How To Charge Towed Vehicles Battery With Tow Vehicles 7 Way Connector

Updated 05/19/2021 | Published 05/17/2021

Products Featured in This Question

2-Wire Trailer Adapter for Go Power Portable Solar Kits

(21)

$18.25

10 Gauge Wire - Blue Primary - Per Foot

(103)

$1.80

Pollak Black Plastic, 7-Pole, RV-Style Trailer Connector - Trailer End

(678)

$6.41

Roadmaster Battery Charge Line Kit for Motorhomes

(134)

$60.97

Question:

Can I use this connector to plug into my 7 to 4 pin trailer adapter to charge the vehicle main battery?

asked by: Steven S

Expert Reply:

The 2-Wire Trailer Adapter for Go Power Portable Solar Kits # GP72VR is specifically for Go Power solar panels so if you don't have one of those then I don't recommend using this.

It sounds to me like you are wanting to use your vehicle's 7 way trailer connector to charge your towed vehicle's battery. If your 7 way already has a pin that has 12v when the vehicle is running then you can simply use that circuit (usually it is the 1 o'clock pin on 7 way). If you don't already have a 12v pin then you first need to run Roadmaster Battery Charge Line Kit # RM-156-75 from the tow vehicle's battery to the 7 way.

Now that your 7 way has 12v power, you can run the 12v wire to the towed vehicle to charge the battery. There are several ways to do this, but I think the best way is to cut off the 4 way connector on your trailer wiring and install Pollak Black Plastic, 7-Pole, RV-Style Trailer Connector - Trailer End # PK12706. Then you can use 10 Gauge Primary Wire - Blue # 10-1-1 (sold per foot) to run from the 7 way connector to your vehicle's battery.

I attached demonstration videos along with a couple wiring diagrams for you to check out.