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Topic: battery charging

Posted By: Dave22 on 07/18/15 09:00pm

Coachmen freelander.
My engine does not charge the coach batteries. What do I look for?

Posted By: 1492 on 07/19/15 01:36am

Moved from Forum Technical Support

Posted By: wolfe10 on 07/19/15 06:33am

Trace the large-gauge wire from the alternator B+ terminal. It will go to a battery isolator.

It could be a DIODE-BASED isolator or SOLENOID-BASED isolator. You need to verify charging voltage to it from the alternator and charge voltage out to the coach (house) battery bank.

Brett Wolfe
Ex: 2003 Alpine 38'FDDS
Ex: 1997 Safari 35'
Ex: 1993 Foretravel U240

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Posted By: eric1514 on 07/19/15 06:53am

As the post above says find the isolator. If you have a starting boost switch up front, listen for the click when you press it. That's the solenoid you're looking for.

2015 Travato 59g

Posted By: Vulcan Rider on 07/19/15 08:27am

First look to be sure your battery disconnect switch is ON.

When mine did that it indeed was the "battery relay" solenoid and was a relatively inexpensive fix.....even at CW.

Posted By: Dave22 on 07/19/15 11:10am

Booster switch enabled locating the solenoid isolator. Pressing the booster sw retracted the step. With engine off, volt into isolator = 12.80, out of iso = 12.47. With engine running and charge voltage of 14.9, volt into iso = 14.9, out of iso = 12.79. I think there may be more than one problem. The battery disconnect is one of those momentary contact switches and the position of the switch did not effect the above readings. I still do not know the resolution to this problem and I hope this helps. Thanks to you all.

Posted By: tpi on 07/19/15 01:13pm

If you push the booster switch with engine on what happens to voltage out of isolator?

From what I'm reading so far it sounds like defective isolator (provided you are measuring out voltage right at isolator). But it also could be no trigger from ign to isolator.

Posted By: Dave22 on 07/19/15 03:50pm

Pushing the booster button with the engine on increases the voltage out of the isolator to 14.xx from 12.79. Voltages were measured at the isolator.

Posted By: Vulcan Rider on 07/19/15 04:08pm

Dave22 wrote:

Pushing the booster button with the engine on increases the voltage out of the isolator to 14.xx from 12.79. Voltages were measured at the isolator.

The relay/solenoid/isolator often exhibits a high resistance due to burnt contacts before it fails completely.

Your readings indicate that it's contacts aren't making a good connection.

If you search around on here a bit you might find other threads that talk about how to "fix" that solenoid......if you are into doing things like that. In my book, a new one is a better solution.

Posted By: tpi on 07/19/15 06:17pm

Dave22 wrote:

Pushing the booster button with the engine on increases the voltage out of the isolator to 14.xx from 12.79. Voltages were measured at the isolator.

Then that makes me think there is no voltage from the ignition to trigger the isolator relay. There should be some kind of lighter gauge wire from the ignition to the isolater that shows 12+ volts when the switch is turned on. It could be picking up that ignition signal from any fused ignition-on circuit. That wire would be well worth tracing back and see why power isn't present on it when ign is switched on. The booster button is essentially bypassing that trigger.

I'm going on assumption you have something like this:

* This post was edited 07/19/15 06:34pm by tpi *

Posted By: Dave22 on 07/20/15 12:32pm

One of the two 12VDC wires at the Battery control solenoid goes to the generator panel and the other goes in the direction of the converter. These two devices provide charging to the coach batteries. There does not seem to be anything heading toward the engine. I wonder if the engine charge feature was omitted for some reason although the owner's manual says it is included. Maybe a wire of a different color makes it to the engine from one of the other chargers. A wiring schematic would be helpful. Any further suggestions? I've sure learned a lot so far and thank you all.

Posted By: tpi on 07/20/15 01:18pm

How many wires are coming out of the solenoid in all? Just two?

Posted By: burlmart on 07/20/15 01:59pm

probably different from coachman, but these pics may help you guys figure some things together

this is the wiring a fellow r-vision owner put together for our RV

this is the electronic unit

this is a user manual,d.aWw

2005 Trail Lite 213 B-Plus w/ 6.0 Chevy

Posted By: Dave22 on 07/20/15 02:50pm

Yes, just two 12vdc wires from the solenoid. However, the emergency start button has to have a wire somewhere. I'll try to digest the pictures. Thanks.

