Charging Auxiliary Battery from Car Cigarette Lighter or 12 Volt Auxiliary Plug Connector

Published 08/11/2017

Question:

Want to charge extra auxiliary 12v deep cycle agm battery while driving. I am pulling a pop up trailer with a marine battery on the tongue, but want extra power for dry camping. I have had my brake controller installed by etrailer and thought you folks could help me with this issue. Thought I could just charge the 12v auxiliary battery with a female to male cigarette lighter connector. The Subaru Outback has an a cigarette lighter outlet in the back of the car so it would seem to be an easy hook up, but doesnt a deep cycle battery require a 3 stage charge controller? Could you enlighten me on how to solve this dilemma. Thanks PS The break controller is working great. Perfect setup for my Subaru

asked by: Barbara

Helpful Expert Reply:

The 12 volt auxiliary power connections are great for charging a smart phone or running an auxiliary accessory like a DVD player, but these circuits do not have the capability of charging an auto or marine style 12 volt battery.

The auxiliary may be able to provide a small maintenance charge, but if the battery is running certain appliances while in transit, this circuit will not be able to charge up the battery.

The best solution is to use a battery charger, like # CTEK56353. This CTEK charger is designed to charge both auto and marine deep cycle style batteries.

expert reply by: Jared P