Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
 

Go Back   Thor Forums > Thor Tech Forums > Maintenance and Repair
Click Here to Login
Reply
 
Thread Tools Display Modes
 
Old 04-16-2020, 09:36 PM   #1
Member
 
Brand: Thor Motor Coach
State: Idaho
Posts: 77
THOR #7541
Dead Crank Battery

We leave our Thor Chateau 2017 29G Class C motor home plugged in, stored right next to the house.
It wouldn't crank at all, so I used the emergency start switch and got it running.
I could not find any appliance that was left on. I did find that the radio in the bedroom would not turn on at all, even when the "truck" motor and/or the generator was running. Could this be a source of battery drain?
2nd question: when you use the emergency start switch are you powering off the RV house batteries?
3d question: any other likely suspects for battery draining?
I realize that my crank battery might need replaced, but would like to explore first.
Thanks in advance. This is a great forum.

__________________
Blindcoyote is offline   Reply With Quote
Old 04-16-2020, 09:44 PM   #2
Senior Member
 
Judge's Avatar
 
Brand: Thor Motor Coach
Model: 2020 Magnitude SV34
State: Florida
Posts: 3,355
THOR #12751
First, some Class C's do not charge the chassis battery when plugged into shore power. Your coach would need to have a Battery Isolation Manager that monitors both the house and chassis batteries and uses a microprocessor to determine when coach should charge the chassis battery when on shore power. You should get the schematics for your coach so you can verify whether you do or don't have a Battery Isolation Manager. It would be near your house batteries and could look something like the attached picture. Someone with your model can confirm whether your model has a BIM or not.

The chassis battery is not tied to the coach electrical system directly so only the house batteries are being used when you use 12V in the coach itself. This is done so you don't accidentally drain the chassis battery and not be able to start the engine.

When you use the Emergency Start Switch, it enables a relay to tie the house batteries to the chassis battery to boost it to help start the engine. When you release the button the relay turns off the the connection between the house and chassis batteries is broken.

You either have a bad chassis battery or something was left on like the parking lights, headlights, dome light, etc. I would put a charger on your chassis battery and then test it to see if it is bad.
Attached Thumbnails
Click image for larger version

Name:	Screen Shot 2020-04-16 at 6.05.09 PM.png
Views:	81
Size:	316.7 KB
ID:	23346  
__________________
Judge is offline   Reply With Quote
Old 04-16-2020, 09:47 PM   #3
Senior Member
 
Brand: Thor Motor Coach
Model: Four Winds 31W
State: Michigan
Posts: 542
THOR #9522
Not sure about yours,but my 31W class C doesn't maintain the chassis battery while plugged into shore power. Confirmed by Thor it's by design. So I plug a small battery maintainer into the AC oulet under the dinette and use a 12V plug into the cigarette lighter socket on the dash.
__________________
Pete and Carolynn Foss from Oxford, MI
2018 Four Winds 31W
1999 Aero Cub F-21 trailer
1977 Tioga 24 foot RV
petefoss is offline   Reply With Quote
Old 04-16-2020, 09:49 PM   #4
Senior Member
 
Brand: Thor Motor Coach
Model: Four Winds 31W
State: Michigan
Posts: 542
THOR #9522
FYI my chassis battery will drain in 4 to 6 weeks otherwise
__________________
Pete and Carolynn Foss from Oxford, MI
2018 Four Winds 31W
1999 Aero Cub F-21 trailer
1977 Tioga 24 foot RV
petefoss is offline   Reply With Quote
Old 04-16-2020, 10:15 PM   #5
Senior Member
 
Brand: Thor Motor Coach
Model: Hurricane 29M
State: Texas
Posts: 1,985
THOR #11781
In my last coach, a sob class c, the chassis battery would go dead in a couple of months if I didn't start it monthly.
__________________
Lt Keefer
2018 Hurricane 29M
CHF, Saf-T-Plus, SumoSprings
Lt Keefer is offline   Reply With Quote
Old 04-16-2020, 10:42 PM   #6
Senior Member
 
Brand: Thor Motor Coach
Model: 29h outlaw
State: New Jersey
Posts: 465
THOR #5248
I would go for a bad battery. Your coach is a 2017,most likely on a 2016 chassis.
That means the battery is four years old. Just like your car how many years can you expect from it. Especially if itís not run daily.
__________________
Trkyte@msn.com is offline   Reply With Quote
Old 04-19-2020, 01:33 PM   #7
Senior Member
 
Judge's Avatar
 
Brand: Thor Motor Coach
Model: 2020 Magnitude SV34
State: Florida
Posts: 3,355
THOR #12751
I forgot to mention in my earlier post.....

