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jim427 · 04-20-2019, 05:35 PM

Just realized I posted this in the wrong place the first time,......newbie!!

Recently I noticed a "buzzing" in the back of the coach when it is parked, on shore power, and both battery relays are in the on position. I finally found it in the battery compartment, and it was the 200 amp. SPST relay mounted on the wall of the compartment. I tapped on it and the noise temporarily went away, but later returned. Then I started the engine, and the 12vdc house lights came on along with the running engine, but then both died. After 3 cycles of this the engine and lights remained on, but that relay is now oscillating on and off when both the battery relay switches inside are turned on. Not knowing what's going on I am leaving both relay switches off until hopefully someone here has an idea what's happening. Is the relay now bad? I see it has a bolt head on top and thought maybe I could open it up and clean the contacts?? Any ideas are appreciated.

jim427 · 04-21-2019, 11:10 AM

Update. I took the relay apart and cleaned the contacts. Nothing really looked out of the ordinary, but I put everything back together and for the moment it's holding. But I did notice that the trigger voltage for the relay coming from the battery control board is 5 vdc and that's a 12 vdc relay. Does anyone know if this is normal?v

MSHappyCampers · 04-21-2019, 11:52 AM

Hi ! Welcome to IRV2! We're sure glad you joined the gang!

I've never had that problem but it sounds like a bad relay to me! Have fun and keep her between the ditches!

Good luck, happy trails, and God bless!

twinboat · 04-21-2019, 12:10 PM

Some isolation relays controls use a shot of 12 volts to close the contacts and then drop to a lower holding voltage so they stay cool.

You could try to measure the control voltage, at the point in time it first closes the relay, to see if yours is working that way.

jim427 · 04-25-2019, 08:41 AM

Thanks to everyone who replied trying to help. Turns out it was a simple fix. I had tunnel vision focused on that relay and control board. I just didn't notice that somehow my converter had been switched off, therefore the batteries weren't being charged. No telling how long that had been going on. They had been hot enough to start the coach and move several times, and charge off the alternator, but it finally sat long enough for that relay to start acting up. I put all batteries on a charger, and turned my converter back on. Amazing how everything works now. And apparently that board does drop the relay voltage to 6 vdc once it energizes. Thanks again.

Sbrownstein · 04-25-2019, 08:45 AM

Quote:

Originally Posted by jim427

Update. I took the relay apart and cleaned the contacts. Nothing really looked out of the ordinary, but I put everything back together and for the moment it's holding. But I did notice that the trigger voltage for the relay coming from the battery control board is 5 vdc and that's a 12 vdc relay. Does anyone know if this is normal?v

Jim. That is normal for bigger relays on diesels. They hit them with 12 to close and then hold with 5 or 6. In addition, the relay is mounted outside te BCC due to heat dissipation.