How to Charge Trailer Battery Through 7-Way Connector

Question:

I have a 2000 Chevy 1500 Silverado with the towing package, and a factory 7 pin connector. I need to charge a 12v marine battery that powers tongue jack and lights in a enclosed cargo trailer/toy hauler. I want the trailer battery to charge from the tow vehicle when the 7 pin is connected. Do I need some kind of an adapter, or is the 12 volts at the 7 pin connector on the charging circuit?

asked by: Ernest C

Expert Reply:

If your battery is already connected to the 12V power circuit then it is already receiving a charge form the battery/alternator on your 2000 Chevy Silverado 1500 (see attached pictures).

With that being said, since your trailer battery is far enough away from your alternator it is just receiving a trickle charge that will only charge it slowly and not up to 100% capacity due to the voltage drop. To remedy this you either need to use a charger like the CTEK MULTI US 7002 # CTEK56353 for when your trailer is parked near AC power or an on-board charger like the recommended Redarc In-Vehicle BCDC # 331-BCDC1225D to charge it from your alternator.

Both of these basically do the same thing in that they monitor and charge the battery completely. The biggest difference is that the CTEK can only receive power when plugged into an AC wall outlet while the BCDC takes that trickle charge from your alternator and boosts it so that your battery actually charges normally. Another plus side of using the BCDC is having the ability to integrate a solar panel like part # 34273836 so that you are getting power from 2 different sources to help charge and maintain your trailer battery. The BCDC also has an integrated isolator so that the battery stops pulling power when the vehicle is off which prevents you from depleting your vehicle battery.

expert reply by: Jon G