Coach batteries not charging

[Peter Becker]

2006 Patriot Thunder.
Was told by a RV mechanic that the Big  Boy solenoid was bad.
Installed a new one today.
Not getting 12 volts at the coil to pull in.
Charges fine with generator.
The inverted was just replaced before I bought the MH.
Any chance the inverted not set properly?
Thanks,
Pete Becker

[David T. Richelderfer]

My opinion and others will correct me if in error:

The Big Boy/BIRD system is a bi-directional system.

If the generator (or shore power) charges the coach batteries, then the inverter/charger (be it a Magnum or Xantrex) is working properly.  If the chassis batteries are getting charged by the alternator on the engine, then the alternator is working properly.

The Big Boy/BIRD system allows the alternator to charge the house batteries after the chassis batteries get charged.  Conversely, the Big Boy/BIRD system allows the inverter/charger to charge the chassis batteries after the house batteries get charged.  The threshold voltage is about 13.2v to 13.3v to make the Big Boy/BIRD system work.

If the Big Boy/BIRD system is "broke," an example being the Big Boy solenoid is not functioning, then the Big Boy/BIRD system will not allow bi-directional charging of both battery banks from either side, that being the alternator or inverter/charger.

Does this make sense?

[Gerald Farris]

Peter,
David is correct about the battery charging sequence for your chassis and house batteries. You said that the house batteries charge fine with the generator, and therefore they should be charging with shore power also. That means that your inverter is operating correctly.

So apparently your problem is that the house batteries do not charge with the engine alternator, correct? If so, it sounds like your "BIRD" controller is not functioning or you have a wiring problem. When your charging voltage reaches the programed threshold, the "BIRD" controller should send a 12 volt pulse to the "Big Boy" solenoid to engage it and then reduce the voltage to it the 6 to 8 volt range to keep it engaged. The voltage reduction is necessary because the "Big Boy" is not a continuous duty solenoid and it will overheat and fail if you use 12 volts to keep it engaged, but it will stay engaged with the reduced voltage after the initial 12 volt pulse without failing.

Gerald

[Peter Becker]

Gerald,
Can you explain what the Bird controller is and
   where would I find It.
Thanks,
Pete Becker

[David T. Richelderfer]

In our Marquis, the Big Boy solenoid is located above the house batteries behind a door where the big fuses (200 amp, 150 amp, etc.) are located.  The BIRD module (black, about 4"x4"x1") is affixed to the back of that same door.

BIRD -  Bi-directional Isolator Relay Delay...  Thus, the bi-directional nature of the cross-over charging system.

[Gerald Farris]

Peter,
I am not sure exactly where your "BIRD" controller is located, but probably where David described. Here is a picture of the unit;  https://www.intellitec.com/index.php/products/DC_Power_Management/Intelligent_battery_charging/The_BIRD

A word of caution, never just start throwing parts at a condition before you diagnose the problem. Like, why would any mechanic say that the "Big Boy" is bad if there was no current going to it to activate it. You can not condemn a solenoid as defective that has no electric current to activate it.   

Gerald

[Peter Becker]

Found the Bird controller.
Have 12VDC to all terminals except to
   the solenoid.
Any ideas?
Chasis battery @ 14.1, coach batterys @ 12.6
Thanks,
Pete

[Gerald Farris]

Peter,
Since you list the chassis battery voltage at 14.1 volts, the engine should be running and charging them with the engine alternator. Therefore the "BIRD" controller should be sending voltage to the "Big Boy" to enable the charging of the coach batteries, but it is not. So it should be easy to determine why by reading this pdf that includes the wiring schematic. https://www.intellitec.com/assets/pdf/1453-intellitec-pdf-template-53-01000-000.pdf

Gerald 

[Peter Becker]

Got back to storage lot today and got the following readings.
With gen on
Ignition 0.0
Battery 14.8
Solonoid 10 VDC
Big Boy not closing. 14.8 on chasis side, 12.6 on coach side, but coach battery seems to charge.

