How To Charge A Trailer Battery From Your Vehicle While Towing
Question:
I have a 4 pin on my Subaru and small tear trailer with a 4 pin as well. Do not need brakes but I would like to charge the trailers battery while I drive. I think I would need to convert both the cars and trailers 4 pin to 7 pin. I think Id need a 4 pin to 7 pin adapter on the car-end and then a 7 pin with junction box on the trailer-end. Could I then run a wire from the black junction to t he battery to charge it?
asked by: Sam S
Expert Reply:
To easiest way to set up your trailer and vehicle to charge your battery would be to use the Trailer Wiring 7-Way Upgrade Kit w/ Junction Box and RV Style Connector Item # HS381-9000. This kit allows you to convert your trailers 4 pole to a 7 pole. The junction box comes with the 7 pole cable. You would just need to cut the four pole plug off, add ring terminals to the wires, and attach the wires from the trailer to the correct pins in the junction box. Including the wire that needs to run to your camper battery.
To convert your vehicle to a 7 pole I recommend the following items:
The 7-Way RV Upgrade Kit for Trailer Brake Controller Installation # ETBC7. Your current four pole plug connects to the four pole plug on the 7 pole adapter to provide light functions to your trailer. Since you are not needing the brake wire or reverse wire, those can be taped up in the bundle. The black and white wire are your power and ground. The white wire can be grounded anywhere on the frame as long as it is a clean piece of metal. The black wire needs to be extended up to the engine compartment, connected to a circuit breaker, then connected to the positive side of the battery.
A Replacement In-Line Fuse Holder for Curt Wiring Harness - Qty 1 Item # C58470-1 and a Curt 15-Amp Blade Fuse - Quantity 1 Item # C58450-1 on your power wire connected to your camper battery.
I recommend using Deka Heat Shrink Butt Connector - 12-10 Gauge - Nylon Insulation - Yellow - Qty 5
Item # DW05745-5 for the wire connections to your fuse holder
Products Referenced in This Question
Replacement In-Line Fuse Holder for Curt Wiring Harness - Qty 1
- Accessories and Parts
- Wiring
- Fuse Holder
- CURT
more information >
Deka Heat Shrink Butt Connector - 12-10 Gauge - Nylon Insulation - Yellow - Qty 5
- Wiring
- Wire Connectors
- Butt Connectors
- 12-10 Gauge
- Deka
more information >
Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
- Accessories and Parts
- Trailer Brake Controller
- Installation Kits
- etrailer
more information >
Wiring Kit for Hydrastar Electric Over Hydraulic Actuators
- Accessories and Parts
- Brake Actuator
- Disc Brakes
- Hydraulic Drum Brakes
- Wiring
- Hydrastar
more information >
Product Page this Question was Asked From
Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps
- Trailer Wiring
- Wiring Adapters
- Multi-Function Adapter
- 4 Flat
- Plug and Lead
- 4 Flat
- 7 Round - Blade
- CURT
more information >
Featured Help Information
Instructions
Continue Researching
- Shop: ModuLite Installation Wiring Kit
- Shop: Pollak 10-Terminal Junction Box
- Shop: Junction Box and Installation Kit for Autowbrake Trailer-Mounted Electric Brake Controller
- Shop: Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
- Shop: 10 Gauge Primary Wire - Red - per Foot
- Shop: Hopkins Endurance Multi-Tow 4-Way Flat to 7-Way RV Trailer Adapter w/ 4-Way Vehicle End Plug
- Q&A: How to Use a 4-Pin to 7-way Trailer Connector Such as C57672
- Video: Review of Curt Wiring - In Line Fuse Holder - C58470-1
- Shop: Deka Jacketed 2 Wire, 10 Gauge, Brake Wire - per Foot
- Video: Spectro Trailer Wiring Junction Box Installation
- Shop: RV Interior Lighting
- Shop: Spare Tire Cover
- Shop: RV Covers
- Video: Classic Accessories Custom Fit Spare Tire Cover Review
- Shop: Brake Controller
- Shop: Trailer Wiring
- Video: Tekonsha OEM Replacement Vehicle Wiring Harness Installation - 2018 Toyota Highlander
- Q&A: Adding 7-Way Trailer Connector to 2016 Toyota Highlander
- Q&A: Comparing Trailer Hitches and Parts Needed To Tow a Trailer With a 2018 Toyota Highlander
- Q&A: What Wiring Harness Do You Recommend For My 2021 Lexus RX 350 With Factory Tow Package
- Q&A: Recommendations For Mounting A 4 And 7 Pin Adapter To 2021 Ford Bronco Factory Hitch
- Q&A: 7-Way and 4-Way Trailer Wiring Harness Recommendation for 2015 Toyota Highlander
- Q&A: Autowbrake Electric Brake Controller VS Curt Echo Wireless Trailer Brake Controller
- Video: Thule Bike Carriers Stay-Put Cradle Replacements Review
- Video: Thule Bike Racks Replacement Cradle Strap Review 852-3006-001
- Shop: RV Power Cord
- Shop: RV Electrical
- Video: Hollywood Racks Hitch Bike Racks HR740-P Review