How To Wire Redarc In-Vehicle BCDC Battery Charger To Charge 2 Batteries With Smart Alternator

Question:

Your video on the installation of this unit in a travel trailer was very good except it left one scenario unanswered and that was to show where to run and connect the blue wire from the Redarc to if you have a smart alternator, which I have. Would you please give me a detailed explaination how to do this? Also I would like to charge not only my travel trailer battery with this Redarc but also at the same time charge a AGM battery that I will have in the back of my Jeep Grand Cherokee which I will use to power a Dometic portable frige/freezer. If you could please tell me again in detail how I would do this. Will this model have enough amps for what Im planning on doing or do I need to get the next version up from this one? I do plan on purchasing this system and components from eTrailer once I know what Ill need. Thank you for the help.

asked by: Steven R

Expert Reply:

The Redarc In-Vehicle BCDC Battery Charger part # 331-BCDC1225D will still install the same with a smart alternator. The blue wire will still go the vehicle's ignition. The charger will recognize that the car battery is still receiving a charge from the alternator even if the voltage drops like it does with smart alternators. When the voltage does drop while accelerating the charger will adapt to the drop and still pull power.

The only way to charge two batteries at the same time with the Redarc battery charger part # 331-BCDC1225D is two wire the two batteries in parallel as long as they are both 12V and the same chemistry. I have attached a diagram of how to wire two batteries in parallel and the diagrams for the wiring the Redarc. You would just wire the two batteries as parallel in replace of the single battery on the Redarc diagram. You wont have an issue charging both batteries with this charger.

expert reply by: Heather A