How To Charge A Trailer Battery With The Tow Vehicles 7 Way Connector
Question:
I have installed an electric jack kit on a trailer that doesn’t have a battery mounted on the trailer. I have mounted a battery to run the jack but my question is how can I keep the battery charged on the trailer to continue to use the electric jack?
asked by: Russ U
Expert Reply:
Your 2006 GMC Sierra should have a 7-way trailer connector so you could tap into the 12v power wire and connect that to your trailer's battery. Keep in mind this will be like a low amperage battery tender to top off the battery, but it will not be a full-blown battery charger and it won't be able to charge it from completely dead.
If your trailer has a 4-way flat connector then you will first need to cut off the 4-way connector and wire in the 7-Way Molded Trailer Wire Connector, 4' Long # H20043 which plug into your truck's 7 way. When wiring into your trailer's 4 way, the wiring code is as follows: white wire is ground, red wire is left turn and brake, brown wire is right turn and brake, green wire is taillights, and the black wire is your 12v power wire which will be ran to the trailer's battery. If your trailer does have a 7-way wiring already, then just find the wire (typically black, but not always) that has 12v power when your truck is running; use Circuit Tester Kit # PTW2993 to test the wires and find the correct one.
You will also want to install Battery Isolation Solenoid # PK5231201 which will not allow your truck battery to be drained and will only charge the trailer battery when your truck is running. This will be wired in between the 12v power wire going from the truck's 7 way and your trailer's battery. I have attached a photo showing how this solenoid will be wired in. You can use 10 Gauge Primary Wire - Blue (sold per foot) # 10-1-1 for extra wiring. I have included demonstration videos to help you with this process, along with a 7-way wiring diagram.
(click to enlarge)
(click to enlarge)
Products Referenced in This Question
Starter Solenoid - SPST - 12 Volt - 100 Amp - Continuous Duty - Grounded
- Accessories and Parts
- Battery Boxes
- Switches and Solenoids
- 100 Amp
- Pollak
more information >
Product Page this Question was Asked From
7-Way Molded Trailer Wire Connector, 4' Long
- Trailer Wiring
- Trailer Connectors
- Trailer End Connector
- 0 - 5 Feet Long
- Plug and Lead
- 7 Round - Blade
- Hopkins
more information >
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