Community Forums

wogden · 09-15-2013, 05:45 PM

My friend has just purchased a used 2000 Thor Chateau Sport 28' with the Ford V10. It has 31000 miles on it and seemed to be in great shape. First trip out and the batteries went dead after 2 days. They will recharge when connected to shore power but not from driving around. Has no issue with the primary engine battery so we know that the alternator is functional. Can someone give me some hints as to where to look first to resolve this issue.

trackman · 09-15-2013, 05:57 PM

Hard to accept but the house batteries cannot be charged by the chassis battery alone. You will have to run the generator some while traveling if you are running fridge and or other things during your travel

bearaboo · 09-15-2013, 06:03 PM

It sounds like the battery isolator/ solenoid. It connects the chassis and house battery while driving to charge both batteries. When you turn off the engine it disconnects the two batteries. You will probably find it on the drivers side underneath the brake fluid reservoir. It looks like a starter solenoid, but it is designed for continous duty. When you start the engine, you should hear a click after a few seconds indicating that the solenoid is working, connecting the batteries. If you have an emergency start switch, that also engages the solenoid to connect the house battery with the engine battery if it is low and won't start the engine. It is easy to replace. Just make sure you get a continous duty solenoid. Here is a link for some more information.

http://www.neon-john.net/RV/Electric...ion_relays.htm

Old Bounder · 09-15-2013, 06:06 PM

The engine alternator should have sufficient capacity to run the engine, keep the chassis battery charged AND also charge th ehouse batteries. It may take longer than you expected, depending on how depleted they are and how long you drive.

You indicated that they would not charge at all from the alternator. This indicates a problem with the battery isolator solenoid and/or associated circuitry.

John Pacello · 09-15-2013, 06:16 PM

Search this thread, it helped me...

Coach batteries will not charge while the driving.

John

FIRE UP · 09-16-2013, 10:42 AM

wogden,
As has been stated, the alternator on todays coaches is more than enough to keep all the operations of the engine etc. running and, still charge both the chassis batteries and house batteries. Some are more powerful and have higher amp output than others. You would be good to advise your friend to learn what kind and model of alternator he has and, what the output is on it. That way he'll know just what its capacity for various situations.

Now, as far as your house batteries not being charged while the engine is running. Yes, your alternator SHOULD be charging them adequately. But, if it's not charging them, then obviously a break down in that portion of the system has happened. In the old days, and has been stated, the older style of what was/is called a "Battery Isolator" looked just like a Ford starter solenoid. The main difference between those and the Battery Isolator is the fact that the battery isolator is a continuous duty unit. There used to be a "trigger wire" that engaged that solenoid so that the charge from the alternator which, was sent to that solenoid, was split between the two sets of batteries.

The trigger wire was only hot when the ignition was on and, usually after a timed sequence. They didn't want it (the solenoid) energized while the engine was cranking.

But todays battery isolators have changed looks and operational characteristics. I've replaced some that didn't even appear to be a solenoid until I removed a glued on cover that revealed it's inner workings. and, what I found was much more complicated than the old Ford solenoid. So, what this all means is, you and or your buddy, will have trace the output of the alternator to the point where you find whatever kind of isolator is used on that particular motor home.

Then, once that's found, some tests will need to be performed to see if the alternator output is stopped there, or it continues on which, means the breakdown for charging is beyond the solenoid. So, hope this helps some.
Scott

GaryKD · 09-16-2013, 10:44 AM

Hi wogden,
Consider calling the manufacturer's customer service number and ask them if the coach was designed to charge the coach (house) batteries from the alternator. While there are iRV2 members who preach every coach charges the house batteries from the alternator, I have personally been involved in situations where that is not the case.

This is very coach specific. Consider asking the moderators to move this thread to the Thor Owners Forum on iRV2. Nobody knows your coach like somebody who owns one just like yours. In addition to the manufacturer, that is where your information should come from.

OldJohnT · 09-16-2013, 05:01 PM

Ive seen that happen on 2 different coaches. The isolation solenoid fails to engage even when you hear it click due to non use and rust and corrosion etc. On mine theres an extra big battery cable on the engine battery that attaches to the solenoid and then another big cable back to the house batteries. Its a 12 VDC but 100 duty versus look alike solenoids for short term starting only. Some use a solid state isolator instead of a solenoid and they can go bad also

John T

ga traveler · 09-16-2013, 06:23 PM

Quote:

Originally Posted by trackman

Hard to accept but the house batteries cannot be charged by the chassis battery alone. You will have to run the generator some while traveling if you are running fridge and or other things during your travel

I have never seen a motorhome that came from the factory without a charge circuit that was designed to charge both sets of batteries when the engine was running. I have repaired dozens that had a bad solenoid and caused the system to fail.

tompen · 09-16-2013, 06:52 PM

wogden
The coach most likely has a Battery Control Center (BCC, or BIRD). My 2001 Thor Manufactured Damon has one. The most common problem is with the isolator relay already mentioned. There are several steps to take for diagnosis. Only a few steps can be explained at a time because the next steps depend on the results of the previous ones. Do you want us to try to go through this with you or is your friend on the forum. This could take a while.
Tom

wogden · 09-17-2013, 03:48 AM

Many thanks for all the replies. I have passed on the info to my friend and he will be speaking with a local mechanic regarding this issue. At this time no further steps need to be taken as I am leaving for the west coast on Thursday and Carl is not on the forum yet. I will stay in touch with him and update this as he progresses. Thanks again for all the help. Walt