Long standing issue with Intellitec BIRD/Big Boy

[distaff]

I've had a number of problems with my charging system. It now is down to this:

• On generator power both the coach and chassis batteries are charging
• On engine power (alternator) both coach and chassis batteries are charging
• On shore power (in the case I observed it was on 30 amp) the coach batteries charge and the chassis batteries do NOT charge.

I am assuming that while the chassis batteries provide the starting power to the genset, the generator does NOT provide 12 charging to the batteries directly as the engine alternator does. I am assuming that the genset provides 110v to the inverter and it provides the charging power to the coach batteries, and the Bird/Big Boy system closes the cross over system to charge the coach batteries.

I was plugged into shore power all week and my coach battery voltage kept drifting down, but on genset power and with the engine running everything was happy. I've attached the wiring diagram if anyone can read it (I'm a little weak on these things).

Any ideas?

[Steve Ownby]

It's hard to understand how there is a difference in function at the Big Boy between shore power & generator power. My understanding is the BB control circuit board receives the same input signal regardless of the source of 120 vac power. Here is a write up I received on this subject from a coach owner who studied the BB system in depth.

Quote:

Your coach has the same BB system as mine. The Big Boy Relay is controlled by Bird Relay which is located in the RRB. It is located on the right side and is the third circuit board from the top. There is a Green LED-(ISO Relay On)-third from the top on the board that should be Illuminated and the Big Boy Relay should have a low humm and be hot to touch when working properly.

When you disconnect from shore power and the generator is not running, the Green LED should be out. The Big Boy Relay will drop out of the circuit when the dc voltage drops to 12.5 to 12.8 vdc when measured at the Battery side of the Big Boy Relay.

When connected to shore power or when the generator is running you should have power to the #2 pin on the eight pin connector on the right side of the board. The #1 pin is ground and the #3 pin is powered on when you turn on the Ignition Switch. Pin #4 is from the battery boost circuit, Pin #5 is the Domestic power circuit. Pins #6 & #7 are blank. Pin #8 is a ground circuit.

The six pin connector on the top of the board powers up the relays. The left pin is Pin #1 and is ground, Pin #2 powers up the Big Boy Relay, Pins #3-4-5-6 power up the two Domestic Relays to the right of the Big Boy Relay. When working properly you should measure about + or - 4.6vdc on Pin #1 when the Board is powered up and the Big Boy Relay is working.

If the BB is powered up and running correctly, you should have around 4.5 to 4.8 vdc on pin 1 of the 6 pin connector. You should also have that same voltage on pins 1, 4, 5 & 8 on the 8 pin connector.

On the BB Solenoid you should be seeing 12.8+ vdc on the chassis side battery post-(left side) and 13.0+ vdc on the house battery side post-(right side). A differential of .3 to .6 vdc between these two posts is normal.

If your Inverter is set up correctly and the Bird relay is working-(green light on) the Inverter through the BIRD Relay and the BB will charge the Coach Batteries first and then the Chassis batteries and when all the Batteries are fully charged the Inverter will go into float charge. When plugged into Shore Power or with the Genset running the Green LED will be Lit on the BIRD Relay Circuit Board, If not I would venture to guess that the circuit board is failing or has failed. The relay above the eight pin connector on the BIRD circuit board controls the Big Boy Relay, it could be failing.

"Happiness Is The Journey, Not The Destination"

David & Sandy Pratt, Melbourne FL

[bgbranch]

Originally Posted by distaff

I've had a number of problems with my charging system. It now is down to this:

• On generator power both the coach and chassis batteries are charging
• On engine power (alternator) both coach and chassis batteries are charging
• On shore power (in the case I observed it was on 30 amp) the coach batteries charge and the chassis batteries do NOT charge.

I am assuming that while the chassis batteries provide the starting power to the genset, the generator does NOT provide 12 charging to the batteries directly as the engine alternator does. I am assuming that the genset provides 110v to the inverter and it provides the charging power to the coach batteries, and the Bird/Big Boy system closes the cross over system to charge the coach batteries.

I was plugged into shore power all week and my coach battery voltage kept drifting down, but on genset power and with the engine running everything was happy. I've attached the wiring diagram if anyone can read it (I'm a little weak on these things).

Any ideas?

The difference between generator power and the 30 amp shore power you were using at the time is that 1/2 of your 120 volt system was powered down.
Try it plugged into 50 amp shore and see if it charges your chassis batteries.

[Gorlininc]

The BIRD treats the generator and shore power a little different.
There is a wire on the BIRD labeled GEN. I'm not exactly sure the difference but there is. I know you can run the BIRD without that connection. Is try removing that connection and see if your shore power charges.

[Carl & Shelly]

I too have had problems with the big boy relay, I was able to repair them myself, My BB relay would make noise but not allow currrent to flow, the contacts were corroded because
of the way it is mounted. Cleaned the contacts and all is good, if confused give me a call 503-391-6300 and I will explain!
Carl

[distaff]

Thanks - it is not a Big Boy problem, the Big Boy works under 2 of the 3 scenarios. I will spend some time with again next week with my multimeter when the weather improves, but I don't have access to a 50 amp system, or even a 30 amp for that matter.

