What is the most efficient way to step down 48V to 12V? I have a power supply that can output 48V at 40 amps. Assuming the power supply is perfect, that gives me 1920 watts. However, I'm powering some RC equipment such as ESCs and brushless DC motors that need 12V. The perfect step down would be able to push 12V at 160 amps. Is there anything more efficient than the regulators I have found which at most can push 12V at 12 amps? 

The ones I have found: 

* [http://www.amazon.com/Converter-Regulator-48V-12V-120W/dp/B00965W4TU](http://rads.stackoverflow.com/amzn/click/B00965W4TU)
* <http://www.powerstream.com/dc48-12.htm>