One more BIRD / Trombetta issue

[Travbob]

2016 Vegas 25.2 with a very intermittent issue (has happened 3 times in two years). It has the potted Intellitec BIRD and Trombetta solenoid. Each time the symptoms have been identical. When parked with switch in store position and not plugged in, both coach and chassis batteries have gone dead. The coach batteries are around 11 volts but the chassis battery is at 2-2.5v. I know it takes about a week for the batteries to go dead but always the chassis is completely dead and the coach not so much (I could start the gen-set the last time, but barely).

The only theory I can come up with is that the BIRD is not taking power off the Trombetta closing coil. Thus when I shut down the engine the Trombetta remains closed linking the coach and chassis batteries. This is made worse by the fact that Thor wired the ignition feed to the BIRD from the main lug on the Trombetta so it is powered even with the key off. And the lug connected to the coach batteries is always live (the use/store switch does not affect it). I am not sure where the coach battery sensing line to the BIRD comes from but it is supposed to be isolated by the use/store switch.
So when I park the unit the voltage on the batteries is high enough for the BIRD to keep putting power to the Trombetta (as it should with this wiring arrangement). However "sometimes" the BIRD is not dropping out the power to the Trombetta when the voltage drops to 12.7v as it should. The drain on the system is the Trombetta's closing coil which pulls about .75amps. From information about the Tombretta at around 10v the coil is not strong enough to hold in the main contacts so it drops out and thus isolates the coach and chassis battery (this would explain why the coach batteries are around 11v). However since the BIRD is connected directly to the chassis battery if it did not drop out the coil it would continue to draw current from the chassis battery until it is completely dead. At that point the BIRD resets and everything is back to normal when I look for parasitic load (on both sides it is milliamps which would take months to drain the batteries)

So has anyone else ever seen a BIRD fail this way? Anyone got a different theory or ideas? Everything points to the BIRD but it is so infrequent I am not sure. Is the fact that there is power to the BIRD always (Intellitec installation instructions say to wire it to the downstream side of the Ford solenoind so when the key is turned off, sensing power to the BIRD is off) have any impact? By the way most times the unit sits for a month or more and all batteries stay at full charge so it is not batteries or a constant parasitic load.

[Oneilkeys]

That is weird. I agree with your analysis on the BIRD intermittently not turning off the Trombetta, but from my experience I would think that it would be the coach batteries that discharge to nothing while the chassis battery would stay at 11V. Even with the use/store in store, Unless I hit the 100 amp breaker in the battery box, my coach batteries quickly discharge while the chassis battery discharges much more slowly. I can still start the coach after several weeks or more not being plugged in. By that time, my coach batteries would be dead. Since it happens so infrequently, it is very difficult to diagnose. One diagnosis you could try would be to open the 100 amp breaker in the battery box and see what happens. If the chassis battery still discharges quickly down, then it would indicate a problem at that end. The only other thing that I could suggest is that you monitor the voltages in the coach and chassis batteries to see if the Trombetta opens to disconnect them at the correct voltage. Since it happens so infrequently, it might take a long time to see anything. However, if the Trombetta is disconnecting at something different than 12.6, that would indicate something wrong with the BIRD or Trombetta - most probably the BIRD. The BIRD in my Axis was wired incorrectly at the factory so the coach batteries did not get charged by the alternator. But I cannot see how that can be the case with your problem.

[Travbob]

Originally Posted by Oneilkeys

That is weird. I agree with your analysis on the BIRD intermittently not turning off the Trombetta, but from my experience I would think that it would be the coach batteries that discharge to nothing while the chassis battery would stay at 11V. Even with the use/store in store, Unless I hit the 100 amp breaker in the battery box, my coach batteries quickly discharge while the chassis battery discharges much more slowly. I can still start the coach after several weeks or more not being plugged in. By that time, my coach batteries would be dead. Since it happens so infrequently, it is very difficult to diagnose. One diagnosis you could try would be to open the 100 amp breaker in the battery box and see what happens. If the chassis battery still discharges quickly down, then it would indicate a problem at that end. The only other thing that I could suggest is that you monitor the voltages in the coach and chassis batteries to see if the Trombetta opens to disconnect them at the correct voltage. Since it happens so infrequently, it might take a long time to see anything. However, if the Trombetta is disconnecting at something different than 12.6, that would indicate something wrong with the BIRD or Trombetta - most probably the BIRD. The BIRD in my Axis was wired incorrectly at the factory so the coach batteries did not get charged by the alternator. But I cannot see how that can be the case with your problem.