Posted By: tenbear on 07/20/15 05:22pm

burlmart's pic shows 2 large terminals and 2 small terminals on the solenoid. Some solenoids have only one small terminal, the case being the -12v connection. When the 12v is applied to the solenoid the 2 large terminals should be connecter together internally. The voltage should be the same on both large terminals. If it's not, the solenoid is bad.

Class C, 2004/5 Four Winds Dutchman Express 28A, Chevy chassis
2010 Subaru Impreza Sedan
Camped in 45 states, 7 Provinces and 1 Territory

Posted By: Dave22 on 07/21/15 02:02pm

The emergency start/booster button operates the solenoid I have been referring to in this discussion. I have found nothing else that operates this solenoid, not the generator or the shore power via the converter and certainly not a running engine. This solenoid is not defective.
I noticed the picture from burlmart shows two solenoids. I don't know how all this is supposed to work but I feel I need to look for another solenoid. If any of you have more suggestions I'm sure they will help.Thanks

Posted By: burlmart on 07/21/15 03:23pm


if you give your year and model, some others may steer you to good specific info.

RVs for a dozen yrs or so use an Intellitec BIRD that is well described in the pdf i linked. it is what controls the isolator solenoid responsible for how both batteries get charged.

the lower solenoid in my pics is typical to all RVs. it's the house battery disconnect thing. it may not be right there with the isolator solenoid for you, as for my rig. it is what you switch on/off, or USE/STORE via a toggle switch near the coach entry steps

* This post was edited 07/21/15 03:58pm by burlmart *

Posted By: tenbear on 07/21/15 04:04pm

Could you post a picture of your solenoid? It might help us understand better.

Posted By: Dave22 on 07/21/15 04:40pm

I found the correct? solenoid under the oven behind a drawer. The latch-in feature from the momentary "Battery disconnect" switch must be a characteristic of the solenoid because I found no other controls in the area. It seems to operate from the generator and from shore power but not from a running engine, my original problem.
I looked at the procedure for posting a photo and it looks beyond me. I can email you a picture if you still think it helpful. Thanks.

Posted By: Dave22 on 07/21/15 08:07pm

My RV is a 2008 Coachmen Freelander. It doesn't use Intellitec but I found the info helpful in understanding. There are no "black boxes" associated with my system that I have found, just two solenoids (so far)and some wiring. Oh, the chassis is Workhorse. The two wires which go to my newly found solenoid are brown and white (and, also, the big wires from the batteries.)
I think I need to know where the solenoid gets its signal which indicates that the engine is running.

Posted By: Dave22 on 07/21/15 08:37pm

Is there a difference between "ignition on" and "engine running"?

Posted By: burlmart on 07/22/15 03:45am

Dave22 wrote:

Is there a difference between "ignition on" and "engine running"?

i think not.

if no BIRD, and a manual says your engine is supposed to charge both batteries, then maybe the isolator solenoid is bad. also, there may be a 'black boxish' diode that does what the BIRD does.

i disconnected my BIRD and the 2 small terminal wires that trigger the isolator solenoid to couple the 2 batts (they are the 2 big terminals).

those isolator solenoids go out like camera flash bulbs. after the second iso solenoid ruined both new batts by being stuck on always, i disengaged it. the other solenoid for house battery disconnect is fine.

if your iso solenoid is bad and there is no blown fuse to it, it may be hot to the touch as one indicator. mine was stuck on and warm, but in your case, since it seems to be off, if there is no fuse (mine had none), maybe the diode thingy is bad, or maybe the previousowner did what i did.

if you hear the iso solenoid click when toggling the emergency start switch on the dash, it is connected to the ignition. a multimeter touching both small iso terminals would read 12+ V when the solenoid is on.

Posted By: tenbear on 07/22/15 05:11am

Now that you have found the correct solenoid, with the control wires as well as the battery wires, a photo is probably not necessary.

Posted By: Dave22 on 07/23/15 11:04am

There was a blown 5 amp fuse in a separate fuse holder under the driver's seat. Fixed it. Thanks to everyone who tried, it was a great learning experience.

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