Engine on
Ignition 14.15 VDC
Battery 12.73
Solonoid 9.5
Big Boy readings same as above. Coach battery not charging.
Jumpered + side on Big Boy with a 16ga wire and it melted within a few seconds.
Any ideas?
Thanks,
Pete

[David T. Richelderfer]

Sounds to me like your inverter/charger is not charging the house battery bank.  Does your Aladdin, Silverleaf, or inverter/charger remote panel show the house battery bank is getting charged?  It also sounds like your Big Boy/BIRD system is not working correctly.

The generator through the inverter/charger should be charging your house battery bank regardless if the Big Boy/BIRD system is working or not.

On the other hand, your engine alternator should be charging your chassis battery bank regardless if the Big Boy/BIRD system is working or not.

Once either battery bank gets fairly well charged, be that the house battery bank charged by the inverter/charger or the chassis battery bank charged by the engine alternator, then the Big Boy/BIRD system should allow the charging current to cross over to charge the other batteries.  Remember the bi-directional nature of the BIRD.

Alternator >>> chassis batteries  <><><>BIRD<><><> house batteries <<< inverter/charger <<< generator

[Peter Becker]

As I stated earlier, a new inverted was install at the time
   I purchased the MH.
Could this be set up improperly?
Thanks

[Joel Ashley]

I’m not sure Gerald linked to quite the correct Intellitec page as it’s for a gas coach.  I’ll always defer to him, but with respect this may be the one he meant:   https://www.intellitec.com/assets/pdf/1453-intellitec-pdf-template-53-00362-000.pdf
But I note the data sheet/diagram on their site does not match the product shown.  The Club’s Coach Assist section has the correct one I believe:   http://beaveramb.org/wp-content/uploads/2016/11/Bird-Isolator-Diesel-2.pdf

and of relevance is  http://beaveramb.org/Data/PDF%20Manuals/intellitecbigboyandbird/Big%20Boy.pdf

Before going too far along, know that reported on occasion are loose or corroded connectors on the BIRD (probably located on the inside of the Big Boy/fuse compartment access door) that provide enough resistance to befoul the system.  If you haven’t already, a first simple step should be to check for that possibility.  I’ve also learned to be careful closing that door as the wires can get pinched, so check for possibly damaged wires.

Also see that the new inverter is programmed for the type of battery currently installed, wet cell, AGM, etc.

Joel

[Peter Becker]

Still confused.
All connections on Bird are corrosion free.
Big Boy coil has 2 ohms resistance which seems about right.
Unsure why this would melt a 16ga jumper within a few seconds.
Inverter is set to correct battery type.
Cannot get solonoid to pull in from Bird controller.
Thanks

[Gerald Farris]

Peter,
There are a few voltage readings that you posted that do not make sense. First like David said when the generator is running or you are plugged into shore power, the inverter only charges the house batteries without the "BIRD" system, but you stated that the chassis were charging at 14.8 volts and the house batteries were not, and the "Big Boy" was not connected. Unless your coach has been miss wired or you have a very bad battery cable connection and the "Big Boy" is connected, this is not possible.

If you would like help in trouble shooting your coach charging system, call me (713-254-4156). I will be in the Pacific Time Zone for the next 3 weeks.

Gerald   

[Peter Becker]

Had time to recheck things today.
Seem my system is a little different from most.
The solonoid terminal from the BIRD control goes into a plug
   on the side of the rear electrical box. The wire is tagged sol. out.
The solonoid in wire comes from the same plug, but never any voltage (going to the Big Boy).
   on it. Also, right in front of the BIRD controller are 2 relays. I believe they
are single pole, double throw. The left relay has no power to the coil, but the right one does.
When I wired to the Big Boy directly from the Bird controller (solonoid terminal), it only gives 3.3VDC when connected.
When I pulled the wire from the Bird, I get 9.6VDC (without a load).
Very confused.
Thanks,
Pete