Can 12V Feed from Vehicle 7-Way Overcharge Trailer Battery

Updated 03/19/2020 | Published 03/18/2020

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NOCO Genius Smart Battery Charger - AC to DC - 6V/12V - 10 Amp

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2.5-Watt Solar Battery Charger

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Question:

If I hook up the 12 v aux power supply from the 7 pin directly to the trailer battery and then ground the battery to the trailer frame, do I need a product in between the aux power and the trailer battery to make sure the trailer battery doesnt overcharge on a longer trip?

asked by: Greg

Expert Reply:

You don't need to install any other parts in line with your 12V trailer battery line. Because the current being sent through the 7 pin power wire is so low, it acts more like a trickle charge to simply keep your battery topped off. It is not powerful enough to actually provide a full charge to your trailer battery, so it couldn't overcharge it even during a long trip.

The Breakaway Kit Battery Charger # 20011 is used to prevent overcharging the smaller battery in a breakaway kit, like the Hopkins # HM20001.

To actually charge a depleted trailer battery, you'll need something like the NOCO Genius Battery Charger and Maintainer # 329-GENIUS10, which draws power from a wall outlet to quickly charge and maintain your trailer battery and has built in technology to prevent overcharging.

If you don't have access to shore power, you can instead use a solar powered battery charger, like # PTW2997.

expert reply by: Carla M