同期整流方式のDCコンなら、効率90%以上は余裕だしな。

10V-50V to 5-35V DC Buck Module Step Down Converter synchronous rectification
https://ebay.us/HDorHg

200W 15A DC-DC 8-60V TO 1-36V Synchronous Buck Converter Step Down Module US
https://ebay.us/FPSWfM