Some good thoughts there, thanks.
In my case the BIRD is wired permanently and directly to the chassis battery so if the BIRD is energizing the Trombetta ,once it drops out all the load has to come from the chassis battery and so it would go completely dead. The coach batteries are slightly protected by the Trombetta not being able to stay closed with very low voltage.

Right now have charged all batteries and the BIRD has again closed the Trombetta. I will let both battery voltages drop to try to see if the BIRD drops out and at what voltage. The risk is that this happened so rarely that it might not show. If it happened every time it would be easy to troubleshoot. I guess I could just bite the bullet and replace the BIRD but I hate just changing parts unless I know for sure that is the problem.

[Oneilkeys]

I’m not sure I understand your comment that the BIRD is wired directly to the Chassis battery. It is supposed to be wired to the ignition switch, so that the BIRD is only powered by the chassis battery when the ignition is on.

The following is from the BIRD instructions.
“When the ignition switch is turned on and the engine is running, the system senses the level of voltage on the chassis 12 volt system. When this voltage goes 13.1 volts for approximately 2.5 minutes, as happens when the engine is running normally (normal alternator output voltage of a cold engine is approximately 14.4 volts), it will close the isolator relay providing charging current to the battery. This delay allows a cold engine an opportunity to start and warm up before having the heavy load of a discharged coach battery placed on it.

If the voltage should fall 12 volts for more than about 1 minute, the relay will drop out to feed all the alternators available output to the chassis battery to keep the engine running. This might happen when the alternator is not able to supply sufficient current to all of the loads and charge the coach battery at the same time. When the chassis voltage goes 13.1volts again, the relay will again close in about 2.5 minutes to retry to charge the battery.”

So when you turn the key off, the BIRD is no longer connected to the chassis battery.

Also from the instructions:
“If the voltage should fall 12.6 volts for more than about 1 minute, the relay will drop out to prevent the coach loads from discharging the chassis battery.”

So the system is designed to separate the two banks when the voltage drops below 12.6v so that the chassis battery will not discharge into the coach battery or the other way around. There is no way that the BIRD can discharge the chassis battery once the ignition is turned off - if it is installed and working correctly.

[Travbob]

Originally Posted by Oneilkeys

I’m not sure I understand your comment that the BIRD is wired directly to the Chassis battery. It is supposed to be wired to the ignition switch, so that the BIRD is only powered by the chassis battery when the ignition is on.

The following is from the BIRD instructions.
“When the ignition switch is turned on and the engine is running, the system senses the level of voltage on the chassis 12 volt system. When this voltage goes 13.1 volts for approximately 2.5 minutes, as happens when the engine is running normally (normal alternator output voltage of a cold engine is approximately 14.4 volts), it will close the isolator relay providing charging current to the battery. This delay allows a cold engine an opportunity to start and warm up before having the heavy load of a discharged coach battery placed on it.

If the voltage should fall 12 volts for more than about 1 minute, the relay will drop out to feed all the alternators available output to the chassis battery to keep the engine running. This might happen when the alternator is not able to supply sufficient current to all of the loads and charge the coach battery at the same time. When the chassis voltage goes 13.1volts again, the relay will again close in about 2.5 minutes to retry to charge the battery.”

So when you turn the key off, the BIRD is no longer connected to the chassis battery.

Also from the instructions:
“If the voltage should fall 12.6 volts for more than about 1 minute, the relay will drop out to prevent the coach loads from discharging the chassis battery.”

So the system is designed to separate the two banks when the voltage drops below 12.6v so that the chassis battery will not discharge into the coach battery or the other way around. There is no way that the BIRD can discharge the chassis battery once the ignition is turned off - if it is installed and working correctly.

