BEC/UBEC is the core power supply module for drone electronic speed controllers. Beginners can easily get confused or make mistakes in selection. This article simplifies its definition, function, and selection methods.
1. Core Definition: What are BEC and UBEC?
Both are DC buck voltage regulation modules, converting the high-voltage battery of the drone to 5V/6V to power low-voltage devices. The core difference lies in the integration method and performance.
1. BEC: Integrated Buck Module
Integrated into the electronic speed controller, there are linear types (1~3A, low efficiency, suitable for small machines, requires heat dissipation) and switching types (≥3A, high efficiency, suitable for medium and large machines).
2. UBEC: External High-Power Step-Down Module
Independent external, high-performance switching type, ≥5A, high efficiency, suitable for large loads, high volume cost, requires anti-interference.
Key Distinction: BEC vs UBEC
BEC (built-in, lightweight load); UBEC (external, enhanced, heavy load), do not use simultaneously.
2. Core Role: Why are BEC/UBEC indispensable?
Low-voltage equipment cannot withstand high voltage; its main functions are voltage reduction and stabilization, and simplifying power supply, specifically in three points:
- Step-down and voltage stabilization to ensure normal operation of equipment:Convert to 5V/6V stable output to avoid equipment failure and ensure flight safety.
- Simplify the power supply architecture, reduce weight and cost:No need for a separate battery, reducing weight, lowering cost, and simplifying wiring.
- Overload protection, enhancing flight safety：Overcurrent/short circuit/overheating power-off, protect equipment, reduce accidents.
3. Practical Guide: How to Choose the Appropriate BEC Power?
Core of selection: match the load and leave a margin, the steps are as follows:
- Calculate the total current of low-voltage equipment: add up the current of all low-voltage equipment.
- Reserve a 20%-30% safety margin:Required rated current ≥ total load × (1 20%~30%), to avoid overload.
- Match the output voltage with the device requirements:5V is suitable for most devices, 6V is suitable for high-torque servos, and the rated voltage must be matched.
- Select based on the scenario:Linear BECs for small aircraft, switching BECs/small UBECs for medium aircraft, UBECs for large aircraft, pay attention to heat dissipation and interference resistance.
Key Points to Avoid Pitfalls in Model Selection
Do not pursue high power; some high-voltage electronic speed controllers do not have built-in BEC and need to be configured separately; reserve space for heat dissipation.
IV. Conclusion
Both BEC (built-in) and UBEC (external) are core components of low-voltage power supply for the electronic speed controller, with the function of voltage step-down regulation, stabilizing voltage, and ensuring safety. Key points for selection: match the load, allow for margin, adapt to voltage, and consider the scenario to avoid power supply failure.