Wiring a Trailer Mounted Winch to a Trailer Battery and Vehicle Battery

Updated 08/28/2013 | Published 08/25/2013

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12 Gauge Wire - Black Primary - Per Foot

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Question:

I use an independent battery to runI the winch on my open car trailer. The winch and battery are mounted in a tongue tool box. Currently I am charging that battery at home before each use only. What do I need to do to allow my tow vehicle system to charge the winch battery when going down the road and then isolate that battery from tow vehicle when winching to keep from draining tow vehicle battery. 1 If I hook the black battery wire in my trailer harness to the winch battery, will this allow charging to the winch batterry? 2 Will my ignition switch isolate them when off? 3 Do I need a two battery universal isolater? 4 Do I need a isolater solenoid? 5 Also, do you see a problem with using this same winch battery as my hitch safety disconnect switch power source? I do not use the trailer very often but, I want optimum performance and safety when I do. I have just painted the trailer and I am in the process of updating all wiring. Please advise as to your recommendations!

asked by: Roger S

Expert Reply:

I have just what you will need. I have linked an FAQ article that explains the various ways to wire a winch. You will need the second half of the page titled Option 2: Wiring the Winch to a Separate, Trailer-Mounted Battery. I have also included a picture that shows how it would all go together.

You will need a battery isolator, # PK5231201, some wire like # 10-1-1 or # 12-1-1 sold in 1 foot increments, and a 40 amp circuit breaker # PK54540. You will wire it all up like in the picture.

Please note that a vehicle battery and the wiring will provide a maintenance charge only to the trailer mounted battery. The vehicle battery, alternator, and wiring is not strong enough to push enough amperage back to charge up the trailer mounted battery. The trailer connector must be disconnected from the vehicle before operating the winch to avoid damaging the vehicle battery or wiring.

To charge up the trailer mounted battery you are doing it right by charging it up using a battery charger and shore power. If you are interested in the latest in battery charging technology I recommend CTEK charger # CTEK56353. Three or four of us here own this charger and it is, in a word, awesome. It will not overcharge a battery and will actually help to extend battery life.

You could use the same battery for the winch and break away system but you should use a dedicated battery from the break away system. The reason is that if the shared battery were discharged too much the break away system may not work or work well enough to do its job.