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Installing a Battery on a Trailer and Wiring it to Run Interior Trailer Lights  


I want want to install a separate, standard 12 volt deep cycle trailer battery to operate two small interior lights. What I need? I have 2006 toyota truck with 7-pin connector ant trailer is a Hallmark V-Nose 7x12foot trailer with a 7-pin connector..I know I will need a battrey, I want install a small battrey on the outside in the trailer in hitch area.


Expert Reply:

I recommend a 12 volt car battery rather than a breakaway battery because you may end up needing the larger battery down the road.

What you will do is attach a battery box (see link for options) to the trailer frame. From the trailer side 7-Way connector, there will be a wire attached to the pin in the 11:00 position (if looking at the face of the plug). This is the 12 volt circuit. You can attach that to the positive terminal of the battery. It will maintain the battery but it will not up charge it.

Also you will want to ground the battery to the trailer frame.

From the wiring on the interior lights, you will want to attach the power wires to them to a switch like # BL0108-00. Mount the switch in the trailer. Then, on the other terminal on the back of the switch, attach a wire and route it to the outside of the trailer over to the battery. Attach it to the positive battery post. Flip the switch and the lights will come on getting power from the battery.

To up charge the battery at home or when shore power is available, I recommend the CTEK battery charger, # CTEK56353.

expert reply by:
Michael H

Freddie P.


i want to change out the small 12v battery to a large deep cell battery for lights and fans. I need to know what i need and will it mess up anything. the purpose is so I only have one battery for everything. I know i will have to get a bigger battery box for the outside but i believe i can use the same 7way plug that i have.

Etrailer Expert

Chris R.


Other than physically changing out those connections to the battery, you really shouldn't need to do anything else when switching to a larger unit.

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