12V DC Cutoff Switch Operation

westysplace

Member
Joined
Jun 11, 2011
Posts
29
My 2008 X210 Fun Finder has a 12V DC cutoff switch mounted in the front pass-through storage compartment. Does this switch, in the cutoff position, still allow charging of the batteries while towing with the vehicle? Believe it or not I couldn't get an answer either from the dealer or my generic Cruiser RV owner's manual. Any feedback would be appreciated!
 
On my '08 210WSB, if you use the disconnect to isolate the trailer load from the battery, you also isolate the TV's connection to the battery. On mine, I actually took the black cover off the unit (where the disconnect is mounted) in order to a) see what the heck was in there and b) to fashion a guard for the darn switch so that stuff moving around in the pass- through wouldn't bump the switch into the "disconnect" position. My switch is wired across the hot line from the battery as it comes up into the trailer and the main bus for the 12v system. This is also where the 7pin connector's wiring enters the "system". The disconnect is between the TT's wiring bus and the battery's hot cable. Disconnect is a true disconnect. No battery connection to anything except the ground to the chassis.

Using the disconnect on mine is the same as removing the battery from the TT. Utter and complete "disconnect". Not even the breakaway switch is connected (another reason for my making the shield to prevent "accidentally" disconnecting the battery - keep the battery in the charging circuit and keep the breakaway switch powered). I made a "U" shaped shield with ears out of bar aluminum ~2" tall and pop-riveted it to the black box. I can reach over it to manipulate the switch, but, it can't be accidentally activated by anything sliding into it.
 
12V DC Isolation Switch

That is very interesting. You would think that the fuse protected voltage supply side including the converter, battery systems (vehicle & trailer) and breakaway switch could be designed so that they are not affected by the isolation switch. Battery charging could take place no matter what the position of this switch. After all, the idea behind this switch is, I think, to keep from slowly draining the battery down via 12V DC detectors and other monitoring equipment, etc. when not in use and another power source is unavailable. I know it is standard practice to disconnect the tow vehicle electrical from the trailer when parked up and on 120V AC. So this isolates the vehicle battery from being possibly drained.
Based on your discussion I went ahead and fashioned a spacer which fits behind the knob and keeps it in the open position while towing or when need be. I simply took a thick stiff elastomer gasket and split it to fit nicely over the stem behind the pull knob. The only problem is it will probably grow legs over time!
Thanks for the discussion.
 
Re: 12V DC Isolation Switch

westysplace said:
That is very interesting. You would think that the fuse protected voltage supply side including the converter, battery systems (vehicle & trailer) and breakaway switch could be designed so that they are not affected by the isolation switch. Battery charging could take place no matter what the position of this switch. After all, the idea behind this switch is, I think, to keep from slowly draining the battery down via 12V DC detectors and other monitoring equipment, etc. when not in use and another power source is unavailable. I know it is standard practice to disconnect the tow vehicle electrical from the trailer when parked up and on 120V AC. So this isolates the vehicle battery from being possibly drained.
Based on your discussion I went ahead and fashioned a spacer which fits behind the knob and keeps it in the open position while towing or when need be. I simply took a thick stiff elastomer gasket and split it to fit nicely over the stem behind the pull knob. The only problem is it will probably grow legs over time!
Thanks for the discussion.

I did the same, except I took the knob off slid on a washer with an attached cable to the spacer. That way it cant walk away
 

Try RV LIFE Pro Free for 7 Days

  • New Ad-Free experience on this RV LIFE Community.
  • Plan the best RV Safe travel with RV LIFE Trip Wizard.
  • Navigate with our RV Safe GPS mobile app.
  • and much more...
Try RV LIFE Pro Today
Back
Top Bottom