[Steve Ownby]

Originally Posted by distaff

Thanks - it is not a Big Boy problem, the Big Boy works under 2 of the 3 scenarios. I will spend some time with again next week with my multimeter when the weather improves, but I don't have access to a 50 amp system, or even a 30 amp for that matter.

So long as you have 120 vac power coming in on the shore cord through a standard adapter, you should be able to test the system. If 15-20 amp you will have to make sure most everything in the coach is off and the inverter set to a fairly low level for battery charge. If your coach has the fairly standard Monaco rear run box, there will be a circuit board mounted over at the right side of the box that controls the BB. It will have a green light on it which will be lit when the BB is running. It also has two yellow test buttons. If your coach is a later one with multiplex I'm not sure if any of this applies.

When the BB engages you will hear two clunks a second or two apart. Then you should see a voltage on each of the large bottom lugs of something over 13 VDC. They should be within 0.5 volt of each other. I believe the left lug is chassis and right lug is house. When shore power is on the house batteries will be receiving the charge from the inverter. In the situation you describe if you see 13.3 or higher on the house battery terminal and around 12.6 or less on the chassis side then the control circuit board is tango uniform. Monaco will sell you a circuit board for around $130 and can tell you if you need an adaptor. If your current circuit board has an 8 pin connector on the right edge of the board then you don't need the adaptor.

[YC1]

Originally Posted by distaff

Thanks - it is not a Big Boy problem, the Big Boy works under 2 of the 3 scenarios. I will spend some time with again next week with my multimeter when the weather improves, but I don't have access to a 50 amp system, or even a 30 amp for that matter.

Solenoids can become intermittent and you may be tricked. The contacts can become intermittent and the vibration from the engine running or the generator running might be enough to give you your symptoms.

In any case, a solenoid is a very simple device to troubleshoot. If the control voltage and ground are on the small control contacts the solenoid should be functioning,. If it is not it needs to be replaced or overhauled. These solenoids work hard and are a common failure item. There are hundreds of pages you can search on if interested.

I have replaced mine twice. Think of it this way. A set of fuel filters cost more than the solenoid in most cases. Why not just replace it and end the frustration. If your engine ran rough you would not hesitate to replace the fuel filters.

[KevinM in FL]

This discussion has now got me curious about my BIRD relay (04 Dynasty), particularly when the green LED light should be illuminated. I have had the coach parked at my house for the last six months plugged into 50 amp shore power. The charging system is in float charge mode, but the green light is not illuminated, at least when I've checked a couple of times.

However, all the house and both chassis batteries are fully charged, so it must be working correctly. I would think the phantom drain on the chassis batteries would have discharged them to some degree during this time if they were not being charged, no? My point, I guess, is that the BIRD relay does not appear to stay illuminated when the batteries are fully charged and the inverter is in float charge mode, at least for my system. Is this incorrect? Kevin

[distaff]

Steve,

You are mostly correct in describing my implementation, except no test buttons and no LED. On mine there are two small relays mounted on a metal bracket directly over top of the BIRD unit, and the whole thing is tucked behind the tail light assembly, so it is a real pig to work on.

I have tested it with the multi meter and the first problem I was having was pretty simple because the boost switch didn't work either - so it was the common relay that connected the BIRD output and the boost switch to the Big Boy.

YCI - I like your thinking but I'm not optimistic that it is vibration related - the Big Boy responds correctly to the boost switch with both Genset and motor off, so I'm pretty sure it is working normally. BTW - a replacement Big Boy is about $300. So no, I'm not in a rush to replace it. I do have the instructions Mike Canter circulated on how to take it apart and clean it, and I may do that just as a routine preventative maintenance.

This problem has been going on for some time, it was concealed by the failed relay before, now I have to dig a little deeper to find the cause. I may just bite the bullet and buy an new BIRD unit. I just hate doing that kind of diagnosis - keep buying new parts until you finally fix it.

[YC1]

Have you measured the voltage across the small terminals under all of those conditions? If that schematic is accurate it appears it may use full voltage to engage the solenoid and then reduce the voltage to hold it in. Using a digital voltmeter could easily fool you so use an analog meter if possible. Sure seems like a lot of money for a solenoid. I'm curious what the part number is.

One test is to measure the voltage across the big terminals under all of the conditions. It should be 0 or very close when the solenoid is engaged. To do this test turn on the dash AC fan, headlights, and whatever else you can use to load the engine battery down. Do not run the engine for this part of the test. Trying to get a load across the solenoid contacts to see if there is an IR drop. (voltage across resistance).

[YC1]

Any chance you can take a picture of the relay and post it? Just in case that schematic is not for your model.

[distaff]

I'm pretty sure it is correct, I've been over it more than once, but I'll try and get one posted tomorrow. Have to go to the coach to retrieve some tools (wife's Volvo developed a second broken spring).