Amazon.co.jp: DC 12V to DC 24V Boost Voltage Converter Regulator Adapter 9-20V Input Voltage Range High Performance Automotive Boost Power Supply : DIY, Tools & Garden
Amazon.co.jp: 12V-24V dcdc converter boost, trans boost 5A 120W waterproof with power regulator fuse, 12V regulator golf cart led light motor truck vehicle boat etc. (accepts DC9-20V input) : Electronics
Amazon.co.jp: SEAFRONT DC-DC Converter, 48V to 12V 10A 120W Buck Module Buck Power Converter for Car LED Display, Fan : Automotive
Amazon.co.jp: Power Module 12V to 6V Converter Back Car Power Supply Voltage Converter Regulator 3A 18W Waterproof Step-Down Bolt Power Module Converter : Industrial & Scientific