine” the house and chassis batteries anymore, so that can come out as you did. 
I will be relocating house batteries as well. 
 

I’ll mark this thread as reference, I appreciate you taking the time to post. 

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I like many have seen this topic several times.  My coach is a 95 and it seems all those parts are in the back, mounted on the firewall.  I replaced my alternator about 9 nine years ago and took it to a alternator shop to get it working.  I was on a trip when it went out, and replaced it while camping, but never got it working properly.  The alternator shop got it working but he said he could not get the alternator to "turn off".  Said it was constantly drawing power and would run the chassis batteries down if I didn't install a switch.  I did not install a switch, just seemed like would be something I'd forget to turn back on... so I just keep a trickle charger on the batteries when parked.  The post above has me thinking that perhaps I could replace my isolation box with the ML ACR and could fix my constantly "on" alternator???  BTW, I had the old alternator rebuilt and kept the what looked like to me to be a Ford regulator, in case I ever needed it.  Have had no issues so far.  Anyone have a idea about this, feel free to advise.  Jim 

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1 hour ago, JDCrow said:

On my project list. When I switch out my inverter, I plan to switch house batteries to Lithium.  The charging system kinda becomes  void as the lithium’s suck a lot of amps and can overheat the Alternator. Also cannot not “combine” the house and chassis batteries anymore, so that can come out as you did. 
I will be relocating house batteries as well. 
 

I’ll mark this thread as reference, I appreciate you taking the time to post. 

You probably already know about the Li-BIM 225 offered by Precision Circuits, Inc.  If not, take a look.  It interrupts charging to the lithium batteries on a time-based schedule.

Li-BIM for Lithium batteries.jpg

28 minutes ago, Jim Bob said:

I like many have seen this topic several times.  My coach is a 95 and it seems all those parts are in the back, mounted on the firewall.  I replaced my alternator about 9 nine years ago and took it to a alternator shop to get it working.  I was on a trip when it went out, and replaced it while camping, but never got it working properly.  The alternator shop got it working but he said he could not get the alternator to "turn off".  Said it was constantly drawing power and would run the chassis batteries down if I didn't install a switch.  I did not install a switch, just seemed like would be something I'd forget to turn back on... so I just keep a trickle charger on the batteries when parked.  The post above has me thinking that perhaps I could replace my isolation box with the ML ACR and could fix my constantly "on" alternator???  BTW, I had the old alternator rebuilt and kept the what looked like to me to be a Ford regulator, in case I ever needed it.  Have had no issues so far.  Anyone have a idea about this, feel free to advise.  Jim 

Sorry, Jim.  I can't remember much about the DUVAC I had that was equipped with an external regulator.  But it sounds like the "Excite" terminal of the alternator is connected to an "always-on" source.  The "Excite" terminal needs to be energized by an ignition-switched circuit.  I am not sure that installing the ML-ARC would fix that.  Check the "Excite" terminal on the alternator to see if it is energized even when the engine is not running.

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Great post!

John could I send you an email in regards to another topic ( having problems with our 1953  60 series John Deere) I do not want to annoy anyone on our Monaco site, do you have another email address that I can ask the question (if you don't mind)

Thanks 

Wayne 

1999 Signature Caesar 

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13 minutes ago, wayne.cerven@gmail.com said:

Great post!

John could I send you an email in regards to another topic ( having problems with our 1953  60 series John Deere) I do not want to annoy anyone on our Monaco site, do you have another email address that I can ask the question (if you don't mind)

Thanks 

Wayne 

1999 Signature Caesar 

Soillife7@gmail.com 

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Thanks for a very detailed explanation and the implications of a failure on the road.

Some questions:

  1. How would I determine if the alternator is DUVAC type?
  2. Were the DUVAC alternators used only on the DP coaches or also on the gas (I have a W24 Workhorse chassis)?
  3. Do you have any idea when Monaco stopped using DUVAC alternators?

 

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43 minutes ago, Martinvz said:

Thanks for a very detailed explanation and the implications of a failure on the road.

Some questions:

  1. How would I determine if the alternator is DUVAC type?
  2. Were the DUVAC alternators used only on the DP coaches or also on the gas (I have a W24 Workhorse chassis)?
  3. Do you have any idea when Monaco stopped using DUVAC alternators?

