Community Forums

moisheh · 09-16-2019, 11:55 AM

Monaco used a lot of different methods to keep the batteries charged. Our 08 Dynasty has 8-6 volt batteries. House Fridge.In the rear run bay there is a Big Boy solenoid and 2 or 4 smaller solenoids. The controller is in that rear run bay. I cannot remember who made the board. It is either by Intellitec or the Oregon based company that produced a lot of boards for Monaco. When on shore power the house batteries are charged by my Magnum charger/inverter. I have replaced the Big Boy about 3 years ago and at that time I installed a new board/controller. Today I installed new 6 volts and last week new chassis batteries. For about 2 years I have had a problem charging the house batteries from the alternator. I would start off in the morning by running the genset for awhile. But once I was driving the house batteries were not charging. I can read this on my Alladin. It would show the house batteries as discharging by a few amps. After maybe a half hour they would start charging at up to 30 amps. Sometimes this would happen in 15 minutes. I haven't opened up that rear run bay yet. I know it has a red light to tell you something is wrong and I think a fuse. Any suggestions appreciated.

vito.a · 09-16-2019, 12:17 PM

We have some Monaco electrical system experts on here. I'm not one of them, but I've had battery charging issues and every time they were caused by the large Intellitec Big Boy solenoid.
The system is set up so that when the engine is running it charges the chassis battery first, then when the preset voltage is reached the Big Boy should close and charge the house batteries. It works in reverse when plugged into shore power (or generator) and charges the house batteries first and when the preset voltage is reached, it charges the chassis batteries. This is assuming you have the inverter charging turned on.

It is possible to disassemble the Big Boy solenoid and clean the copper contacts. They come from Intellitec with a grease like substance on the contacts and it tends to burn and create carbon.
Attached below are the Big Boy relay cleaning instructions courtesy of Mike Canter. Just be careful as there are a lot of amps available from the battery packs.

moisheh · 09-16-2019, 03:26 PM

Vito: Thanks. I think you have hit the nail on the head. I will have to wait until we head south next month . I will see if the solenoid will switch to charging the house batteries. I have a complete Big Boy that needs to be cleaned up. I remember reading that the contact is a common Delco HD truck starter part. Where we are in Mexico there are some really good auto electrical shops. They will have that contact. Thanks again.

pduggs · 09-16-2019, 03:47 PM

Please let us know what results.

I haven’t experienced that issue on my coach, but I have four house batteries not eight. Though I have a residential frig.

moisheh · 09-16-2019, 03:49 PM

Paul. The 8 batteries were standard on Dynasty's with a residential fridge. Great idea but hurts when you need new ones! I will probably do the repair sometime this winter.

twinboat · 09-16-2019, 03:57 PM

Just a point of info.

The big boy solenoid doesn't switch the charging from one battery to the other. It combines the banks together when conditions are met.

pduggs · 09-16-2019, 04:30 PM

Quote:

Originally Posted by moisheh

Paul. The 8 batteries were standard on Dynasty's with a residential fridge. Great idea but hurts when you need new ones! I will probably do the repair sometime this winter.

Yes. My coach didn’t come from the factory with the RF. Prior owner added it a year before I bought, but didn’t upgrade the battery bank.

I want to add four more house batteries to the upper slide tray and move the engine batteries to the small far rear compartment. If you could, could you please take some pictures of your battery compartments and send to me? I am unsure how to run the cables or where to move the two shut off switches.

Persistent · 09-16-2019, 04:44 PM

"For about 2 years I have had a problem charging the house batteries from the alternator. I would start off in the morning by running the genset for awhile. But once I was driving the house batteries were not charging. I can read this on my Alladin. It would show the house batteries as discharging by a few amps. After maybe a half hour they would start charging at up to 30 amps. Sometimes this would happen in 15 minutes. "

Isn't this the way it is supposed to work? 15 minutes to 1/2 hour is about right to charge the chassis batteries before adding in the house batteries.

rpasetto · 09-17-2019, 06:50 AM

The setup on my '03 Dynasty is a bit different, I think.
- Alternator feeds, to a big isolator inside the Pass. Side rear 'run box' (isolator is essentially big high current diodes inside a heat sink).
- From the isolator, wires split to the chassis and house circuitry (there's a disconnect switch on each before the battery banks).
- Also inside the PS rear 'run box' is a large relay which is wired to connect the chassis and house circuitry together' it's triggered by a momentary switch on dash labelled something like "emergency start".

I do not know if this is similar to later years.

RobRoy · 09-17-2019, 07:23 AM

Quote:

Originally Posted by vito.a

We have some Monaco electrical system experts on here. I'm not one of them, but I've had battery charging issues and every time they were caused by the large Intellitec Big Boy solenoid.
The system is set up so that when the engine is running it charges the chassis battery first, then when the preset voltage is reached the Big Boy should close and charge the house batteries. It works in reverse when plugged into shore power (or generator) and charges the house batteries first and when the preset voltage is reached, it charges the chassis batteries. This is assuming you have the inverter charging turned on.

It is possible to disassemble the Big Boy solenoid and clean the copper contacts. They come from Intellitec with a grease like substance on the contacts and it tends to burn and create carbon.
Attached below are the Big Boy relay cleaning instructions courtesy of Mike Canter. Just be careful as there are a lot of amps available from the battery packs.

X2 and how "my" system works.

The first time I rebuilt the Big Boy relay in my shop and worked fine for about 2 years

The second time I replaced the Big Boy relay itself and has been fine since.

and I would catch the failure the same way the OP did and by paying attention to my Aladdin and notice a less than charging system rate and then see them start to discharge.

Happy Trails

twinboat · 09-17-2019, 07:48 AM

The large diode based system went out of favor right around the time your MH was built.

The solenoid type system elemenates the voltage drop thru diodes and can be configured for bi-directional charging.

Isolators block feedback to the alternator regulator, so a battery sense wire was needed. If that was lost, the alternator could overcharge. That didn't sense house battery voltage and they were sometimes left undercharged.

You probable also have another device near the isolator that looks the same and charges the chassis battery while on shore power.

shootist · 09-18-2019, 05:39 PM

Just cleaned my big boy. Flipped the disc and turned the studs so all new contact surfaces. A while back I installed a toggle switch to shut it off while plugged in. The solar keeps the chassis batteries up just fine. Couldn't stand that humming in the bedroom.

rpasetto · 09-19-2019, 10:51 AM

Quote:

Originally Posted by twinboat

The large diode based system went out of favor right around the time your MH was built.

The solenoid type system elemenates the voltage drop thru diodes and can be configured for bi-directional charging.

Isolators block feedback to the alternator regulator, so a battery sense wire was needed. If that was lost, the alternator could overcharge. That didn't sense house battery voltage and they were sometimes left undercharged.

You probable also have another device near the isolator that looks the same and charges the chassis battery while on shore power.

Interesting, going away from solid state and back to mechanical relays. I'll put changing it out on my to-do list. Of course with the Big-boy contact resistance can become an issue when contacts need to be cleaned... about how often does that need to be done?

By the way, I swapped out the old Lambert battery-maintainer for a Xantrex Echo-Charge about a decade ago.