When I had my 2018 Outlaw 29H, the chassis battery was not charged on shore power.

I installed Trik-L-Start and it allowed my chassis battery to be maintained by the house batteries and charger.

http://www.lslproducts.net/TLSPage.html


It worked great and I never had to keep the chassis battery on its own charger.
__________________
Judge is offline   Reply With Quote
Old 05-02-2020, 06:26 PM   #8
Junior Member
 
Brand: Thor Motor Coach
Model: Chateau 26B
State: Montana
Posts: 9
THOR #6733
That's what happened to me with 2017 26b Chateau. Battery shot, had to replace.
__________________
Chateauduchien is offline   Reply With Quote
Old 05-02-2020, 06:42 PM   #9
Senior Member
 
Brand: Cruiser
Model: Georgetown 30x3
State: Idaho
Posts: 223
THOR #17441
Quote:
Originally Posted by petefoss View Post
Not sure about yours,but my 31W class C doesn't maintain the chassis battery while plugged into shore power. Confirmed by Thor it's by design. So I plug a small battery maintainer into the AC oulet under the dinette and use a 12V plug into the cigarette lighter socket on the dash.
Many (most) cigarette lighter sockets are not connected when the key is off. Be sure to verify.
__________________
IDguy is offline   Reply With Quote
Old 05-02-2020, 07:30 PM   #10
Member
 
Brand: Thor Motor Coach
Model: chateau 23U
State: Florida
Posts: 41
THOR #1241
Knife switch on chassis battery

I use a battery-mounted knife disconnect switch on the chassis battery ground post for storing the unit for months. With no parasitic drain on the battery, it will self discharge only 5-10 percent per month. I've never had a starting problem after storage.

These switches are available at auto parts stores for about $25. I would only use the knife-type due to the large starting current. Image attached.


Quote:
Originally Posted by Blindcoyote View Post
We leave our Thor Chateau 2017 29G Class C motor home plugged in, stored right next to the house.
It wouldn't crank at all, so I used the emergency start switch and got it running.
I could not find any appliance that was left on. I did find that the radio in the bedroom would not turn on at all, even when the "truck" motor and/or the generator was running. Could this be a source of battery drain?
2nd question: when you use the emergency start switch are you powering off the RV house batteries?
3d question: any other likely suspects for battery draining?
I realize that my crank battery might need replaced, but would like to explore first.
Thanks in advance. This is a great forum.
Attached Thumbnails
Click image for larger version

Name:	knife switch.JPG
Views:	50
Size:	17.3 KB
ID:	23544  
__________________
RVGeek is offline   Reply With Quote
Old 05-02-2020, 08:26 PM   #11
Member
 
Brand: Still Looking
Model: Newmar Ventana LE
State: Tennessee
Posts: 77
THOR #16834
My 2017 Thor Citation Sprinter did not charge the chassis battery when on shore power. There is a chassis battery disconnect on Sprinters right above the accelerator pedal. I found that current drains on the chassis battery include, the remote keyless entry, the dome lights and possibly the ECM as they say to wait 10 minutes after engine shutoff before pulling the disconnect.

I learned the hard way. Three months after not pulling the disconnect, the chassis battery was almost completely drained. The dome light would barely come on and when I tried to start the engine (diesel), there wasn't enough power to turn over the diesel. Finally had to buy a Schumacher XP750C booster to get it started. All this the night before leaving on a trip.
__________________
Mr.Good is offline   Reply With Quote
Old 05-02-2020, 10:18 PM   #12
Senior Member
 
Brand: Thor Motor Coach
Model: Four Winds 31W
State: Michigan
Posts: 542
THOR #9522
Quote:
Originally Posted by IDguy View Post
Many (most) cigarette lighter sockets are not connected when the key is off. Be sure to verify.
Agree, I was a bit surprised and glad to find mine are. But that also means we have to remember to unplug chargers, etc.
__________________
Pete and Carolynn Foss from Oxford, MI
2018 Four Winds 31W
1999 Aero Cub F-21 trailer
1977 Tioga 24 foot RV
petefoss 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 07:45 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2022, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0 PL2