Adding a Battery on an Enclosed Trailer to Power Interior Lights

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Question:

I want want to install a separate, standard 12 volt deep cycle trailer battery to operate my switched interior LED lights. The interior lights are wired to operate only when the ignition in my truck is on and trailer is plugged in. My current configuration is a breakaway battery perhaps I can eliminate this and use a larger battery for both lights and brakes?, 7 pin connectors on 2012 Toyota Truck and Featherlight 7x16. I will use a group 24 deep cycle battery on the tongue of the trailer. Can you tell me how I wire this and what parts I need?

asked by: Scott

0

Expert Reply:

The best way to power the interior lights in your trailer is with its own independent battery. You will not want to use the breakaway battery. The breakaway battery is only designed to operate the breakaway and will drain extremely quickly, they're only required by law to operate your brakes for 15 minutes.

There's a few ways you can install a battery onto the trailer. One is to connect it to the 12 volt pin on the trailer's 7-way in place of the breakaway battery that is currently connected there, then connect the breakaway battery to the new battery. To do this you will need a new battery and some wire like # 10-1-1 which is sold by the foot.

Another is to use a junction box, like # 38656, and mount it to your trailer connecting all of the trailer wiring through it to your 7-way. This requires more rewiring but you end up with a nice, clean set up on the trailer once it's finished. You'll also need some ring terminals, # 44-5310A, to make the connections inside the box.

expert reply by: Charles S

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Josh H.

9/29/2024

Charles I want to be sure I understand this correctly. If I tie into the 7-way in place of the break away with a battery, it will both charge the battery from the vehicle and also send power from the battery to operate the trailers electronics (such as done light) when not plugged into the vehicle?

Kevin C.

9/30/2024

@JoshH The breakaway battery is solely for activating the brakes during a breakaway event and should never be used to power anything else. These batteries typically only hold a small charge that's enough to activate the brakes for 15 minutes so that you can get pulled over safely. Typically the trailer will have a "house" battery that stays on it and powers the 12v DC interior lights or other 12v accessories. If you don't have a battery on the trailer you can splice into the 7-way junction box and wire to your lights to the 12v accessory terminal, but you're limited to the amperage rating of that pin so you could potentially overload the circuit and blow a fuse on your tow vehicle. Running a wire from the 12v accessory pin to the battery would also send a charge to the battery, but you'd still be limited to the amperage rating of the circuit so the trickle charge you get really isn't the best battery charger.

Dean

10/28/2024

Should the battery in a break away brake system on a cargo trailer be the Positive side of a battery hooked to a white groundwire.And the ground wire goes directly to the frame ? Thank you For your anticipated response.

Robin H.

10/28/2024

@Dean your breakaway should have 3 wires and colors can vary. You probably have a black or red wire that will connect to the 12V power, white wire that connects to your main trailer ground, and a blue wire that connects to the brake output circuit. They typically come with instructions so I recommend following the installation instructions for your particular breakaway.

Answer 1

You are correct in your description of how to wire in a new auxiliary battery in your enclosed trailer. You will take the 7-Way's 12V power feed and route this to the positive terminal on the auxiliary battery, and you will ground the second…

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Answer 2

The only way you could power interior dome lights on a trailer without it being connected to a tow vehicle would be to power the lights with a battery like a breakaway battery. How you choose to wire up the batteries will in the end be up to you, but…

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Answer 3

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…

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Answer 4

If you're only wanting to setup AC service in your enclosed trailer then you could choose pretty much any 30 or 50 amp power inlet you wanted and then just run the appropriate gauge wire between the inlet and your panel. You can definitely…

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Answer 5

To run a charge line to your battery you will first need to install a 7-Way on your trailer. This can be done using the Epicord 7-Way Molded Trailer Plug with Junction Box #277-000141. The Black wire in the junction box is the one that will carry the…

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Answer 6

Typically for small interior lights on a trailer people install a car battery in the trailer and run power from it. If you are wanting to run a power wire from a household shore power outlet you'd have to install a panel like the Progressive…

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Answer 7

You will want to run the 12V wire from the 7-way trailer connector to the positive terminal on the larger battery. Then you will want to connect the larger battery to the breakaway battery from positive terminal to positive terminal, using 10 gauge…

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Answer 8

I have attached a photo for you that shows how a 7-way trailer connector is wired. If you take a look at the trailer side trailer connector you will see a terminal labeled "12V Power". If you were to run a wire part #10-1-1 (per foot) from…

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Answer 9

Hey Eric, thanks for reaching out! Ultimately, I'll need more specific info on your trailer (the GVWR would be best), but I can still help you figure out how to choose a weight distribution hitch (WDH). What you'll need to look for is the max…

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Answer 10

Hey Ron, congratulations on the new trailer! I have a Jay Feather myself and love it. You're definitely off to a great start with a weight distribution hitch, it will make a world of difference towing that trailer with your F-150. The Weigh Safe…

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Answer 11

Hey George, we can definitely help you flat tow your 2018 Jeep Wrangler Unlimited JL with a Barricade Adventure HD Front Bumper. Since your bumper has D-rings on the front of it you would need to go with a base plate kit/tow bar adapter that would…

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Answer 12

Since heat rises I would at the very least put a set of the Trailer Vents #HMAV2-AVT2 near the top of the trailer to get the hottest air of the trailer out. What you could do for maximum air flow in your trailer is have a set facing forward in the…

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Adding a Battery on an Enclosed Trailer to Power Interior Lights

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