2013 Diplomat voltage fluctuations

[KeithP]

Hi Everyone, I am new to the forum, I have a 2013 Diplomat 43 DFT, I just got back from a trip to Texas, to pick this new coach up, about a 1000 miles into the trip I noticed 

the voltage fluctuating between 12.2 and 12.6, so i fired up the generator and had 13.1 to 13.6, has anyone ever experienced anything like this.  

[jacwjames]

Where are you seeing the 12.2-12.6 readings.  Where are you seeing the 13.1 -13.6 readings.

My alternator puts out ~14.2 volts while driving down the road, this is based on my Silverleaf display. 

A couple years ago I removed the original components for charging both the house and chassis batteries.  I had a BIRD, Lambert 415 maintainer, and Isolation Solenoid. 

I replaced them with the Bluesea MLACR latching relay.  Now when driving my alternator will charge both sets of batteries with the 14.2 volts, and will charge to ~13.6 when plugged into shore power or running the genertor.

At rest after driving or unplugged my batteries will show 12.6 to start with and then deplete slowly.  I installed a Victron BVM 712 battery monitor so it shows me the voltage and consumption on the house batteries and shows me voltage on the chassis batteries. 

So you need to look at the wiring diagrams and determine what your charging system you have. 

[KeithP]

I tested at the batteries 

Vehicle electronics is not my strong suit, would I find my charging system in my manuals, or do I need to call Monaco.

Thanks 

[jacwjames]

Look in the manual, it will have a description of the electrical charging system

There may be a manual in the Downloads section and electrical schematics. 

[KeithP]

6 minutes ago, jacwjames said:

Look in the manual, it will have a description of the electrical charging system

There may be a manual in the Downloads section and electrical schematics. 

Thank you for your help!

[Frank McElroy]

1 hour ago, KeithP said:

Hi Everyone, I am new to the forum, I have a 2013 Diplomat 43 DFT, I just got back from a trip to Texas, to pick this new coach up, about a 1000 miles into the trip I noticed 

the voltage fluctuating between 12.2 and 12.6, so i fired up the generator and had 13.1 to 13.6, has anyone ever experienced anything like this.  

Not sure how the 2013 Diplomat electrical system is setup but if the voltage is fluctuating between 13.6 and 13.1, and the engine is cold, this is likely due to the engine intake grid heaters cycling on and off.  I've noticed this on startup for a few minutes on my ISL engine.

[Tom Cherry]

2 hours ago, KeithP said:

Hi Everyone, I am new to the forum, I have a 2013 Diplomat 43 DFT, I just got back from a trip to Texas, to pick this new coach up, about a 1000 miles into the trip I noticed 

the voltage fluctuating between 12.2 and 12.6, so i fired up the generator and had 13.1 to 13.6, has anyone ever experienced anything like this.  

First.  Where were you seeing the voltage display?  On the dash while the engine was running?  On the Magnum remote?

HOWEVER….after downloading your manual….you have a BIRD or BiDirectional charging system.  Read section 9 of the manual.  When you are driving, the alternator will recharge both the house bank as well as the Chassis bank.  This is a TRUE BIRD system that is controlled by an isolator module the we call a Intellitec Diesel 2.  There is a picture of it in the manual.  It checks the voltage on each bank.  Whichever bank has charging current…as in the House has the Generator or Shore and the Chassis has power, then there is a solenoid called the Big Boy and that solenoid closes and both banks will be charged. There is a diagram on this at the end of section 8 of the manual.

I SUSPECT that (or hope) that you are reading the Magnum remote.  The Magnum remote will display the voltage of the House batteries.  If you are NOT plugged into shore, then the voltage may fluctuate depending on the House load.  The interior lights are house 12 VDC. The water pump is house 12 VDC. The ceiling fans are 12 VDC.  If you have anything plugged into the interior outlets and on, like a phone charger, or fan or TV or entertainment center, then the inverter will be taking 12 VDC and turning it into 120 VAC.  When you start the generator, the generator provides 120 VAC and then powers all the interior 120 VAC outlets and charges the House battery and if the Chassis battery needs charging, it will also charge it.

Please take a picture of where you are reading the voltage.  Probably on the Magnum remote.  You should sit down and read your manual.  ALL sections…but specifically sections 8 & 9 as they cover the HOUSE and CHASSIS, respectively.

Motor Homes are “strange critters” to folks that don’t have any background in RV’s or especially Motor Homes.  Read and understand and learn.

