Big Boy and BIRD - Learned Something Not in the Documents

[distaff]

I've had some issues with the isolator system - it is intended to charge the chassis batteries when on shore or generator power and the coach batteries when the big diesel is running. A picture of my panel care of Monaco is attached at the end.

First I found that a $6 relay that sits between the BIRD and Big Boy was bad (easy and cheap fix and it worked fine for a year after that). That relay is intended to let either the BIRD or dash Boost Switch close the Big Boy relay. I had spent a fair bit of time trying to get and then reading documentation on how the system worked (including the BIRD, Big Boy, and Monaco supplied wiring diagrams), and I was confident that I had a pretty good understanding of how it worked. I was wrong.

It was acting up again recently, and I started doing some testing and was getting very strange voltage readings - sometimes the inputs to the Big Boy showed 8 to 9 volts, at other times around 3 volts. I pulled the Big Boy and had it bench tested by an electrical engineer working on a project with me, and it was drawing 10 amps when closed! Yikes! That is more than my solar panel puts out. I thought it was supposed to be a latching relay because the only documentation I could get from Intellitec's website said it was, but we took it apart and it has no latching mechanism. It turns out they sell two types that are both called Big Boy, they both look the same, and the only service documentation on Intellitec's website is for the latching version.

The documentation does say it needs 6 amps and 12 volts (10.5 v minimum) to activate, seems mine was a bit hungrier.

I tried Monaco and didn't get much from them, but I finally got in touch with Intellitec's RV support group. It turns out it is an RV electronics company in Ohio City, Ohio. I spoke to Chris who was very helpful and he explained that a bench test will show a high draw, but that the way it really works is that when the BIRD unit decides to close the relay it sends 6 amps and 12v to the Big Boy, and then after a fraction of a second it begins modulating the voltage so that if you read it with a meter you will see around 4 v (on mine I see 3) and you can hear it humming (which mine certainly does). At this point it is sending less than one amp to the Big Boy, but it is enough to keep the relay closed.

He confirmed that you CAN'T use the latching version as a replacement because of the way the BIRD unit activates the non-latching Big Boy. The other thing he confirmed is that when you push the Boost Switch on the dash it sends 12v and 6 amps continuously to the Big Boy, and if you keep holding the switch down beyond 30 seconds you will burn out the Big Boy. The BIRD unit can keep the Big Boy closed for hours without damaging it because of the modulation of the current.

This goes a long way to explaining why I could never make sense of the readings I was seeing. I did have another issue that my Magnum inverter was confused but I have a buddy who is a service dealer for them and he helped me reset it and the whole thing was working fine today.

If you want to see what your system is doing you have to attach a meter with a feature that remembers the high voltage it has seen in order to catch the momentary 12v spike.

[nodine]

Very interesting Paul, thanks for sharing.

Bob

[bruceisla]

Originally Posted by distaff

I've had some issues with the isolator system - it is intended to charge the chassis batteries when on shore or generator power and the coach batteries when the big diesel is running. A picture of my panel care of Monaco is attached at the end.

First I found that a $6 relay that sits between the BIRD and Big Boy was bad (easy and cheap fix and it worked fine for a year after that). That relay is intended to let either the BIRD or dash Boost Switch close the Big Boy relay. I had spent a fair bit of time trying to get and then reading documentation on how the system worked (including the BIRD, Big Boy, and Monaco supplied wiring diagrams), and I was confident that I had a pretty good understanding of how it worked. I was wrong.

It was acting up again recently, and I started doing some testing and was getting very strange voltage readings - sometimes the inputs to the Big Boy showed 8 to 9 volts, at other times around 3 volts. I pulled the Big Boy and had it bench tested by an electrical engineer working on a project with me, and it was drawing 10 amps when closed! Yikes! That is more than my solar panel puts out. I thought it was supposed to be a latching relay because the only documentation I could get from Intellitec's website said it was, but we took it apart and it has no latching mechanism. It turns out they sell two types that are both called Big Boy, they both look the same, and the only service documentation on Intellitec's website is for the latching version.

The documentation does say it needs 6 amps and 12 volts (10.5 v minimum) to activate, seems mine was a bit hungrier.

I tried Monaco and didn't get much from them, but I finally got in touch with Intellitec's RV support group. It turns out it is an RV electronics company in Ohio City, Ohio. I spoke to Chris who was very helpful and he explained that a bench test will show a high draw, but that the way it really works is that when the BIRD unit decides to close the relay it sends 6 amps and 12v to the Big Boy, and then after a fraction of a second it begins modulating the voltage so that if you read it with a meter you will see around 4 v (on mine I see 3) and you can hear it humming (which mine certainly does). At this point it is sending less than one amp to the Big Boy, but it is enough to keep the relay closed.

He confirmed that you CAN'T use the latching version as a replacement because of the way the BIRD unit activates the non-latching Big Boy. The other thing he confirmed is that when you push the Boost Switch on the dash it sends 12v and 6 amps continuously to the Big Boy, and if you keep holding the switch down beyond 30 seconds you will burn out the Big Boy. The BIRD unit can keep the Big Boy closed for hours without damaging it because of the modulation of the current.

This goes a long way to explaining why I could never make sense of the readings I was seeing. I did have another issue that my Magnum inverter was confused but I have a buddy who is a service dealer for them and he helped me reset it and the whole thing was working fine today.

If you want to see what your system is doing you have to attach a meter with a feature that remembers the high voltage it has seen in order to catch the momentary 12v spike.

That pretty much matches what I found with my older Intellitec BIRD ... once picked, the solenoid was held with 4 - 6 vdc. My BIRD was causing me some grief with my older solar package so I added a switch to cripple the BIRD when the RV is in storage with no shore power available.

http://www.irv2.com/forums/f54/yet-a...-s-145873.html

[CHCam42]

Distaf thanks for sharing this information.
Clark

[distaff]

Originally Posted by bruceisla

That pretty much matches what I found with my older Intellitec BIRD ... once picked, the solenoid was held with 4 - 6 vdc. My BIRD was causing me some grief with my older solar package so I added a switch to cripple the BIRD when the RV is in storage with no shore power available.

http://www.irv2.com/forums/f54/yet-a...-s-145873.html

Bruce - that is interesting. I have a small (80 watt) panel that came from the factory with a Heliotrope system to manage it. It was only wired into my coach batteries, and I also learned quickly that I had to cut off the batteries when I stored it or they would be dead flat in a couple of days even with everything in the coach turned off. I added a second circuit (the Heliotrope had the capacity but Monaco had chosen not to wire it), so it now charges both 12v systems.

I still forget to cut off the batteries on occasion and get back to flat batteries.