 

Martin,

1) It's not super-easy to identify a DUVAC from a non-DUVAC alternator from the pulley side of the alternator.  It requires access to the REAR of your alternator. Conventional, modern alternators MAY have only ONE or TWO terminals--a B+ (battery) terminal from which the alternator charges ALL connected loads, and (possibly) another terminal that is ignition-key-activated.  For "self-excited" alternators (most modern types), there may be only ONE terminal--the heavy cable going to the positive post of whatever battery it is charging.  (NOTE that there may be other terminals, such as a tachometer output, but these do not affect the alternator's ability to charge batteries.)  Ignition-key-activated terminals are GENERALLY for setups that are NOT self-energizing. 

If you have a SSI (Solid State Isolator), you almost certainly have some sort of DUVAC alternator, as it MUST sense voltage AT THE BATTERY POSITIVE terminal, and NOT at its output terminal.  The SSI is commonly a large (4" x 12") BLUE (never seen another color, although surely there could be others) device with (3) VERY HEAVY battery cables attached and heat-dissipating fins.

2) I cannot answer whether the DUVAC alternators were only present on the DP coaches.  They could have been built either with, or without.  For any coach 20 years old or so having two battery banks (House and Chassis), there MUST have been some method to prevent having your House loads drain your Chassis batteries.  For Workhorse chassis models, there may have been only one battery bank...I'm guessing.  In that case, there would be no need for a DUVAC alternator.  Again, the SSI was only necessary to isolate chassis (engine starting) batteries from House batteries (powering lights, fans, AC controllers, furnace controllers, water heater controllers (switching between AC power and propane) which powered all your 12VDC loads.

3) Perhaps someone else can chime in who knows the answer to when Monaco stopped using SSI's.  I'm GUESSING (do not KNOW) that it would have been about 2003 - 2004.  Bob Nodine owns a coach of that vintage.  Perhaps he will answer.

To try to explain why the troublesome DUVAC system ever existed--at the time they were used (20+ years ago), the SSI was seen as "state of the art" in charging systems that charged multiple battery banks.  At that time, separating battery banks (when no charging voltage was present) MUST be accomplished by SOME method.  Again, at the time, SSI's were seen as simple, rugged devices that accomplished their function without moving parts, complex circuitry or USER INTERVENTION.  BUT, there was a voltage-drop across the SSI of about 0.7VDC.  Although that seems quite small, it is very significant in whether your batteries ever reach fully charged condition in a reasonable time.  Our dear departed friend, Bill Groves, was very aware of that, and often spoke about how to remedy the situation.  Chuck B, who was in charge of HUGE battery banks for the phone system, would probably tell you the same thing--just tenths of a volt divide rapid, full charging from batteries that are chronically under-charged.

Again, I apologize for a lengthy post, but the details of fully and efficiently charging a large battery bank are often misunderstood.  Settings on the charge controller of either Trace, Xantrex or Magnum are almost universally left at the factory default settings, and that short-changes their capabilities significantly.

Once again, apologies for such a long post.  Safe travels...and trouble-free travels.

Respectfully, Van

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Literally was researching this topic this week. Amazing write up and explanation. Probably going to change mine out soon now. Have an 01 with the ssi so ya better to do it now. 

Just yo be clear I read it right the old alternator will work with the new system right? Also how do u know which wires to hook up did it come with instructions?? Any chance u can overlay from your pic as to which wire went where? I have the exact same rear box. Again awesome job and thanks!!

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18 hours ago, vanwill52 said:

You probably already know about the Li-BIM 225 offered by Precision Circuits, Inc.  If not, take a look.  It interrupts charging to the lithium batteries on a time-based schedule.

 

Li-BIM for Lithium batteries.jpg

Sorry, Jim.  I can't remember much about the DUVAC I had that was equipped with an external regulator.  But it sounds like the "Excite" terminal of the alternator is connected to an "always-on" source.  The "Excite" terminal needs to be energized by an ignition-switched circuit.  I am not sure that installing the ML-ARC would fix that.  Check the "Excite" terminal on the alternator to see if it is energized even when the engine is not running.

I saw this earlier, but must admit I didn’t dig deep enough into its functionality.

At their site, it made sense on how it works and now is a must for me.

Thanks very much for jogging my memory and helping to to take some time to research 

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6 hours ago, Romeo84 said:

Literally was researching this topic this week. Amazing write up and explanation. Probably going to change mine out soon now. Have an 01 with the ssi so ya better to do it now. 

