Charging Question

[ELeland]

My last long trip I had to run the generator occasionally to keep the house batteries from dropping too low.  Shouldn't they receive a charge from the chassis side while the engine is running?  Another observation was several months ago when the chassis batteries died, the Auxiliary Start switch did not work.  I've read these two issues may be related.  Solenoid?  Where is it located and how do I test it?  It's a Freightliner XC Chassis

Thanks

Ed

 

[Gary RV_Wizard]

Yes, the battery isolation solenoid is involved with both those functions.  It normally keeps chassis and house 12v systems isolated from each other. but cross-connects them for charging from the alternator or when the Aux Start switch is held down (on).  It is supplied by the coach builder, not Freightliner, so we don't know where yours is located.  Typically in a Class A it is near the house batteries and may be part of or wired directly to a Battery Control Center (BCC) module. Hopefully another Airstream owner has already found his and can give advice.

 

[ELeland]

Thanks Gary.  Is it a 2 pole solenoid?  I do see one in the battery bay.  One side is attached to the + terminal of the chassis battery, not sure where the other end is fed.

I do have all the manuals and wiring diagrams, but don't know what I'm looking for.  See attached chassis diagram from the manual.

Ed

 

[Gary RV_Wizard]

Most coaches have two solenoids, one for a house battery disconnect and one the isolation solenoid I described.  Since it connects to the chassis battery, sounds like you found the isolator.  Per the diagram, the chassis battery connects to the Intelletec BCC - is that where the solenoid is located? Some BCC have the solenod integrated,while others mount them externally.

 

[CJAG]

I need help with this also. Gary I tried to start my rig today with the button on the dash. I turned the key on and pushed the button. I heard what sound like elect current but I got nothing to start the motor. Is this possibly the solenoid and that is why my battery wont house batteries wont charge when the engine is running?

 

[CJAG]

OK i found a few posts on this. My chassis battery is charged so how can I test the solenoid with Chassis battery full?

 

[ELeland]

Thanks again Gary.  Here is a pic of the BCC with the cover off.  The solenoid I referenced earlier is stand alone in the battery compartment (also a pic).  The BCC is in the adjacent bay away from the corrosive environment.  I'm not sure which or what to test or change out.  It's above my pay grade....

Suggestions?

 

[Alfa38User]

OK i found a few posts on this. My chassis battery is charged so how can I test the solenoid with Chassis battery full?

It should make little difference, you can still try the start procedure but the correct functioning will not be easily detected without looking at the relay itself.
OR:
With the RV unplugged, start by putting a voltmeter across the house battery terminals and take a note of the reading. Start the engine and then go and take another reading. If you read less than 13.5 Volts or so, the battery is not charging and the relay has not operated as it should.  The "why" and further testing will depend on what systems you have in your Coachmen RV for this function.

 

[CJAG]

I have 2-6 volt house batteries and my reading is 6.7 volt

 

[Alfa38User]

Your 2 batteries must be wired in series to give 12Volts. You have to measure across the positive of one and the negative of the other to read 12.x volts

If this is not the case, your house batteries are not wired correctly or you will have to get some additional electrical help to figure this one out.

 

[CJAG]

OK I am anew owner. So measure by touch negative on one battery and positive on the other to get true reading right? Umm that makes sense. I miss the simple things I swear.

 

[ELeland]

I guess my thread got hijacked, but, here is a pic of the 2 pole solenoid that has no part numbers, only labels "AUX" and "BAT" on the terminals.  There is no continuity between the terminals.

Bad, replace?  If so, what do I get to replace it?

 

[Old_Crow]

That't not a solenoid, it's a self-resetting circuit breaker.

 

[ELeland]

That't not a solenoid, it's a self-resetting circuit breaker.

Thanks Old Crow, I did say this was above my pay grade.  Any idea what it might be for?

 

[ELeland]

I cleaned the rust off and see it has 30 A etched in it.

 

[ELeland]

I just picked up a new 30 A breaker at the auto parts store and installed it.  The new one has continuity across the terminals so I fixed something, but just don't know what yet.  :-\

 

[Gary RV_Wizard]

so I fixed something, but just don't know what yet.  :-\

LOL! Any progress is Good!
I'm surprised that breaker is labeled wit Bat & Aux, though.  Since a breaker simply goes in-line in a circuit, it doesn't really have any designation for the two terminals.

I see a solenoid peeking out from behind the circuit board in the BCC, so that's probably it. I would not be too quick to conclude the solenoid is defective - it could be the BCC is not telling it to engage, either because it is not seeing the proper conditions or because of a defect. For example, if the chassis batteries don't reach a certain voltage (usually 13.3v), the BCC will never cause the solenoid to close.

You can read an Intelletec BCC service manual at the link below. It's not the exact same model as yours, but they all work very much alike so the info is useful.http://www.alfaleisure.net/wiki/_media/companies:intellitec:intellitec-service-manual-bcc-min-diesel.pdf

Do you see a model number anywhere on the BCC, something like 53-000769 or 53-000861?  It would help to know exactly what BCC you have.

 

[Lou Schneider]

LOL! Any progress is Good!
I'm surprised that breaker is labeled wit Bat & Aux, though.  Since a breaker simply goes in-line in a circuit, it doesn't really have any designation for the two terminals.

It's marked that way so the battery is on the non-moving side of the disconnect mechanism.  Less chance of the battery shorting to the breaker's grounded case if something fails internally.

 

[Gary RV_Wizard]

Right, but rare is it that a breaker is designed solely for circuits that have batteries in them.  Look through the numerous brands of 12v breakers online and you won't find many that have any markings at all on the terminals.  Would you expect to find another breaker that is labeled for use with "converter" instead of battery? 

 

[CJAG]

I will start a separate post.