Big Boy Relay

[paul65k]

So the big boy combiner seems to be not functioning correctly and I wanted to see if anyone has any experience with these.

So on our 2001 36FDDS (pre-vansco) the combiner was working fine until I had an alternator failure in March. I used it a whole bunch on a trip to keep the chassis batteries charged from the house bank which was large and charged by solar. I probably had it engaged for quite some time and may have burned it out????

So at this point it seems to be engaging as I can hear the distinct mechanical engagement when the boost switch is activated but there is not power coming through to the other terminal and there is also no continuity when engaged between the 2 terminals.

Is this a failure of the u it itself? I was thinking it might be a fuse but wouldn’t it just not respond to the switch if it was a fuse??

Any experience with this relay here???

Thanks in advance everyone

[Old Scout]

….pretty simple device....also pretty heavy-duty--like 300 amps and designed for continuous duty.....you heard it "click" so sounds like dash switch is working--believe it is a ground-out switch vs a positive/power switch..... some say you can open them up and clean the contacts---probably time for a new one--perhaps be able to find a more modern option??????

[paul65k]

Originally Posted by Old Scout

….pretty simple device....also pretty heavy-duty--like 300 amps and designed for continuous duty.....you heard it "click" so sounds like dash switch is working--believe it is a ground-out switch vs a positive/power switch..... some say you can open them up and clean the contacts---probably time for a new one--perhaps be able to find a more modern option??????

Yeah you're probably right Dean!....I was just trying to make sure it wasn't something simple

I realize there are more modern options but I found one on eBay for $150 so I'll just replace it.....I mean, after all, it is 19 years old

In the mean time I re-routed the cable from the BB to the Chassis battery buss bar to keep the chassis batteries topped off in preparation for our trip next week!!

[rrthor]

Paul just some food for thought. My coach is a Vansco coach but it has the same kind of solenoid. Mine is made by Trombetta and yours is made by Intellitec. I believe they are both 200 amp continuous duty solenoids.

I just replaced mine. It is almost five years old. It was still working kinda. In the battery bay I have volt meters for the chassis and house batteries banks so I can see the voltage on both banks. When Vansco would energize the solenoid I could hear the solenoid energize and the solenoid would get warm to the touch but I would not immediately see the voltage increase on the chassis batteries. It might take 20-30 minutes before the solenoid would pass power from one bank to the other. I thought that was odd but it always eventually worked.

I bought a new one on Amazon for $58, installed it and all is well. When Vansco triggers the solenoid power flows between the banks immediately. I disassembled the old solenoid and the contacts were in pretty bad shape (picture below). At $58 you might try this solenoid.

[mchero]

My trombetta needs to be replaced as well.

[Steve and Linda's APEX]

Would a Sure Power battery separator work?

[Brianna]

I got a replacement big boy but have not installed yet because I can't reach the nuts on the inside of the chassis rail and the bolt heads on the outside at the same time. A two person job? Don't suppose the nuts are tack welded.....

[mchero]

Those nuts will be arc welded if you try and swap it out live!

LOL

Take lots of pics then disconnect both battery banks. I need to get off my rear and replace my isolator relay as well.

I have herd of someone holding a hot battery cable in hand contacting ring. Bump the ring against ground and instant glowing red hot ring!

[paul65k]

Originally Posted by Brianna

I got a replacement big boy but have not installed yet because I can't reach the nuts on the inside of the chassis rail and the bolt heads on the outside at the same time. A two-person job? Don't suppose the nuts are tack welded.....

Same here.......I was thinking I might reach up in there and put some JBWeld about the edges of the nuts (after cleaning of course) and then it will be a piece of cake to replace and will make removal and future cleaning easier as well.....I wonder if that will work??

[twinboat]

Vice grips locked TIGHT to the bolt head.

If they look real rusty, tighten them until they snap. Watch your knuckles.

[Unplanned Tourist]

Yep, vice grips are your second set of hands.

[rrthor]

The previous owner of my coach installed the solenoid using wood screws. When I replaced the solenoid I fabricate a 1/4" thick aluminum plate and tapped two 1/4-20 holes in the plate the same center distance as the original holes WRV made. Since the plastic panel that has all those components mounted to it is offset from the frame rails I was able to push that plate up behind the panel and the fit is tight enough to hold the plate in place when I remove the screws holding the solenoid in place. Solenoid replacement is now pretty easy.

[paul65k]

Originally Posted by Unplanned

Yep, vice grips are your second set of hands.

Yeah, that works but not as easy the way the Alpine frame is laid out

[Brianna]

Hmmm.
Vice grips....that might work for disassembly, but I still need that 2nd set of hands for installation.