Community Forums

broadrun · 03-13-2014, 06:58 PM

All,

I'm not sure if this solenoid is working anymore. Any ideas on how to test it? I see it is rated at 21 Ohms so is it as simple as hooking up a meter?

Gorlininc · 03-13-2014, 07:20 PM

I changed mine when my batteries charged slowly. It's $63 and mine was 10. Years old so I just changed it.

broadrun · 03-13-2014, 07:32 PM

Quote:

Originally Posted by Gorlininc

I changed mine when my batteries charged slowly. It's $63 and mine was 10. Years old so I just changed it.

Thanks. Which one did you buy? I see a Trombetta that folks keep taking about...

Mike Canter · 03-13-2014, 08:40 PM

Buy the Trombretta it is better made. The 21 ohms is through the electromagnetic coil section which energizes the solenoid. The other part is the contacts within the solenoid which joins or disconnects the two large terminals ontop. Most of the time those get pitted from arcing and sparking and that is most likely what has happened to yours.

broadrun · 03-13-2014, 08:42 PM

Quote:

Originally Posted by Mike Canter

Buy the Trombretta it is better made. The 21 ohms is through the electromagnetic coil section which energizes the solenoid. The other part is the contacts within the solenoid which joins or disconnects the two large terminals ontop. Most of the time those get pitted from arcing and sparking and that is most likely what has happened to yours.

Thanks Mike. Will do.

tricotec · 03-14-2014, 03:16 AM

A ex-Monaco tech at Elite Repair & Remodel tested mine with a voltmeter. When the solenoid is off, the voltage is different on the two large terminals. If the solenoid is on, the voltage should be exactly the same. If it isn't, the solenoid is toast. Mine was bad and needed replacement.

promine · 03-14-2014, 11:19 AM

Quote:

Originally Posted by Gorlininc

I changed mine when my batteries charged slowly. It's $63 and mine was 10. Years old so I just changed it.

Is that an indication that the fat boy is going bad, when the batteries take longer to charge? I have noticed that once and a while I need to run the Onan for a while going down the road till the batteries get back up to 13 V so the inverter will work.

Gorlininc · 03-14-2014, 11:32 AM

The inverter charged your house batteries. The big boy solenoid closes and charges the chassis batteries. So if you are on shore power and your chassis batteries don't fully charge fairly quickly I'd change the big boy. I replaced it with the Trombretta solenoid. Make sure you get 200 amp with silver contacts.

Denali · 03-14-2014, 11:47 AM

Can't you test by simply hitting the Battery Boost switch (or whatever your coach has to tie the house and coach batteries together) and watch the voltage on one set of batteries go up?

broadrun · 03-14-2014, 12:21 PM

Quote:

Originally Posted by Gorlininc

The inverter charged your house batteries. The big boy solenoid closes and charges the chassis batteries. So if you are on shore power and your chassis batteries don't fully charge fairly quickly I'd change the big boy. I replaced it with the Trombretta solenoid. Make sure you get 200 amp with silver contacts.

I didn't think that the chassis batteries are supposed to be barged when the coach is on shore power. That is why I purchased the Xantrex Echo Charger, or at least I thought. Isn't the fat boy solenoid used simply to tie the coach and chassis batteries together for emergencies when you may need to jump from one to another using the rocker switch???

broadrun · 03-14-2014, 12:22 PM

Sorry, charged, not barged.

Gorlininc · 03-14-2014, 12:32 PM

The echo charger charges the chassis batteries while on shore power from the house batteries and inverter. That means you have an IRD system.
When you are driving your alternator charges your chassis batteries. When the voltage on your chassis batteries reaches 13.5 volts the IRD closes the big boy relay and keeps it closed and charges your house batteries while traveling also.
The big boy also activates when you push the aux power switch.

Denali · 03-14-2014, 01:56 PM

Quote:

Originally Posted by broadrun

I didn't think that the chassis batteries are supposed to be barged when the coach is on shore power. That is why I purchased the Xantrex Echo Charger, or at least I thought. Isn't the fat boy solenoid used simply to tie the coach and chassis batteries together for emergencies when you may need to jump from one to another using the rocker switch???

Our coach has a BIRD-2 relay that controls the Big Boy. From the BIRD-2 manual:

"The BIRD (BIDIRECTIONAL ISOLATOR RELAY DELAY) performs two important functions. It provides a method of charging the coach battery from the engine alternator and charges the chassis battery from the converter when the coach is plugged into shore power."

In other words, both sets of batteries get charged from both sources.

bruceisla · 03-14-2014, 02:10 PM

Quote:

Originally Posted by Denali

Our coach has a BIRD-2 relay that controls the Big Boy. From the BIRD-2 manual:

"The BIRD (BIDIRECTIONAL ISOLATOR RELAY DELAY) performs two important functions. It provides a method of charging the coach battery from the engine alternator and charges the chassis battery from the converter when the coach is plugged into shore power."

In other words, both sets of batteries get charged from both sources.

when everything is working correctly ....