Battery disconnect or isolation solenoid? HELP!

[Moffittclan]

I think I might have a bad isolation solenoid because my house batteries aren't charging with the engine running...I tested by measuring volts on house batteries with engine off (12.1) and then with engine running (12.1). I pulled this from behind the green circuit board in the fuse center under the driver side, front of coach...but now I'm not sure if it's the battery disconnect or the solenoid...




As you can see in this next picture, there is a button on the board that says to push it and listen for a click to test the aux start (I'm assuming this is talking about the solenoid??) but when I push it, I don't hear anything. I don't see anything else in this compartment that looks like a solenoid...




We are leaving on a long trip in a few days, so I need help quickly! Thanks in advance!

[CA_Traveler]

BTW Your solenoid picture appears to be a flooded battery compartment and the batteries produce corrosive fumes - Not good for all of the nearby electronics, etc. You might want to clean the area not that it will prevent the fumes.

[CA_Traveler]

This - Engine on/no Gennie: 12.6 - indicates the house battery is not being charged by the alternator PROVIDED you waited several minutes for any electronic time delay.

Moffittclan wrote:
can I jumper from the battery directly to one of the smaller terminals to test the solenoid? If I understand them correctly, applying voltage to one of the small terminals (the one NOT the ground) should engage the solenoid and I should hear it click...If it does click, then my problem would be somewhere else (like the ignition sensing circuit or something)???

Sound about right?

Clicking is a good sign but DOESN'T mean there is electrical contact. A common failure is pitted/corroded contacts inside the solenoid. The solenoid requires continual power to engage and either your alternator or charger provide that power. It's also common for the charger to NOT charge the chassis battery and the solenoid remains off on shore power.

FYI The bottom part of your latching relay (your first picture)
is a second small relay. It is set up to mechanically latch the main relay. A pulse changes between on and off and then it draws no further amps. Exactly what you want - no amps used to keep it on.

[MEXICOWANDERER]

The more insanely complicated a circuit is the more insanely aggravated the owner will become with frequent breakdowns. Exposed wiring is bad Juju. A harness is vulnerable as are exposed logic circuits.

This is about as simple and reliable as it gets. One positive cable from the chassis battery. One positive cable from the house battery, a short 16 gage ground wire and the unit works. Want pushbutton over-ride? Run a wire to a dash switch. For that I use a 12 gage for mechanical strength. XXL cross link 12-gage is damned near indestructible. When you are fighting your 5th episode with OEM garbage this little combiner will be looking at the sky whistling a tune of uncaring smirk.

[Chris_Bryant]

Moffittclan wrote:
can I jumper from the battery directly to one of the smaller terminals to test the solenoid? If I understand them correctly, applying voltage to one of the small terminals (the one NOT the ground) should engage the solenoid and I should hear it click...If it does click, then my problem would be somewhere else (like the ignition sensing circuit or something)???

Sound about right?

Yes- I would certainly disconnect the wire on it, then jumper it, though on the schematics I found the aux start switch does just that- jumps full power to the relay (solenoid).

[Moffittclan]

can I jumper from the battery directly to one of the smaller terminals to test the solenoid? If I understand them correctly, applying voltage to one of the small terminals (the one NOT the ground) should engage the solenoid and I should hear it click...If it does click, then my problem would be somewhere else (like the ignition sensing circuit or something)???

Sound about right?

[Chris_Bryant]

Moffittclan wrote:

Chris Bryant wrote:
That is the right solenoid. The only other test is voltage at the third small terminal- could have two small terminals, one would be ground then. That is an intermittent duty solenoid, but the controller cuts the hold voltage down, so you won't get full voltage at the small terminal all the time.

Small terminals had about .6 volts on each I think...might have to check again in the morning...what should it be?

One should have somewhere above 6 volts I believe- they do cut the voltage down after it engages, but the other should have 0 on it- I'm 90% sure one needs to be ground.
That other relay would work in a pinch- it's rated at half or less the current your present one is, so it would not be long lived, though if you kept the batteries up so it never had to do 200 amps it would be fine.

[gatorcq]

Yes, that BCC has an Internal B.I.R.D. Which will tell the relay to open and close. Connect is at 13.5, disconnect is at 12.8.

So, you can goto the Intellitec web site and download the manual.
There might be 2 located under the board. One could be the battery disconnect relay for storing the coach. If there is another that might be the you are looking for.

My BCC has 2.

[MrWizard]

what is the amps rating of the contacts ?
i did not see it listed
yes it will fit but will the contacts carry the max charging your alternator can do, if the batteries are low

but you don't know that the original is bad
a new one won't work if there is NO voltage on the terminals

[Moffittclan]

Will this one (or similar) from the auto parts store work as long as it's 12v and rated for continuous duty?

[Moffittclan]

Chris Bryant wrote:
That is the right solenoid. The only other test is voltage at the third small terminal- could have two small terminals, one would be ground then. That is an intermittent duty solenoid, but the controller cuts the hold voltage down, so you won't get full voltage at the small terminal all the time.

Small terminals had about .6 volts on each I think...might have to check again in the morning...what should it be?

[Moffittclan]

Chris Bryant wrote:
That is the right solenoid. The only other test is voltage at the third small terminal- could have two small terminals, one would be ground then. That is an intermittent duty solenoid, but the controller cuts the hold voltage down, so you won't get full voltage at the small terminal all the time.

Small terminals had about .6 volts on each I think...might have to check again in the morning...what should it be?

[Chris_Bryant]

That is the right solenoid. The only other test is voltage at the third small terminal- could have two small terminals, one would be ground then. That is an intermittent duty solenoid, but the controller cuts the hold voltage down, so you won't get full voltage at the small terminal all the time.

[Moffittclan]

I think I found the charging solenoid in the back of the battery compartment...




The right terminal comes from chassis battery and the left comes from the house battery. Here's what I get with a volt meter:

Right terminal (Chassis battery):
Engine off/no Gennie: 12.9
Engine on/no Gennie: 13.9
Engine on/Gennie on: 13.9
Engine off/Gennie on: 13.08

Left Terminal (house battery)
Engine off/no Gennie: 12.6
Engine on/no Gennie: 12.6
Engine on/Gennie on: 13.38
Engine off/Gennie on: 13.38

Another symptom, pushing the boost button on the dash doesn't seem to do anything. I tried putting it in "store mode" then turning on a light...nothing happened of course, but I thought if I pushed the boost button, I would see a light come on...nothing happened. Also, when I had bad chassis batteries a while back, the boost didn't do anything...

I can't find any blown fuses....does this mean that what I've found is in FACT the charging solenoid and based on these readings, it needs replaced?

[Moffittclan]

I was getting 12v on the right side pole but for some reason, after I've reinstalled it and connected everything back up, I get either 0 or sometimes between 1 to 4 volts...it's really weird. Also, after I first put it all back together, the coach wouldn't start...it would turn over but not start...like it want getting gas. I disconnected and reconnected batteries and now it starts but still not getting any voltage on either pole of the BDS. Everything appears to be working in the coach for now but not having voltage on this switch is troubling...