I agree with you completely since I came across the same instructions on the Intellitec site. However, that is not what Thor did on this unit. The "ignition connection" is wired to the large right lug on the Trombetta and this lug is connected directly to the chassis battery. Thus it is hot all the time. I have seen one other picture of a Trombetta on this site and can see the wire leading from the battery lug to the BIRD the same as mine. It is not right but it seems Thor did it that way at least twice. So the ignition key position has no effect on power to the BIRD.

IF the BIRD is working properly it should open the Trombetta and separate the coach and chassis batteries but from the symptoms it appears that it is not. Thus the BIRD, if it is faulty could pull down both the coach and chassis batteries until the Trombetta drops out due to low voltage and then go on to drain the chassis battery completely.

I think no mater what the condition of the BIRD I will rewire it so it is on a keyed power supply as Intellitec suggests in their instructions. This would prevent the BIRD from draining the chassis battery but again the BIRD has to be faulty for this to happen unless it not designed to be powered permanently. I have no way of knowing if Thor wired all the Vegas's that way or just mine and a few others.

[Oneilkeys]

I guess it doesn’t surprise me that some Thor “technicians” install the BIRD any way that is easiest for them. It’s a much shorter wire run from the BIRD to the Trombetta than to the ignition coil. In my case, the “technician” ran the BIRD wire to the coach batteries “somewhere”. I never figured out where, but it was not to the coach batteries so the BIRD never got the correct voice outage from the coach batteries. I fixed it by cutting that wire, adding a fuse, and attaching it to the coach battery side of the Trombetta.
In your case, the BIRD is “hot” all the time. I wonder if that is good for it. On the other hand, I do not see why the BIRD should discharge the chassis battery even hooked up incorrectly. The BIRD only opens and closes the Trombetta and if the Trombetta is open, both battery banks will equalize. If it is closed, then neither battery bank should be affected by the BIRD - especially infrequently.
When I had my problem, I finally called the people at Intellitec and they we very helpful in working me thru my issue and giving me enough courage to just cut the wire and reinstall it. I think you may be at that point. I wonder what if wiring the BIRD directly to the battery Has damaged it somehow. Before I installed a new one (and i’m Not positive that will solve your problem) I would make sure that installing the new one that way is a good idea.

[Travbob]

Originally Posted by Oneilkeys

I guess it doesn’t surprise me that some Thor “technicians” install the BIRD any way that is easiest for them. It’s a much shorter wire run from the BIRD to the Trombetta than to the ignition coil. In my case, the “technician” ran the BIRD wire to the coach batteries “somewhere”. I never figured out where, but it was not to the coach batteries so the BIRD never got the correct voice outage from the coach batteries. I fixed it by cutting that wire, adding a fuse, and attaching it to the coach battery side of the Trombetta.
In your case, the BIRD is “hot” all the time. I wonder if that is good for it. On the other hand, I do not see why the BIRD should discharge the chassis battery even hooked up incorrectly. The BIRD only opens and closes the Trombetta and if the Trombetta is open, both battery banks will equalize. If it is closed, then neither battery bank should be affected by the BIRD - especially infrequently.
When I had my problem, I finally called the people at Intellitec and they we very helpful in working me thru my issue and giving me enough courage to just cut the wire and reinstall it. I think you may be at that point. I wonder what if wiring the BIRD directly to the battery Has damaged it somehow. Before I installed a new one (and i’m Not positive that will solve your problem) I would make sure that installing the new one that way is a good idea.

Thanks for the info and I think I have two issues. The first is that Thor wired the BIRD incorrectly and I am not sure what impact that has unless the BIRD malfunctions. Second even with the current wiring there must have been an issue with the BIRD since 99% of the time the system works as it should. By the way would you happen to know where Thor connected the "ignition" wire from your BIRD?.

Just as a note I see we are using different terminology. When I say the Trombetta is closed, I mean the coil is pulled in and it has closed the circuit. In this case that connects the chassis and coach batteries.

[Oneilkeys]

Sorry. I do not where the BiRD wire for the ignition wire is actually attached. It goes into a harness and into the engine. For the coach battery wire, I was able to cut it before it went into the harness and then attach it directly to the Trombetta. If you can get to the ignition coil, you might be able to do the same thing.