Outback battery isolator

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Tom in NM
Last seen: 3 days 16 hours ago
Joined: 06/07/2020 - 18:17
Newbie -understanding the issue

First timer with trailers and trying to learn while I wait for my build. To make sure I understand this thread -- the issue is that if the car and trailer batteries stay connected for too long with the car not running it is possible that a trailer battery could discharge and drain the car battery to the point it can't start the engine. Is that correct?

If so, what kind of time are we talking about? Hours, overnight, several days? (Assuming both are good batteries)




ac0gv's picture
Last seen: 4 weeks 1 day ago
Joined: 09/22/2016 - 13:57
It depends...

.... on who wired you tow vehicle. Most will not be connected to the RV if the engine is not running. When in doubt, unplug from the Tow vehicle when parked. My Ford f150 and f350 had no trouble.

Tom in NM
Last seen: 3 days 16 hours ago
Joined: 06/07/2020 - 18:17
I’m wiring the 7-pin

I have a flat four plug, Subaru installed. I'm getting the kit from etrailer to convert to the 7. Since I plan to use the Scamp wireless controller, the only required wiring is a hot wire to the battery (I'm running duplex wiring in case I later decide to use a wired controller). So unless I use one of the suggested relays, there will always be power to the plug. 

Greg A
Greg A's picture
Last seen: 1 week 16 hours ago
SOI-AdministratorLifetime Member
Joined: 11/02/2013 - 20:45
First Item

Whenever I get a new Tow Vehicle, one of the first things I test it whether the ignition switch kills the 7 pin when off. One of these handy lil things makes it very easy to test:  https://amzn.to/3hI0k2Q

Plug it in the 7 pin on the vehicle, turn the vehicle on and check all the functions, turn it off and if all the lights go off then you can leave the trailer hooked up with no drain on the battery.


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