Coach battery is powering house - how to fix?

[lezmark]

I have confirmed with a voltage meter that the coach battery is helping the house batteries power the interior. I know that should not happen and there must be a broken switch or solenoid. Can someone please help me with where to find this "switch" and the best way (economical) to repair. I am a pretty good do it myselfer. Thanks

[RJay]

My guess is it could either be the BIRD failure that controls the solenoids that connect the coach and chassis batteries, or a solenoid failed closed. One way to test is to close the emergency start switch and see if you can hear the solenoid close. If it's failed closed you won't hear anything.

[Good man]

lezmark,
A little history would help us sleuth the problem:
1. When did this begin? ...Have you had any work done on the coach (even if unrelated to the batteries) since things were "normal"?
2. Have you had any electrical gremlins or glitches... a nearby lightning strike or spike in your pedestal or any abnormal generator/transfer switch issues?
3. Can you confirm the proper functioning of your battery isolator if equipped?
My initial thought is a "clampped on" booster switch caused by a faulty solenoid. Try to determine if the booster circuit is functioning properly.
Meanwhile, when parked you can probably use the chassis (starting) battery cut-off switch to keep it from being siphoned off by the house batteries.
Happy hunting and keep us posted...
Jim

[lezmark]

Originally Posted by RJay

My guess is it could either be the BIRD failure that controls the solenoids that connect the coach and chassis batteries, or a solenoid failed closed. One way to test is to close the emergency start switch and see if you can hear the solenoid close. If it's failed closed you won't hear anything.

If that is the battery boost panel button, I tried that and all was quiet...

[Good man]

I think you have found the source of the problem as RJay and I both suspected. That Boost solenoid is typically located in the house battery bay and will tie the house batteries over to the starting battery when the momentary contact dash switch is activated.
You can easily confirm if it is clamped on by testing. If you disconnect it, be sure to protect the energized lead cables from shorting against the frame.

[lezmark]

Originally Posted by Good man

lezmark,
A little history would help us sleuth the problem:
1. When did this begin? ...Have you had any work done on the coach (even if unrelated to the batteries) since things were "normal"? NO
2. Have you had any electrical gremlins or glitches... a nearby lightning strike or spike in your pedestal or any abnormal generator/transfer switch issues? NO
3. Can you confirm the proper functioning of your battery isolator if equipped? I dont know what that is. I discovered this by accident. I have been keeping my batteries charged while in storage by disconnecting the grounds to the house batteries. I was putting in a disconnect switch and when I still had power is how I discovered this. It could have been happening quite a while.
My initial thought is a "clampped on" booster switch caused by a faulty solenoid. Try to determine if the booster circuit is functioning properly.
Meanwhile, when parked you can probably use the chassis (starting) battery cut-off switch to keep it from being siphoned off by the house batteries. I dont think I have a cut off switch - I do have the use and store switch on my control panel. The only other battery related switch is on the dash - the boost... thanks for the help!
Happy hunting and keep us posted...
Jim

Thanks

[Good man]

lezmark,
We're getting our posts out of sequence here due to the response lag, but...
To answer your question;
A battery isolator is used in dual battery vehicles to ensure that each battery (or bank of batteries) gets a proper charge. The islolator senses battery status and switches between batteries so that when one battery is charged it does not allow the alternator to think it's work is all done.
Meanwhile, having determined that you are not hearing a click when the dashboard Boost switch is activated, I think you have found the problem.
If not, come back and we'll keep digging.
Jim

[lezmark]

Originally Posted by Good man

lezmark,
We're getting our posts out of sequence here due to the response lag, but...
To answer your question;
A battery isolator is used in dual battery vehicles to ensure that each battery (or bank of batteries) gets a proper charge. The islolator senses battery status and switches between batteries so that when one battery is charged it does not allow the alternator to think it's work is all done.
Meanwhile, having determined that you are not hearing a click when the dashboard Boost switch is activated, I think you have found the problem.
If not, come back and we'll keep digging.
Jim

I REALLY appreciate all the help. Can you tell me how to find/identify this isolator? I just looked around the battery and am not sure what I am looking for. There is one little box with a connection each side and I think it might be a fuse since I think I saw BUSS...

[RJay]

The isolator is usually in the power bay where your power cord is located. It's usually behind a piece of vinyl sheet on the back wall of the compartment but it could be somewhere else on your model.

[Good man]

lezmark,
I will be glad to help you with the isolator question, but may I suggest that you rule out the Boost solenoid before you go any further? All your symptoms seem to point at that little sucker as the culprit. Not good to go in two directions at one time when trying to ferret out a glitch like this.
You can Google "battery isolator" and any number of sites will pop up with pictures of the isolator and descriptions. Typically, it is located in the engine bay and is wired to the alternator... has big cooling fins on it.
I am not sure what the little box in your battery bay is, but it sounds like a fusible link... essentially a one-time circuit breaker... but it could also be a component of your "use/store" circuitry.
Keep working on locating that Boost solenoid... you won't be sure till you can get a distinctive click of a solenoid when you activate the dash switch... methinks it is the culprit.
Jim

[RJay]

Here is some information about RV battery isolation relays.

[Luv2go]

lezmark:

Your battery isolation relay should be located in a clear box on the firewall above your radiator. Along with the relay is a BIRD, which will connect the two batteries when either the engine is on or the coach batteries are being charged by the converter (i.e. when you have the coach plugged in or generator running).

If either the relay is frozen or the BIRD has failed you'll have both your batteries connected all the time as you have stated. Here is the service manual on a BIRD similar to what should be in your coach. It has a good troubleshooting section.

Note the Canyon Star replaced the Scottsdale in the Newmar lineup and it uses the 00-00362-000 BIRD. I had the opposite problem with my coach (the batteries were not being connected when the engine was running), that is why I know so much about it. I ended up replacing the relay with a larger 200A version.

This relay is the same one your Battery Boost switch connects to, there is no separate Battery Boost relay.

In the box you should find two relays, a larger Intellitec and a smaller one (usually White-Rodgers brand) with a wire going to the BIRD. That is the battery isolation relay. The larger Intellitec relay is the so called "Salesman switch" relay that turns off all power to the coach when you press "Store" on the control panel you also mentioned in an previous post.

I hope this helps!

[lezmark]

I think I have to cry uncle on this one. I have found it just where Luv2go (thanks for all the help by the way!) said it would be. It is VERY hard to get in to this box to work even if you remove the air cleaner box which it is behind. I know my limitations and with all those hard to reach wires (I can bearly find the screws that hold the BIRD in place let alone get in their with a tester!) and I think I just need to pay someone experienced to do this. Ouch. But its just not worth me taking a chance on.

Thanks again to all for your time and help!!!!!!!

[RJay]

Mark,
I apologize for misleading you on where to find the isolator, since you have a Newmar I was thinking it would be in the same place as mine but I now realize yours is not a diesel.