Battery Isolator getting ready to fail?

[MandG-Fun]

I am getting ready for a house battery replacement on my 2000 Dynasty and opened the RRB door today to find that the Cole Hersey battery isolator has a small crack running vertically between the posts. I'm guessing that the unit got very hot because it appears that the black insulator material liquified and leaked along the crack. There is just a small amount that leaked out but certainly raising a red flag.

I currently have the 3 - 12V lead acid batteries that came with the coach when I bought it (they are in marginal condition) and I am replacing them with 4 - 6V 220A AGM's.

I'm interested to hear opinions about the current condition of my battery
isolator. And recommendations if it should that be replaced right away and if so, with the same model or something different.

Thanks,
Glenn

[Happycarz]

Is your isolator, along with other relays, solenoids, etc, in a white box with a clear plastic cover on it?

[lonestarace]

We did a mod and write-up w/pics
http://www.irv2.com/forums/f115/mod-...ns-135217.html

[MSHappyCampers]

I had to replace the Battery Isolator Relay in my 2002 Windsor a while back. The contacts were stuck closed and keeping the two sets of batteries tied together.

I replaced it with a Bear heavy-duty contactor from MurCal, Inc. Their part number was TMT 114-1211-020. I paid $48.95 plus $4.99 shipping. Their phone number is 661-272-4700.

You can remove the cables from either of the large terminals and use a multi-meter to check resistance between the two large posts. You should not have any continuity reading between them. Be sure to turn off BOTH battery disconnect switches before you do this!

Good luck, happy trails, and God bless!

[lonestarace]

Originally Posted by MSHappyCampers

I had to replace the Battery Isolator Relay in my 2002 Windsor a while back. The contacts were stuck closed and keeping the two sets of batteries tied together.

The OP has a different type isolator from yours. His isolator is a heat sink type(no points) like the big blue thing in the pic below, not a big boy point type which I believe you have. The pic below is of our 00 Signature after I did the cooling fans/snap switch mod.

[InfinityJim]

Sure sounds like it's in need of replacement if the unit is cracked and leaking... But it could still work? Either way I'd replace it. These isolator relays need to be sized correctly. I always look at the alternator to see what it's max output amp rating is and go at least 30% bigger rated relay - or close to that. It has to be at least the same, but bigger is always better.

The relay I use mostly is the blue sea L series L Solenoid - 12/24V DC 250A - Blue Sea Systems

Jim

[MandG-Fun]

I'm just going to keep it simple so I ordered the same Cole Hersee isolator. I like the idea of adding cooling like Lonestarace, just not sure I can easily get to the back side of my RRB enclosure to add the fans. I'll need to study that one a bit before getting out the hole saw.

Not sure how common this is but the damage to the isolator seems pretty strange to me. It must have really overheated. Once I remove it I'll try dissecting it to see what I see. In the picture below the top and bottom yellow arrows show how much the black insulator material slid down from the heatsink. The center arrow is pointing to the stream of melted insulator that leaked out of the crack.

[Happycarz]

My 99 Dynasty isolator died after 10 months. I added the silver duct seen in the photo and sold the coach 9 years later without another issue.

I put one end in the fresh air duct that comes down from the roof and the other on top of the upper vent on the box.

[lonestarace]

It is set up for failure because Monaco's engineers(yeah right), in their infinite wisdom, mounted it in/on an enclosed plastic box that does not absorb heat and lacks airflow. We, the owners/users, like to depleat our large bank of house batteries(boondocking). Then we start the engine and its powerful alternator pumps energy thru the isolator like nobodies business, and it overheats because it was doomed to begin with. Adding fan(s)/ventilation can help a bad situation.

Operationally, starting the less powerful generator and letting it recharge the house batteries for a while before starting the main engine will help too.

[jldacus]

someone replaced my isolator with a 160amp and it cracked, the isolator must match the alternator , mine is a 200 amp alternator and we put a 200 amp isolator on and no more trouble.