House batteries not charging while driving

[Viperman27]

My 2006 Monaco Diplomat diesel pusher is not charging the house batteries while driving. The solenoid operates off of the battery booster switch. We have verified there is voltage on the purple wire while pushing the battery booster switch. Thinking maybe it's the isolator relay delay board but need direct replacement. Any suggestions?

[twinboat]

With power on the purple wire, see if there is equal voltage on both large terminals. Test each one to ground. If they read each batterys voltage it's failed.

Often times the solenoid powers up but due to pitting and burnt contacts it doesn't connect internally to tie the batteries together.

[l1v3fr33ord1]

Viperman27-

First off, welcome to iRV2!

Second, you should add a "signature" to your profile. It contains whatever info you want; most people put info about their coach there, so they don't have to type it into each message. Instructions for adding a signature are here.

Re: The Isolator Relay Delay board. Here is a post on a similar thread that includes information for a BIRD (Bi-directional Isolator Relay Delay) board. It is a drop-in upgrade to the IRD board.

Per "Twinboat," testing is recommended to ensure the IRD has failed; the solenoid is the more common failure item in that circuit.

I have wiring diagrams for your coach. If you send me a private message that includes your e-mail address, I'll send the diagrams to you. Don't "publish" your e-mail address in public here, or the spammers will get it. Instructions on sending a private message are here.

[windsorbill]

Viperman27

You say you have an "isolator Relay Delay', commonly called a IRD. Mine is in the front run bay. It has to see 13.2 volts for 12 seconds from the alternator BEFORE it will send a signal to the solenoid. It is fed through the ignition switch.

Before you change out the IRD, check the voltage coming in. I had a voltage drop from the alternator to the front run bay and could only get 12.9 volts coming into the IRD.

[twinboat]

He is getting power to the purple wire, it's not the IRD or BIRD.

[l1v3fr33ord1]

Originally Posted by Viperman27

We have verified there is voltage on the purple wire while pushing the battery booster switch.

Originally Posted by twinboat

He is getting power to the purple wire, it's not the IRD or BIRD.

In the Monaco design (of this era) the solenoid gets its 12V "activation" voltage from the BATT BOOST switch and the IRD/BIRD through parallel paths. So, it's possible the solenoid activates with the BATT BOOST switch and fails to activate via the IRD, either because the IRD has failed or because the conditions needed for the IRD to send the "activation" voltage have not been met, as per "windsorbill's" post.

[kenwyatt]

Sounds like a failure I had. Key was the Big Boy wasn’t pulling in when it should have to keep the house batteries and chassis batteries charged when plugged into shore power. It would pull in and lock until I turn on the ignition and started the engine. After I shut it down the BB wouldn’t pull in unless I pressed the Boost switch and it would pull in again and lock in until the process was repeated. What I found was my B.I.R.D. relay did not have the 12 volt signal on the terminal marked Batt because a cb feeding it the battery reference voltage was tripped. I probably tripped it while working on the battery bank and did not realize it. Reset the cb and has been working normal for over a year. No guarantee but check you’re reference voltage at the IRD or B.I.R.D. board.

[nehog]

There is, in the front electrical box under your feet, a small circuit that controls that relay. It has a couple of things, a delay and a voltage check before it will trip on the solenoid relay to charge both sets of batteries.

If you wish, I can shoot a picture of it, and post. There is also a relay right next to that circuit board too which could be the problem.