7-Way Power Wire

[Figmo]

So, apparently, the amperage going to the aux power wire on the Bronco 7-way is pretty anemic. I want to use it to keep an aux battery charged in the trailer. From reading other posts, this works. Albeit very very slowly.

Anybody ever run a dedicated wire from under the hood back and replace the aux power wire on the 7-way plug? Was thinking like a 12ga or 10ga wire that could carry a little more current.

If so - where would you tie something like this in? Direct to battery? Somewhere off the fuse box? Back of alternator?

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[robepa]

I am running my own wire, you will need a DC to DC charger to make it work for a few reasons.
The alternator in the Bronco is smart, so it will not output 14 volts unless if thinks it is needed. Chargers like redarc have a ignition wire that let it know when to create that demand.

The voltage drop from the alternator even with large gage wire will mean the voltage at the trailer battery may be insufficient to charge the battery.

 

[Figmo]

DC2DC charger on the Bronco? Or in the trailer connected to the 7-Way?

I was thinking of mounting the charger in the trailer and just using the aux power line to feed into it.

 

[robepa]

You want the charger to be close to the battery you are charging, so in this case in the trailer. Redarc makes a good one (but pricy) https://www.redarcelectronics.com/us/trailer-battery-charger.

 

[JKBL4]

I ran a 4 awg which I will connect to a dc-dc charger and use the factory aux wire as the “ignition wire” for the charger.

 

[Figmo]

I ran a 4 awg which I will connect to a dc-dc charger and use the factory aux wire as the “ignition wire” for the charger.

I think you are right. The charger I got is a 20amp charger which “normally“ wouldn’t require such a big wire. (10 or even 12 awg would work) but given how long the wire needs to be - I like your idea of a bigger wire to reduce the voltage loss.

BTW: This is the charger I’m using: Vicoffroad ATEM Power 12V 20A DC to DC Battery Charger. Way less money than the higher end models but still has the features I need (ignition wire, solar inputs, etc). Time will tell if it holds up to the test of time and trails.

One last question: Where did you connect on the Bronco side? Direct to battery?

 

[JKBL4]

I think you are right. The charger I got is a 20amp charger which “normally“ wouldn’t require such a big wire. (10 or even 12 awg would work) but given how long the wire needs to be - I like your idea of a bigger wire to reduce the voltage loss.

BTW: This is the charger I’m using: Vicoffroad ATEM Power 12V 20A DC to DC Battery Charger. Way less money than the higher end models but still has the features I need (ignition wire, solar inputs, etc). Time will tell if it holds up to the test of time and trails.

One last question: Where did you connect on the Bronco side? Direct to battery?

Yep direct to the battery with a fuse close to the battery.

 

[robepa]

Blue Sea Systems has a DC wire gage calculator (http://circuitwizard.bluesea.com/#) assuming 20 amp, 3% voltage drop and a total length of 50 ft it recommends 4 gage, 10% and 40 feet is 10 gage.

 

[NVCowboy]

Screw it. My four pins gonna work as soon as I fix one thing. Thinking of Installing solar on the trailer, and stop sweating the 7 pin.

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