Just yo be clear I read it right the old alternator will work with the new system right? Also how do u know which wires to hook up did it come with instructions?? Any chance u can overlay from your pic as to which wire went where? I have the exact same rear box. Again awesome job and thanks!!

Yes, the old alternator will work.  You still have to connect the voltage sensing wire from the alternator to the positive post of one of the battery banks.  I don't think it would matter which battery bank you connected to, since both with be receiving a charging voltage.  For that matter, since the voltage-sensing feature was only to counter the 0.7 VDC drop across the SSI, I suppose you could simply connect it to the alternator's output post.  I've never done that, so I can't say from experience that it would work...just don't see any reason why not.

As for which wires to hook where, the directions that come with the ML-ACR are simple and clear.  Sorry, I'm not good at annotating pictures.  Basically, you take the center cable from your SSI (the alternator output) and combine it with the cable (from the SSI) going to your chassis batteries on ONE of the large posts of ML-ACR, and connect the other cable from the SSI (from house batteries) to the OTHER large post of the ML-ACR.  It's easy and the instructions are clear.  You can probably view the instructions on the Blue Sea site.

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5 minutes ago, vanwill52 said:

Yes, the old alternator will work.  You still have to connect the voltage sensing wire from the alternator to the positive post of one of the battery banks.  I don't think it would matter which battery bank you connected to, since both with be receiving a charging voltage.  For that matter, since the voltage-sensing feature was only to counter the 0.7 VDC drop across the SSI, I suppose you could simply connect it to the alternator's output post.  I've never done that, so I can't say from experience that it would work...just don't see any reason why not.

As for which wires to hook where, the directions that come with the ML-ACR are simple and clear.  Sorry, I'm not good at annotating pictures.  Basically, you take the center cable from your SSI (the alternator output) and combine it with the cable (from the SSI) going to your chassis batteries on ONE of the large posts of ML-ACR, and connect the other cable from the SSI (from house batteries) to the OTHER large post of the ML-ACR.  It's easy and the instructions are clear.  You can probably view the instructions on the Blue Sea site.

I prefer attaching to the positive on the chassis battery myself. 

It's personal choise .

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I replace my Leece Neville with a newer leece neville self exciting solid state 210 Amp alternator, the alternator does require a voltage signals from the batteries that tells it what the charge rate should be, it has the ac Terminal for alt light and tach, to solve the issue of the 12 volt signal that was not present on the positive cable running from alternator to battery isolator, I used the original ignition circuit lead that excited the old style alternator, in my coach that piggy backed of the fuel boost pump, now if I just put That wire to the battery terminal it would work but would supply power to the entire ignition circuit constantly as long as the alternator was turning, so I just put a diode in line that stops any voltage from the alternator from energizing the circuit, simple 5 dollar fix that allows virtually any alternator to be used that will fit, been 4 months,1000s of kilometres and this fix requires a little solder a piece of shrink tube and a $5 diode. No rewiring no different isolators or electronics. The original system works great and has for 20 years, I didn’t see the need To mess with it.

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20 hours ago, vanwill52 said:

Yes, the old alternator will work.  You still have to connect the voltage sensing wire from the alternator to the positive post of one of the battery banks.  I don't think it would matter which battery bank you connected to, since both with be receiving a charging voltage.  For that matter, since the voltage-sensing feature was only to counter the 0.7 VDC drop across the SSI, I suppose you could simply connect it to the alternator's output post.  I've never done that, so I can't say from experience that it would work...just don't see any reason why not.

As for which wires to hook where, the directions that come with the ML-ACR are simple and clear.  Sorry, I'm not good at annotating pictures.  Basically, you take the center cable from your SSI (the alternator output) and combine it with the cable (from the SSI) going to your chassis batteries on ONE of the large posts of ML-ACR, and connect the other cable from the SSI (from house batteries) to the OTHER large post of the ML-ACR.  It's easy and the instructions are clear.  You can probably view the instructions on the Blue Sea site.

I would connect the sense wire to the alternator output, so the alternator would then sense whatever voltage that was coming from whatever batteries it was connected to at the moment.  The ML-ACR should have negligible voltage drop, which was the purpose of having the separate chassis battery sense with the SSI.

