Do I Need an Isolating Solenoid to Wire Aux Battery on My Trailer

Question

Question:

Can you tell me how to exactly wire a 12v battery to power my interior lights to my trailer and to my breakaway battery without an isolator. Do you recommend an isolator?

asked by: Carrie R

0

Expert Reply:

There are a few different ways you can wire a 12v battery to power your interior lights and maintain your breakaway battery on your trailer.

You can find the 12v circuit on your trailer's 7 way connector, it's usually a black wire at the 11:00 o'clock position (if you are looking at the face of the plug). Connect that wire to the positive post of the new aux battery, and ground the negative post to the frame. Then you can connect to the aux's positive post to the positive post on the breakaway battery. This will give a maintenance charge on both the aux and breakaway battery when hooked up and towing, but will not charge the battery from dead.

You want to protect the breakaway battery from being drained while using the interior lights, so I do recommend an isolation solenoid like part # PK5231201.

The solenoid will wire in between the aux/new battery and the breakaway battery, with a trigger power source, in this case it can be the running light circuit on your trailer. That way, when your trailer is connected, you can charge the break away and the auxiliary trailer battery, but when not connected the break away battery will not be drained by the auxiliary trailer battery, because the trigger is not completing the circuit inside the solenoid.

If you don't already have a junction box on your trailer I recommend adding one like part # 3375601101, along with ring terminals and wire to make all your connections. This will give you a cleaner look in the end, and make it easier to add any other components or repairs in the future.

expert reply by: Robert C

0

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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&#39;s 12V power feed and route this to the positive terminal on the auxiliary battery, and you will ground the…

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Answer 2

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,…

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Answer 3

You would need a power inverter to allow you to power the 12V LED lights in your trailer with a 115V power source. That could prove to be expensive. I do have another solution that will work for you. To be able to plug into AC power the trailer…

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Answer 4

So the right way for you to do this will depend on how often you're going to use the lights and how many of them there are. If a trailer isn't equipped with a battery, the interior lighting is frequently tied into the running lamp…

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Answer 5

You can put a maintenance charge on your trailer battery with the 12 volt accessory circuit of the 7-way. The 1:00 position of your 7-way carries this circuit. You would just need to run a length of 10 gauge wire like part #10-1-1 (sold by the…

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Answer 6

If the 12V power for the 7-Way connector is active it will pull power when the vehicle is off and installing a Battery Isolation Solenoid #PK5231201 would definitely help you avoid this situation and keep your cargo trailer interior lights running…

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Answer 7

A 4-Way trailer connector has the basic lighting functions only; running lights, left turn signal and brake lights, right turn signal and brake lights, and ground. A 7-Way has these functions and a 12 volt circuit, a circuit for electric trailer…

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Answer 8

If you just need a 4-pin to 7-pin trailer wiring adapter, then you can use part #C57672. This will plug into the 4-pin trailer connector on your brother's vehicle and give him the 7-pin socket for the trailer. Keep in mind, this will only…

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Answer 9

When wiring a trailer connector, it is best to wire by function, as wire colors can vary. We have an excellent wiring diagram on our website, I will provide you a link so you can look at it. If you are looking at the inside of the trailer connector…

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Answer 10

The only difference between 7-Way Utility and 7-Way RV is the color of the wires. The pin outs are the exact same so either would work just fine with the other. If you check out the picture I attached you'll see that the functions are all…

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Answer 11

Since wire color codes are NOT universal, we always recommend wiring by function, rather than wire color. If you look at the Trailer Wiring FAQ article I have linked you to, you can see some diagrams showing the proper way to wire a vehicle and…

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Answer 12

It's a wire color difference but not a function difference on the pins of the 7-way. The difference comes from the fact that the two different styles are representative of two different areas that uses trailers. Traditional is usually seen…

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Do I Need an Isolating Solenoid to Wire Aux Battery on My Trailer

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