Quark

[BrianG]

A UBEC stands for Universal Battery Eliminator Circuit. It is essentially a small switching power supply that converts your high battery voltage to 5v or 6v for your receiver and servos.

The switching nature makes it very efficient compared to a typical BEC inside the ESC, which is a linear regulator. With a linear regulator, the act of stepping down the voltage can create LOTS of heat, and gets worse as the battery voltage gets higher and the servo load increases. Eventually, it thermals and shuts down. Not good.

At anything over 2s lipo or 7 cells, the built-in ESC BEC should be disabled and a UBEC used instead.