Go Back   Thor Forums > Thor Motorcoach & Motorhome > Class A Motor Coach
Click Here to Login
Reply
 
Thread Tools Display Modes
 
Old 07-12-2020, 03:11 PM   #1
Junior Member
 
Brand: Thor Motor Coach
State: Virginia
Posts: 8
THOR #5529
alternator not charging house batteries

2015 Thor Four Winds 33SW Super C. On my most recent trip I noticed that the house batteries we not being charged by the alternator while driving down the road. This has always worked in the past. I went to troubleshoot it when I got home and it was working! After several attempts I caught it when it was not working and found there was no voltage at the isolation relay on the terminal that actuates the relay (12v signal comes from the isolation delay relay). Intermittent IDR, right? I replaced it and no change - it still works sometimes and not other times. The IDR is getting the 13.5 - 14.0 volts from the alternator at all times so it's not a wiring problem. I find it hard to believe I got a bad IDR but that's all I can think of at this point. Any ideas out there?
__________________

__________________
Garyj is offline   Reply With Quote
Old 07-12-2020, 03:46 PM   #2
Senior Member
 
Oneilkeys's Avatar
 
Brand: Still Looking
Model: Travato
State: Florida
Posts: 2,389
THOR #1765
Youíre right, it doesnít seem likely that you would have two bad iDRs but the only possibilities that I see is another bad IDR or a problem in the wiring - either a connector or bad wire which intermittently makes a connection. I would try jumping the wire first.
__________________

__________________
Oneilkeys is offline   Reply With Quote
Old 07-12-2020, 04:00 PM   #3
Junior Member
 
Brand: Thor Motor Coach
State: Virginia
Posts: 8
THOR #5529
Thanks. I tried that and the wiring seems to be ok. I get alternator output voltage on the wire right at the input to the IDR whenever the engine is running. Sometimes the IDR supplies 12v to the isolator relay and sometimes not. The next thing I'll check more carefully is the actual alternator voltage at the IDR. The IDR spec says it activates after it sees 13.3v for 12 sec. Maybe I have some drop in alternator voltage from the engine compartment to the house.
__________________
Garyj is offline   Reply With Quote
Old 07-12-2020, 05:31 PM   #4
Junior Member
 
Brand: Thor Motor Coach
State: Virginia
Posts: 8
THOR #5529
OK. I looked more carefully at the alternator voltage "signal" to the IDR. When I disconnect the IDR at the connector the voltage at the connector reads 14.2v, same as the alternator voltage. When I plug it back in to the connector the voltage drops to about 13.6v. That's technically enough to activate the IDR (13.3) but there's not much margin and that could be why my problem is intermittent. There's no way that little IDR can be drawing enough to drop the voltage by .5v unless there's some resistance somewhere in the line. Looks like I will have to run a new wire from the engine compartment. Anyone know where this wire would plug into the chassis electrical system? it doesn't show battery voltage when the engine is off so it must be a switched source.
__________________
Garyj is offline   Reply With Quote
Old 07-12-2020, 05:35 PM   #5
Senior Member
 
Oneilkeys's Avatar
 
Brand: Still Looking
Model: Travato
State: Florida
Posts: 2,389
THOR #1765
Even if you had a temporary voltage drop from the alternator, It should kick right in again if the alternator gets back up above 13.3v. IDR sure seems like the culprit. Intermittent issues are the absolute worst to solve. Good luck.
__________________
Oneilkeys is offline   Reply With Quote
Old 07-12-2020, 05:39 PM   #6
I Think We're Lost!
 
Bob Denman's Avatar
 
Brand: Still Looking
Model: Tiffin Wayfarer 24 BW
State: New York
Posts: 16,124
THOR #8860
The IDR...
https://www.thorforums.com/forums/at...1&d=1594575547
Attached Thumbnails
Click image for larger version

Name:	What He Said....jpg
Views:	23
Size:	17.1 KB
ID:	24796  
__________________

__________________
Good Sam Member 843599689
Current coach: Tiffin Wayfarer 24 BW
"History shows again and again; how Nature points out the folly of Man!"
Bob Denman is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Thor Industries or any of its affiliates. This is an independent, unofficial site.




All times are GMT. The time now is 08:48 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0 PL2
×