Wiring to charge while driving

[fidgetboy]

So here is my query of the day I have 4 pin wiring on my trailer but I would like to be able to charge my battery while driving. Since my truck is wired for both four and seven pin from the factory is it ok take a seven pin extension and modify it to accomodate a line to charge the battery and the 4 pin as well leaving the other two unused. Also, would I need to to put any thing like an inline fuse or ?? between the tow rig and battery. Any comments or suggestions will be appreciated.

[Thomas G.]

I think you are advocating putting a 7 pin connector on your trailer to power the trailer external lights and charge the trailer battery, leaving the brake and back up positions empty.

Sure. You should have a fuse or circuit breaker at the trailer battery in case the wire gets pinched, other wise the trailer battery will light up the wire. Use heavy wire - at least 10 gauge to maintain adequate voltage at the trailer battery to fully charge.

[fidgetboy]

Exactly, thanks for the info.

[Perry J]

Go to an auto parts store and tell them you want a self resetting circuit breaker.
Attach it to the fender or somewhere well near the battery and connect the TV battery to it and run your line from it to the trailer.
If you have a short you don't want a red hot wire in your vehicle.
John

[Thomas G.]

Originally Posted by Perry J

Go to an auto parts store and tell them you want a self resetting circuit breaker.
Attach it to the fender or somewhere well near the battery and connect the TV battery to it and run your line from it to the trailer.
If you have a short you don't want a red hot wire in your vehicle.
John

Right, you need a fuse or a circuit breaker both at the trailer battery and at the tow vehicle battery. Either one has the capacity to overheat a shorted wire.

[fidgetboy]

Good to know. Sounds like next weeks project. Thanks guys.

[Kevin K]

Just did this on my truck.
I bought a continuous solenoid relay
Run a 10 gauge wire back to the trailer plug.
Need 30 amp fuse between positive battery and terminal 1 on the solenoid.

Solenoid terminals
1 Positive
2 Ground
3 Wire to back of trailer
4 Switch (hot wire when Ignition is on)

[Thomas G.]

Since my truck is wired for both four and seven pin from the factory

I'm curious. If a truck comes pre-wired with a 7 pin connector does that usually include the relay, fuse and wiring from the battery back to the rear connector to charge the trailer battery??

[mszabo]

If it's prewired from the factory, it will have it's own protective circuit.
Mike

[Byron Kinnaman]

Originally Posted by Thomas G.

I'm curious. If a truck comes pre-wired with a 7 pin connector does that usually include the relay, fuse and wiring from the battery back to the rear connector to charge the trailer battery??

My factory tow package 2005 Dakota doesn't have a relay. It does have a 30 amp fuse. It's on the fuse block. All trailer lights are run through fuses and relays, including turn signals.

[841K9]

Originally Posted by Byron Kinnaman

My factory tow package 2005 Dakota doesn't have a relay. It does have a 30 amp fuse. It's on the fuse block. All trailer lights are run through fuses and relays, including turn signals.

Ditto for the 24volt NATO crap on my Blazer.