1999 Fleetwood Discovery 38 ft. battery relays

[jim427]

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.

[mchero]

tippytoe wrote:
That may be normal. The Fleetwood "Discovery" model is a diesel. I read once that the BCC on diesels give that relay a 'shot' of 12 volts to pick up the relay, then 6 volts to keep it picked up. Here's a link that has a link to the BCC pdf. (post #5 of this: http://www.irv2.com/forums/f107/bcc-and-adding-another-solenoid-question-323934.html .

BINGO

[enblethen]

Thanks for the update!
S**t happens!

[jim427]

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.

[tippytoe]

Here's a quote:
Thus, with later revision boards and with ignition off, the auxiliary start/charging
relay will drop out sooner (12.6VDC) to retain a greater amount of charge in the
chassis battery. It is normal for the charging relay to remain pulled in after the
engine is turned off. Coil current is approximately 1/2A for both models. The
diesel model has a heavier, intermittent duty coil. To enable the coil to be
continuously energized, full voltage is applied for 1/2 second and then the coil is
pulsed at approximately 50% duty cycle. Thus, a voltmeter will read about 6VDC
when the diesel relay is operating normally in closed position.
Gasoline and diesel models of Rev B and alter sense voltage from both the
ignition terminal and coach battery disconnect terminal. This allows the chassis
battery to be charged from the converter when on shore power. Necessary
conditions are : coach battery disconnect engaged, shore power on, converter
operating, and coach battery charged above 13.2VDC. When these conditions
are met the auxiliary charging relay will pull in and both batteries will be charged
in parallel.

[tippytoe]

That may be normal. The Fleetwood "Discovery" model is a diesel. I read once that the BCC on diesels give that relay a 'shot' of 12 volts to pick up the relay, then 6 volts to keep it picked up. Here's a link that has a link to the BCC pdf. (post #5 of this: http://www.irv2.com/forums/f107/bcc-and-adding-another-solenoid-question-323934.html .

[RLS7201]

Look at the circuit board in your BCC. There should be a connector for your isolator relay in the lower right hand corner. Make sure that connector has a good connection. Also, next to the connector is the fuse for that circuit. Make sure it is making a good connection.

Richard

[enblethen]

That is not normal for a 12 volt circuit. You need to locate the location of the voltage drop.
An electrical held relay will not fully engage with your low voltage.
Look at your Battery Control center for make and model.

[jim427]

This is not a latching relay.

[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?

[wolfe10]

enblethen wrote:
Some use a continuous 12 volt control signal while others use a momentary signal to energize/de-energize relay. Identification of the relay is important.

Good point. Could be a latching relay.

DO verify exactly what you have.

[enblethen]

Some use a continuous 12 volt control signal while others use a momentary signal to energize/de-energize relay. Identification of the relay is important.

[wolfe10]

Check voltage to the small signal terminal (s). If 12+ VDC, the relay is bad. If one small signal terminal it will be the positive (with ground through the relay's body). If two, one will be the positive, one the ground/negative.

You can also use a small jumper wire from the 12+VDC lug to the POSITIVE signal terminal after removing the wire to the positive signal terminal so you don't back-feed that circuit.

[enblethen]

Sounds like it could be low voltage on the control circuit. This could be from poor connections at the batteries. Voltage could be low through out the electrical system.
Reason the lights cme on was the alternator was powering the lights through the charge relay system then voltage dropped turning system off.
Start by cleaning battery cables.