Then, post a picture if it isn’t clear…

[KeithP]

On the dash, the voltage dropped slowly, below 12 the low battery light came on. So I started the generator and it got up to 14.1, but the display was still fluctuating 

Keithp

[Tom Cherry]

17 minutes ago, KeithP said:

On the dash, the voltage dropped slowly, below 12 the low battery light came on. So I started the generator and it got up to 14.1, but the display was still fluctuating 

Keithp

You have a failed or failing alternator.  With your Intellitec BIRD system, when you drive the usual mode or action is for the Alternator to charge the Chassis and if the house is low, then also the house.  However, in your case, the chassis bank was low due to NOT being recharged by the Alternator.  Thus, when you started the generator, BOTH systems were being charged and you saw the Chassis system….the dash voltmeter is connected to Chassis battery…so the chassis voltage jumped up to the normal charging voltage of the House.  The Magnum Inverter/Charger was recharging BOTH banks.

I wondered about that when I wrote my response….that is why I specifically asked.  The GOOD NEWS…your BIRD system is working properly.  

Therefore, you need to have a OTR or a Bus or Alternator shop check the system. Monaco used a special brand of Alternator. Leece Neville.  Many shops will try to sell you a different brand.  The Leece Neville has a peculiar type of charging system called a DUVAC.  Not many replacements have it and folks have had a world or trouble over the years when a shop with no knowledge tries to MAKE the wrong type of alternator work.

The common recommendation….find a high quality shop.  Tell them to rebuild the Leece Neville.  Tell them to replace all the components and ONLY to order the part from A distributor that sells Leece Neville parts.  Do NOT substitute or use off brands.  That will include the Voltage Regulator.  Tell them NOT to test the Diodes, just replace them with genuine Leece Neville parts.  If they can take it (a component) off, replace with a new Leece Neville.

Otherwise, tell them to cross reference your model and get the CURRENT Leece Neville new alternator.

TRUST ME…if you go aftermarket and the shop has no idea and just keeps switching wires to make it work….it will NOT…

[Benjamin]

Your alternator is not charging at those voltages.  It could be failed, or it could be a wiring issue outside of the alternator.  You'd have to test the voltages at the alternator to find out. I thought a BIRD replaced a DUVAC, so you'd have a DUVAC on older models, or a BIRD on newer models, but not both.  IF it's a duvac system, then there are Delco Remy alternators with remote sense that will work with the duvac system.  Or it could have been changed sometime over the years.  The remote sense is common in alternators, the DUVAC is simply wiring that remote sense to the starter battery to compensate for the voltage drop through the two diodes that connect the alternator to the chassis and house battery banks. 

[Tom Cherry]

1 hour ago, Benjamin said:

Your alternator is not charging at those voltages.  It could be failed, or it could be a wiring issue outside of the alternator.  You'd have to test the voltages at the alternator to find out. I thought a BIRD replaced a DUVAC, so you'd have a DUVAC on older models, or a BIRD on newer models, but not both.  IF it's a duvac system, then there are Delco Remy alternators with remote sense that will work with the duvac system.  Or it could have been changed sometime over the years.  The remote sense is common in alternators, the DUVAC is simply wiring that remote sense to the starter battery to compensate for the voltage drop through the two diodes that connect the alternator to the chassis and house battery banks. 

A BIRD SYSTEM has nothing to do with the alternator’s charging system. The BIRD is just a system to tie or jumper the house to the chassis when one needs tombe charged.  A BIRD system depends on each system to be capable of charging it’s own battery..  

For example the charger/inverter has to have 120 Vac to charge the house battery.

The chassis system is charged by the Alternator when the engine is running.

The BIRD SYSTEM determines if one bank is low and needs supplemental charging. Then the Big Boy solenoid engages and both systems are charged.  It also determines when to shutbdown if the other is fully charged. It also determines if one bank has a defective and can’t be charged.

Yes, the DUVAC is the type of sensing circuit that controls the Voltage regulator, which is inside the Alternator.  We have had hundreds of members that were told that a new alternator would work just fine, but the did not understand how Monaco used the sensing circuit in the chassis system.  Thus the advice to rebuild a well known brand of alternator rather than to install the wrong type.

However, we also have had folks that understand how the DUVAC works and how to install a different type.  You can search using the search box and put in Duvac.  Then click on Everywhere….and choose TOPICS.  Then read up.  Do the search again and this time choose FILES.  Lots of information…

 

 

[Benjamin]

A BIRD connects and disconnects the battery banks, so replaces the DUVAC system in the alternator charging circuit.  A BIRD should not affect the alternator, and you described how it produces the voltages that the OP saw with the alternator not charging, and the generator charging both banks when on. 

Motor homes are more complicated electrically than cars and pickups, but not quite as bad as fire trucks, and way less than military trucks, still easy to mess up. Some Delco Remy models come with optional remote sense and "relay" terminals.  Most universal replacement part numbers that would be commonly stocked should have both, but you never know.  The 22si, 24si, 28si are all available with the same remote sense and relay terminal that Leece Neville uses for the duvac system.