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Topic: Is my DUVAC isolator fried? (Read 574 times) previous topic - next topic

Is my DUVAC isolator fried?

'93 U300 owner here. Please forgive my lack of knowledge here I am doing my best to learn as much as possible.

I took my Grand Villa into Branson Motor Coach to have a basic safety inspection done and they burned out my starter motor in the shop then blamed it on the boost connection "Overamping" the starter. So you can see here  in the first picture there is a cut wire with fresh electrical tape on the end, I assume that's the boost.

While working on my isolator alongside the house batteries the shop mechanic moved wires and didn't secure them. One of my wires on the post to the right is melted and the loose wire from the other post is also partially melted. So when I was driving I imagine these two wires met and sparks began to fly. Is my diagnosis correct?

Can this isolator be saved? The cracks look severe, I was driving and lost all power from the alternator so I only had what charge was on the chassis batteries. I tried starting the generator and flipped the boost switch, got nothing. If you can give me any advice I'm ready to listen.

Re: Is my DUVAC isolator fried?

Reply #1 –
Welcome to the ForeForum.

Good grief.  That has been severely overheated.

Yes, likely, it has failed, along with the wires to it.

Short term, there are some easy work-arounds, assuming the wires are still marginally OK.

Are you needing to move the coach with the current issue are you interested in fixing it first?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Is my DUVAC isolator fried?

Reply #2 –
Quote from: wolfe10 –
Welcome to the ForeForum.

Good grief.  That has been severely overheated.

Yes, likely, it has failed, along with the wires to it.

Short term, there are some easy work-arounds, assuming the wires are still marginally OK.

Are you needing to move the coach with the current issue are you interested in fixing it first?
Hi Brett, thank you for confirming my fears.

I would certainly like to fix it first if it can be done in a timely manner. We are currently visiting family in Colorado and feel very welcome here, however we are also traveling to Southeast Alaska and we've got a boat to catch in Bellingham Washington on June 7th, so the clock is ticking.

What would you recommend?

Re: Is my DUVAC isolator fried?

Reply #3 –
Long term: trouble shoot the charging system (alternator, isolator, batteries) and replace what is bad/overheated.

Short term:  work-arounds that will get you to Alaska.

Let us know what you want.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Is my DUVAC isolator fried?

Reply #4 –
Quote from: wolfe10 –
Long term: trouble shoot the charging system (alternator, isolator, batteries) and replace what is bad/overheated.

Short term:  work-arounds that will get you to Alaska.

Let us know what you want.
Understood Brett! The batteries are all taking charge and holding it well. House batteries via shore power and chassis via a tender. Terminal connections are good.

While we are here stranded I am putting in a new alternator (Prestolite Leece-Neville idlepro 210A).

That just leaves one deep fried isolator. If you have recommendations for replacement I can look at shipping times and perhaps have something in hand before getting back on the road.

I don't like it this way, but I think short-term workaround is for the best. How should I proceed?

Re: Is my DUVAC isolator fried?

Reply #5 –
Short term, combine wire to center of battery isolator (from alternator B+) with the wires from the outer lugs (one to chassis battery and the other to the house battery).

Both battery banks will be charged by both alternator and shore power.

BUT, the two banks will also DISCHARGE since the are combined. So, to prevent both banks being discharged, separate the wire (and insulate it from touching ground) to the chassis battery when dry camping.

Again, this assumes that the wires showing burning are still OK (or replace them/at least back to good clean copper).
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Is my DUVAC isolator fried?

Reply #6 –
Are you sure that you ordered the Prestolite Leece-Neville idlepro  wired up in the DUVAC configuration? If not you will be chaseing you tail around as you progress with the rewiring project.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Is my DUVAC isolator fried?

Reply #7 –
Quote from: Pamela & Mike –
Are you sure that you ordered the Prestolite Leece-Neville idlepro  wired up in the DUVAC configuration? If not you will be chaseing you tail around as you progress with the rewiring project.

Mike
Hi Mike, this is the one I ordered. It appears to have the post for the remote sensing wire, would you agree?

https://prestolitesuperstore.com/Category/A160208/Genuine-Prestolite-Leece-Neville-New-AVI160J2008-New-Alternator-AVI-Series-J180-Mount-type-12V-210A/

Re: Is my DUVAC isolator fried?

Reply #8 –
Quote from: Matthew and Serenity –
Hi Mike, this is the one I ordered. It appears to have the post for the remote sensing wire, would you agree?
Matthew,

Not Mike, but that alternator looks fine.  I found another listing that verifies it does have the "remote sense" terminal, and also that it is "self exciting" which means it does not require a separate EXCITE wire. 

Leece Neville AVI160J2008 Alternator | FinditParts

As far as a replacement isolator, if it was me I would recommend the Victron ArgoFET 200-2AC model.  This model is superior to the old diode based isolator that came on your coach.  It has almost zero voltage loss between the alternator input post and the two battery posts.  In addition, it has a extra "Energize" terminal that will be very handy should you ever decide to upgrade your charging system.  Amazon can probably get one to you in 2 days, and the price is right.  But that is just my opinion...

Amazon.com: Victron Energy Argofet Battery Isolators 200-2AC (2 Batteries...

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Is my DUVAC isolator fried?

Reply #9 –
In looking at the pictures it looks like a plasma arc fried everything.  I would remove the isolator.  For short term, go back to clean wire and you can get some screw type lugs to fit  on the wire ends. Then take a bolt and nut to connect the lugs together.  Take electrical tape and tape up to protect the connections from touching anything.  May need a tie rap or two to have secure.

Then when you get back you can either spice the cables or get new cables along with a new isolator.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Is my DUVAC isolator fried?

Reply #10 –
Well after a neighborhood honeybee swarm capture, I just now had time to get back and see that Chuck has jumped in and helped out. This is one thing about this Forum as there are several here that can answer questions about the requirements of these coaches.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Is my DUVAC isolator fried?

Reply #11 –

Matthew,

I understand you have scheduling constraints, but looking at your photos I see another item which, IMO, should be replaced.

You have two electric solenoids mounted on the isolator panel, just below the isolator.  One of them is newer and cleaner - the other looks old and crusty.  If your panel follows the conventional layout, the newer one (on the left) is the AUX START solenoid, and the crusty one (on the right) is the BOOST solenoid.  A better photo of the entire panel would help confirm this layout.  Both of these devices are essential to proper operation of your coach.

Whenever you get around to ordering new parts for your damaged isolator panel, I would recommend you include two new solenoids.  The most often recommended model for this application is the Cole Hersee 24213.  This is an excellent quality continuous duty rated 200A solenoid.  Install these solenoids once and never worry about them again.

Amazon.com: Cole Hersee 24213 12V 200A Continuous Solenoid : Automotive

If you received factory owner manuals with your coach, you should find a B-2126 electric diagram in one of the books.  If you didn't get the manuals, the images below show a typical isolator panel with a 3-post isolator and both solenoids.  Your panel may differ slightly in the arrangement of components, but these should be close enough to use as wiring examples when you rebuild your damaged panel.

https://www.foreforums.com/index.php?media/item/b-2126-automotive-wiring-diagram.4746/

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"
 

Re: Is my DUVAC isolator fried?

Reply #12 –
Another "battery isolator" idea that is KISS:

Marine ON-OFF manual switch (not 1-both-2-off switch).

Alternator B+ and chassis battery to one lug.
House battery to other lug.

Switch off, chassis battery gets charged by alternator.

Switch on, both banks get charged by alternator OR shore power (think of it as a KISS "battery combine".

On most coaches can be mounted at the foot of the bed for easy use.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020