Duvac or not

[DaveBunker]

Can someone tell me how to tell if my 2004 Camelot is a Duvac system? I have no clue. What is the definition.

[barmcd]

The Duvac system will have a sense wire from the battery isolator to the alternator. I believe that one wire is the only difference.

[CountryB]

As far as I know, the DUVAC system has the "three terminal" battery isolator box (similar to photo below) rather than the "Big Boy isolator in the newer model coaches.
Post a photo of your battery box area (solenoids, "devices", and such) and we can tell you what you have.

[barmcd]

Originally Posted by CountryB

As far as I know, the DUVAC system has the "three terminal" battery isolator box (similar to photo below) rather than the "Big Boy isolator in the newer model coaches.
Post a photo of your battery box area (solenoids, "devices", and such) and we can tell you what you have.

I have that battery isolator and a big boy relay in my 2000 Dynasty. What is a big boy isolator? Is that also called a BIRD which I think I don't have.

[CountryB]

The BIRD is the "Bi-Directional Isolator Relay Delay". It does what the DUVAC does, that is it separates (isolates) the House batteries from the Chassis batteries. This setup uses the BIRD control box and the Big Boy Battery Isolator. See picture of my Coach electric bay.

Big Boy also makes a couple of "Battery Disconnect" solenoids. A small one that is commonly used for the 12V interior power disconnect (a.k.a. Salesman Switch) which my coach has (but sort of out of view in the photo), and a large 200A battery disconnect solenoid (the bottom picture is the 200A Disconnect) which my coach does not have (I have manual battery disconnect switches).

This Big Boy Disconnect is similar in size and shape to the Isolator, shown in the top photo) but they function differently.

[rvhotrod]

Originally Posted by barmcd

I have that battery isolator and a big boy relay in my 2000 Dynasty. What is a big boy isolator? Is that also called a BIRD which I think I don't have.

Dennis I am curious, my 2000 Dynasty does not have a Big Boy, could you post a picture of yours.
Thanks in Advance
Dennis

[VanDiemen23]

This is much easier than you think. There are relay isolators such as the BIRD/Big Boy system, and there are diode isolators - you can tell them because they have a huge heat sink. If you have a diode isolator then you need the sense wire that goes to the batteries so that the alternator knows to bump up the voltage to compensate for the .75 volt drop across the diode. It has to go to the battery side, not the center post, otherwise it will be measuring it's own voltage BEORE the diode, rather than the battery voltage AFTER the diode.

[twinboat]

Many diode isolator systems also have a " Big Boy " solenoid just below or above them.

It is there as a boost solenoid ONLY and controlled by a dash switch. It is paralled across the chassis and house posts of the diode isolator.

Diodes isolators are simple one way electric check valves.
The alternator output is sent to the center post of two diodes and the output of the diodes goes to each battery. Because diodes block current from coming back, the alternator regulator has no way to sense battery voltage. That voltage is needed to regulate the output. There lies the need for the sense wire to the Duvac terminal.

Disconnect that sense wire or install a internally sensing alternator ( Delco )and you get serious overcharging.

Since diode isolators are only tied into the alternator output, they are not, and can not be Bi-Directional. The " B " in BIRD is bi-directional.

Many diode isolator equipped MH have another device to handle chassis battery charging while on shore power. Its actually another smaller diode type isolator tied into the house charging system.

In newer MHs that don't have diode isolators, the Duvac terminal is still used.
Sensing control voltage directly at the battery is always more accurate then sensing it at the alternators output terminal.

Diode isolators went out of fashion as house battery banks grew and alternator output increased. Charging batteries based only on the chassis battery condition left the house batteries undercharged.

Solenoid type isolators, used now days, connect the 2 battery banks together as one, as long as there is a charging source. An automatic jumper cable.

Some are one direction ( chassis to house ) and some are Bi-direction, ( charging from either source. ). They can be controlled by just turning on the key, an engine oil pressure switch, or voltage sensing devices like the BIRD.

Clear now ?

PS: Some suppliers offer Delco alternators with Dulvac type control. Your not stuck with the L/N alternator.

[twinboat]

Here is a picture of a MH with both a isolator and boost solenoid.

You can see that the big solenoid connects the house and chassis batteries together for boost starting, while the isolator splits the alternator output to both banks.

