need help battery isolator

[rvgara]

Hi all. Recently realized that my 2005 Lexington house batteries (2 deep cycle) are electrically connected to my chassis battery. When the chassis battery is disconnected and shore power unplugged, the engine starts up so I know it is starting from the 2 parallel house batteries. When I plug in to shore power the converter is putting out 13.6 volts to all 3 batteries. So if I understand correctly, I have a battery isolator problem. I enclosed a picture of what I think is my isolator but not sure. These 2 solenoids in my battery bay look to me like the old ford starter solenoids but with an extra small wire attachment. I labeled the terminals in the picture, and any help with diagnosis would be greatly appreciated. The large terminals A,B,C and D are hot at all times, even if I disconnect the chassis battery. The small wires 1,2,3 and 4--of these terminal 3 on lower solenoid is hot but none of the others. The upper solenoid has a label "Ignition Proof Coach Chassis" and I don't know what that means. I am handy with a test light, voltmeter and ammeter. I did auto repair for 34 years before retirement, but this is a new system for me. I don't know how it is supposed to work and I have no wiring diagram. I checked the "boost" switch on my dashboard which is supposed to connect the house and chassis batteries in case of low house battery, and that switch is OK. Disconnecting it completely changes nothing. Thanks in advance and sorry for long post.

[Bama Rambler]

That looks like a B.I.R.D (Bi-directional Isolator Relay Delay), but there should be a third relay.

Here's one manual for a B.I.R.D. It should be similar to yours.

[bubbles]

Just one input. The boost switch is to tie the coach and chassis batteries together in case of low CHASSIS battery. Provides coach batteries for starting. The converter will charge all batteries with shore power and I believe the engine alternator will charge all batteries with engine running. If you look at the positive cable on your chassis battery I think there will be 2 battery cables and I think one of those is from the coach batteries so even though the chassis battery is disconnected there will still be 12 volts on the chassis battery cable. Of course I may be way off base here. What I have presented here is for my GT 378 and may be a moot input (except for boost switch function) for your configuration.

[rvgara]

Thanks for the replies. So is the BIRD that little electrical panel just to the left of my 2 solenoids? And I did mis-speak about the boost switch. Absolutely it is to boost the chassis battery and not the house batteries. I have only a single wire coming off of my POS battery terminal at the chassis battery. Does anyone have a source for wiring diagrams? I have access to a diagram for the 2005 E450 van, but not for the RV side of the electrical system. I was told by WFCO who makes my converter that it is designed to charge ONLY my house batteries and not my chassis battery. They went on to say that charging 2 different types of battery at the same time could potentially eventually damage the WF8955 converter. Of course the 2 different types of battery are the dual deep cycle house batteries and the underhood regular chassis battery. That is why I need to figure this out-to protect my converter. The engine alternator is charging all 3 batteries at 14.4 volts with the engine running. I assume that once the engine starts and the alternator kicks in, that the isolator or BIRD electrically kicks off the converter output and allows the alternator to do it's thing and keep all 3 batteries charged.

[bubbles]

OK. Your picture appears to be the battery disconnect (top one) solenoid and the bottom one looks like the interconnect solenoid for chassis and coach batteries. Someone with a Lexington should chime in. I think the rep from WFCO is misinformed.

[Trksr]

Your test dos not necessary prove the bird controller is bad. If your coach batteries were at 13 volts the controller would operate the isolation relay even with the chassis battery being disconnected.

You must run the coach batteries down to 12.7 or less . Then perform the test again.

[bubbles]

Originally Posted by Trksr

Your test dos not necessary prove the bird controller is bad. If your coach batteries were at 13 volts the controller would operate the isolation relay even with the chassis battery being disconnected.

You must run the coach batteries down to 12.7 or less . Then perform the test again.

I'm in this corner concerning the isolation/interconnect relay. Good point.

[HerveVR]

Have a look at the Lexington Forum on this site; might find help.

[rvgara]

Originally Posted by Trksr

Your test dos not necessary prove the bird controller is bad. If your coach batteries were at 13 volts the controller would operate the isolation relay even with the chassis battery being disconnected.

You must run the coach batteries down to 12.7 or less . Then perform the test again.

Hi all. Well my batteries were at 12.6 volts when the engine started off of just the house batteries. Shore power was unplugged and chassis battery was disconnected and the 2 house batteries were putting out 12.6 volts. But if WFCO rep is wrong and the converter IS supposed to be charging all 3 batteries at the same time then maybe I have no problem? I just noticed that my switch for "use/store" mode no longer works. The light on the switch shows "use" mode is active at all times. Switch seems to be working because I hear a click from somewhere when I push the rocker switch, but all 12 volt coach items continue to work even when I try to put it in "store" mode. This further leads me to believe that my chassis battery is still connected to the coach and powering up the coach. And I will check out the Lexington forum also. Thanks.

[bubbles]

Originally Posted by rvgara

Hi all. Well my batteries were at 12.6 volts when the engine started off of just the house batteries. Shore power was unplugged and chassis battery was disconnected and the 2 house batteries were putting out 12.6 volts. But if WFCO rep is wrong and the converter IS supposed to be charging all 3 batteries at the same time then maybe I have no problem? I just noticed that my switch for "use/store" mode no longer works. The light on the switch shows "use" mode is active at all times. Switch seems to be working because I hear a click from somewhere when I push the rocker switch, but all 12 volt coach items continue to work even when I try to put it in "store" mode. This further leads me to believe that my chassis battery is still connected to the coach and powering up the coach. And I will check out the Lexington forum also. Thanks.

In your picture terminal #3 I believe is on the isolation/interconnect relay and being there is 12volts at #3 the relay is energized tying the batteries together.

[bubbles]

That relay would be controlled by a B.I.R.D if you have one.

Additionally; In my unit the battery disconnect light at the battery disconnect switch will be illuminated continuously even with the coach batteries disconnected with the engine running (isolation/interconnect relay energized). I believe this may be what you have concerning your "USE" light.

[bubbles]

In my unit the only B.I.R.D bypass for the isolation/interconnect relay is from the AUX/Emergency start switch. That switch applies a direct 12 volts to the relay to energize it. Wish I knew more about your unit.

[dontay]

The hardware in the picture is not the BIRD. The BIRD is usually located under the driver's seat but not always. Mine turned out to be under the floor behind the driver's seat.
Terminal 3 is the hot side of the relay coil. That relay connects the coach and chassis batteries together for charging. Terminal 3 is driven to 12V by either the BIRD or the Emergency Start switch. Since you state that it remains 12V even if the emergency start switch is disconnected it could only be driven to 12V by the BIRD. Unless it is miswired. With shore power off I suggest you locate the BIRD and disconnect the Coach Battery input wire. If Terminal 3 does not drop to zero then it is miswired. If it does drop to zero but goes back to 12V when you reconnect the coach battery wire than the BIRD is faulty.
The wiring diagram provided in another post is very clearly written and explains how the system works. Also, my BIRD looked just like the one shown in the drawing.
Before you start this touch the backside of a finger to the solenoid. If it is on all the time it will be quite hot. If it is cool your batteries may be wired together and that is very bad.

[rvgara]

Thanks so much for the detailed diagnostic info! I have my work cut out for me but now it will be easier with this info.