12V volt to 48 volt DC/DC battery charger for lead acid and lithium batteries (common negative) 1250 Watts Robust, marine, heavy duty from PowerStream.
240w battery charger 12V 24V 36V 48V and 60V for lithium battery and lead acid battery BBS, ebike batteries, Bafang M620, Bafang M600, Bafang M500, Bafang M510, KT controller with display-GreenBikeKit.com
Amazon.com: dkplnt 12V 24V to 56V 10A 560W DC to DC Charge 48V Battery Converter for Flooded, Gel, AGM, and Lithium, Using Multi-Stage Charging in RVs, Vehicles, Boats, Yachts with Acc Ignition :
MARS 12-48 30 HF multi-voltage battery charger e 12/24V, 36V, 48V 3-30A 1Ph 230 Vac | Polar electronics