A BEC-equipped ESC meant for airplane use often incorporates a low-voltage-cutoff (LVC) circuit which can sense the voltage drop caused when the battery has little charge left.
RC BECs in their simplest form use a linear fixed voltage regulator with its standard circuit suggested in the manufacturer's datasheet – usually the power supply of the receiver needs 5 V. Low-dropout types are preferred – especially for batteries with only a few cells.
More recent uses for RC BECs are converting higher-voltage lithium polymer battery packs to 12 V. This has occurred due to the increased popularity of camera equipment for FPV use.
See Voltage regulator BECs are also used in some motorcycle and ATV applications to reduce the weight penalty involved in carrying a battery.
The battery is typically replaced by one or more large but light-weight capacitors which smooth out the fluctuating electrical pulses coming from the alternator, without themselves generating power.