The original " house to chassis " charging device failed and this owner replaced it with the Trik L Start. Serves the same purpose.

[barmcd]

Originally Posted by rvhotrod

Dennis I am curious, my 2000 Dynasty does not have a Big Boy, could you post a picture of yours.
Thanks in Advance
Dennis

Yeah, I'll try to remember to take a picture tonight when I get home.

[barmcd]

Originally Posted by twinboat

Many diode isolator systems also have a " Big Boy " solenoid just below or above them.

It is there as a boost solenoid ONLY and controlled by a dash switch. It is paralled across the chassis and house posts of the diode isolator.

Diodes isolators are simple one way electric check valves.
The alternator output is sent to the center post of two diodes and the output of the diodes goes to each battery. Because diodes block current from coming back, the alternator regulator has no way to sense battery voltage. That voltage is needed to regulate the output. There lies the need for the sense wire to the Duvac terminal.

Disconnect that sense wire or install a internally sensing alternator ( Delco )and you get serious overcharging.

Since diode isolators are only tied into the alternator output, they are not, and can not be Bi-Directional. The " B " in BIRD is bi-directional.

Many diode isolator equipped MH have another device to handle chassis battery charging while on shore power. Its actually another smaller diode type isolator tied into the house charging system.

In newer MHs that don't have diode isolators, the Duvac terminal is still used.
Sensing control voltage directly at the battery is always more accurate then sensing it at the alternators output terminal.

Diode isolators went out of fashion as house battery banks grew and alternator output increased. Charging batteries based only on the chassis battery condition left the house batteries undercharged.

Solenoid type isolators, used now days, connect the 2 battery banks together as one, as long as there is a charging source. An automatic jumper cable.

Some are one direction ( chassis to house ) and some are Bi-direction, ( charging from either source. ). They can be controlled by just turning on the key, an engine oil pressure switch, or voltage sensing devices like the BIRD.

Clear now ?

PS: Some suppliers offer Delco alternators with Dulvac type control. Your not stuck with the L/N alternator.

I think that's what I have on my 2000 Dynasty as the only wire going to the control input of the solenoid is the orange wire coming from the boost switch on the driver's side panel.

[barmcd]

Originally Posted by twinboat

Many diode isolator systems also have a " Big Boy " solenoid just below or above them.

It is there as a boost solenoid ONLY and controlled by a dash switch. It is paralled across the chassis and house posts of the diode isolator.

Diodes isolators are simple one way electric check valves.
The alternator output is sent to the center post of two diodes and the output of the diodes goes to each battery. Because diodes block current from coming back, the alternator regulator has no way to sense battery voltage. That voltage is needed to regulate the output. There lies the need for the sense wire to the Duvac terminal.

Disconnect that sense wire or install a internally sensing alternator ( Delco )and you get serious overcharging.

Since diode isolators are only tied into the alternator output, they are not, and can not be Bi-Directional. The " B " in BIRD is bi-directional.

Many diode isolator equipped MH have another device to handle chassis battery charging while on shore power. Its actually another smaller diode type isolator tied into the house charging system.

In newer MHs that don't have diode isolators, the Duvac terminal is still used.
Sensing control voltage directly at the battery is always more accurate then sensing it at the alternators output terminal.

Diode isolators went out of fashion as house battery banks grew and alternator output increased. Charging batteries based only on the chassis battery condition left the house batteries undercharged.

Solenoid type isolators, used now days, connect the 2 battery banks together as one, as long as there is a charging source. An automatic jumper cable.

Some are one direction ( chassis to house ) and some are Bi-direction, ( charging from either source. ). They can be controlled by just turning on the key, an engine oil pressure switch, or voltage sensing devices like the BIRD.

Clear now ?

PS: Some suppliers offer Delco alternators with Dulvac type control. Your not stuck with the L/N alternator.

Is this the Lambert 415 Battery Maintainer?

[twinboat]

Originally Posted by barmcd

Is this the Lambert 415 Battery Maintainer?

Yes, that's the name of it.

[CJScepter]

If you go to AJ-elec.com they have pic's of motorhome alternators, front and rear on most. My 2003 HR with 8.3 Cummins used the 2824LC.