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So after watching the various posts on the Bluesea ML-ACR installs, and with talking to Van regarding the install I went ahead and bit the bullet and installed on in May of this year.  I was starting to question my BIRD and Isolation relay as it seemed like my batteries were not being charged correctly so decided to go ahead with the install itself, which was easy but I did need another wire from the rear electrical bay to the front dash, which was a challenge in itself.  The system works as designed, when there is a charging source on either side the ML-ACR closes and both battery banks charge. 

Since the install I have seen several posts on the IRV2 forum regarding the system and to be cautious if your house batteries are depleted as it will put a burden on the alternator which in the long term may  be a problem.  I have a Silverleaf VMSpc to monitor my engine, transmission and charge voltage.   So on my recent trip I noticed that I was getting some fluctuations in the alternator charge voltage, sometimes bouncing down to 13.6 volts.  I don't remember seeing this before, maybe I'm now paranoid.   I also have a voltage monitor for my house battery on the front dash.  So I would use the switch for the ML-ARC and disconnect the batteries.  After an hour or two I'd flip it back on.  This seemed to cure the voltage fluctations.

I've also read that it may not be a good idea to run the generator with the banks connected.  I seldom run the generator when driving if I am by myself but if my wife riding along with the dogs we usually crank it up when it starts getting warm.  But this problem again is solved by just flipping the switch.  There is an option to isolate the two systems if the generator is running by connecting one wire to the generator sense wire.  I may end up doing this since my wife won't be nearly as observant of what is going on. 

 

All in all I think installing the Bluesea ML-ARC it is a simple solution simplifying the charging system of your coach.

Edited by jacwjames
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New to MHs. Converted 300AH house battery bank on cruising sailboat to 700AH, added diesel generator, inverter/charger and 450 watts solar doing all the design and work myself. BlueSea is one of the most trusted brands on boats. Many cruisers replace the weak factory alternators with brands from Balmar. Their alternators accept an external regulator that adjusts the field current to get three stage charging based on battery voltage and temp. Monitors both battery and alternator temperatures and can reduce charging current as needed. The 160 amp LN on many Cummins looks a lot like an alternator they had a few years ago.  Sterling Power USA has pretty much any battery bank combining system you need. DC to DC battery chargers that allow you to charge LI-FE from a FLA or AGM starting bank. Battery Chemistry Modules that work very similar. 

A battery does not care if is on a boat or MH. Our sailboat was not connected to shore power for months at a time so marine can be a little more demanding on a battery bank.  Many boats regularly only get to 90% charged. Compass Marine has an excellent series of how-to articles on making your own cables, battery tests, monitoring systems etc. at https://marinehowto.com. I would recommend anyone looking at upgrading their system to spend a little time going thru their articles.

I have called a couple of alternator shops in Tulsa to see if they could rewire my alternator to have an external field coil connection. I would like to have a 3 step charging profile. They have no idea of what I am trying to do. I know where the Big Boy is on my coach. Still reading thru posts to try and get a good idea of how it is controlled. 

Knowledge is good. 

 

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I find this very interesting and I think I am motivated to pull out the old bird, etc. I am not even sure that my 1 solar panel even works so it would probably be a good time to pull that system out. Looking at your picture (excellent work) and the picture on AMZ I see a pigtail of assorted wires. Does it become clear once reading the install manual where the heck that bundle of wires goes? 

 

Thanks for the write up,

Ken

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1 hour ago, Grampy OG said:

I find this very interesting and I think I am motivated to pull out the old bird, etc. I am not even sure that my 1 solar panel even works so it would probably be a good time to pull that system out. Looking at your picture (excellent work) and the picture on AMZ I see a pigtail of assorted wires. Does it become clear once reading the install manual where the heck that bundle of wires goes? 

 

Thanks for the write up,

Ken

Ken, one need not connect even a single small wire for the ML-ACR to do its job.  The first small wire you MIGHT consider using is the one that allows you to remotely control (override) the built-in programming of the ML-ACR using a switch that pops right into the previous "Battery Boost" location.  The ML-ACR offers several options like disconnecting when the engine is cranking, disconnecting when alternator and genny are running, etc.  Most folks do not use those options, but they are available.  It is a VERY capable device that is simple, bulletproof, and guaranteed for as long as you own it.

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12 hours ago, vanwill52 said:

Ken, one need not connect even a single small wire for the ML-ACR to do its job.  The first small wire you MIGHT consider using is the one that allows you to remotely control (override) the built-in programming of the ML-ACR using a switch that pops right into the previous "Battery Boost" location.  The ML-ACR offers several options like disconnecting when the engine is cranking, disconnecting when alternator and genny are running, etc.  Most folks do not use those options, but they are available.  It is a VERY capable device that is simple, bulletproof, and guaranteed for as long as you own it.

