Parts Needed to Charge Auxiliary Battery in 2018 Subaru Outback with Vehicle Battery

Question:

I have a 2018 Subaru Outback that has a power socket in the cargo area. I want to charge a 35AHr AGM battery not car or deep cycle marine while the car is running, mostly keeping it topped off bc the battery won’t be used that often. I am a ham radio operator, the AGM battery is for emergency communications purposes. Can I use the 12 volt power socket to recharge the AGM battery while the car is running? If so, what 12 volt socket charging device would I need? I also have a 4 pin wiring setup for towing.

asked by: Shannon

Expert Reply:

Most battery chargers that you'd be looking at are all AC to DC power, so you can't use them off a car battery. A way around this would be to install something like the Redarc Redarc In-Vehicle BCDC Battery Charger - Dual Input - DC to DC- 12 Amp # RED96FR, which will allow you to trickle charge your auxiliary battery through your car battery. I really like the BCDC since it gives you the ability to integrate a solar panel like part # 34273836 so you've got 2 different sources to charge and maintain your auxiliary 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.

I've linked a short review video of the BCDC system that I recommend checking out.

expert reply by: Erik B