Dolphin Booster: A real DC charger for your 24V batteries
Booster DC/DC double output
Dolphin Chargeur Booster DC-DC 12/24V-30A
Amazon.com: Renogy 12V 40A DC to DC On-Board Battery Charger for Flooded, Gel, AGM, and Lithium, Using Multi-Stage Charging in RVs, Commercial Vehicles, Boats, Yachts, 40A : Automotive