Thank you Van. I am on the road until September and I think I will cross my fingers and do the job at home where I have access to all of my tools. I probably won't change my battery disconnects as they seem to work just fine. From what I can see each one of the systems currently installed (bird, isolator, BB) would cost as much as your unit should they fail and would be a hassle to locate modern versions. I am excited to try this. My only concern is I believe you mention the loss of the battery boost button but that is probably not the end of the world. 

Ken

 

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If you install the switch that comes with the Bluesea ML-ACR you will have the battery boost function.  The switch fits into the same hole as your current switch.  It will require one addtional wire from the dash to the electrical bay but the wiring is pretty easy (even I could figure it out).  Once installed it will let you select Auto, Off, or ON.  While parked, with the switch in auto and either running generator or shore power it will charge both battery banks.  If you are driving you can leave it in auto and the alternator would charge house batteries.  If not plugged in and need boost function just flip it to ON and it will combine both battery banks.  Or you can turn it off and it will isolate both battery banks. 

There are options to wire the switch where it could  automatically isolate batteries while starting and/or isolate if engine and generator are running. 

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4 minutes ago, jacwjames said:

If you install the switch that comes with the Bluesea ML-ACR you will have the battery boost function.  The switch fits into the same hole as your current switch.  It will require one addtional wire from the dash to the electrical bay but the wiring is pretty easy (even I could figure it out).  Once installed it will let you select Auto, Off, or ON.  While parked, with the switch in auto and either running generator or shore power it will charge both battery banks.  If you are driving you can leave it in auto and the alternator would charge house batteries.  If not plugged in and need boost function just flip it to ON and it will combine both battery banks.  Or you can turn it off and it will isolate both battery banks. 

There are options to wire the switch where it could  automatically isolate batteries while starting and/or isolate if engine and generator are running. 

Oh thanks for that quick update Jim. I was just pulling the trigger ordering the unit. I changed my mind. I am parked for another 6 weeks. It looks like a one or two hour job to put the new unit in place. I was a bit (and still a little bit) confused as to the on/off/auto portion but I am sure it will become clear as I move along. I am still not quite sure why you would change which bank of batteries is charging, in other words why not leave it on AUTO but I am sure I will figure it out. This is shaping up to be one of the better $200 upgrades I have done to my aging '03 parts. 

I am sure as I move along with this you and Van may see a couple more questions from me. 

Got to love the Monacoers. Bill is smiling down on us. 

Ken

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I usually leave mine in Auto

But from what I've read, if your house batteries are discharged after a night of boon docking it may work the alternator hard to charge the batteries back to fully charged.  Some people recommend running the generator for a while to charge them and/or isolating the batteries after ~1/2 or charging and then turn it back on after the alternator cools for a while. 

Some also isolate if you are running the generator to run AC's as it may cause the alternator light to come on.  That or you can wire the ML-ACR to isolate the batteries if the generator is running. 

I'm still on a learning curve. 

Also, with the switch you can turn the ML-ACR off, ON, or Auto right from your drivers seat.

 

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8 hours ago, jacwjames said:

I usually leave mine in Auto

But from what I've read, if your house batteries are discharged after a night of boon docking it may work the alternator hard to charge the batteries back to fully charged.  Some people recommend running the generator for a while to charge them and/or isolating the batteries after ~1/2 or charging and then turn it back on after the alternator cools for a while. 

Some also isolate if you are running the generator to run AC's as it may cause the alternator light to come on.  That or you can wire the ML-ACR to isolate the batteries if the generator is running. 

I'm still on a learning curve. 

Also, with the switch you can turn the ML-ACR off, ON, or Auto right from your drivers seat.

 

Awesome. Mine arrives tomorrow. I will report back to the group! 

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I’m back on the fence a bit. Now that I think about using the Gen for A/C while moving. 
 

The new inverter had a separate output to charge chassis batteries (lead) while plugged in or on genny. And charge house (lithium) at the same time. Might just use Dc/Dc charger to charge house batteries off Alternator. 
 

Wrapping my head around it all. I think I have just a regular alternator as I don’t have the large heat sink Van shows in his pic. My battery compartment is pretty simple 

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