Why Do You Need Ubec?; Specification; Features - Hobbywing 3A UBEC Instruction Manual

Instruction Manual
Item-No. 86010010

1. Why do you need UBEC?

The UBEC is a switch-mode DC regulator separated from ESC (ESC---Electronic Speed
Controller for brushless/brushed motor), it will take high-voltage (5.5V to 26V) power from your
battery pack and convert it to a consistent safe voltage for your receiver, gyro and servos.
For traditional speed controller with a built-in BEC, it will very likely have only a limited ability to
supply power to your receiver and servos without overheating. If you are using a high-voltage
battery pack or have heavy servo load, you should consult the ESC specifications to determine
what the stated recommendations or limitations are. In general, if you are using a 4 cells lithium
battery pack, or more than a 12 cells Nickel based battery pack, you should consider using an
UBEC because in such a case the built-in BEC of the ESC can support only 2 servos, which
means it is not suitable for RC helicopter and big aircraft.

2. Specification:

2.1. Output: 5V/3A and 6V/3A switchable
Ripple: <50mVp-p(@2A/12V)
2.2.
2.3. Input: 5.5V-26V (2 to 6 cells Lipo battery pack, 5 to 18 cells NiMH battery pack)
2.4. Size: 51mm*16.6mm*8.5mm (length*width*height)
Weight: 11.5g
2.5.

3. Features:

3.1. The UBEC is an advanced switching regulator with over-current and over-heat protection
function, and the maximum efficiency of the system is nearly 90%.
3.2. The small size and the light weight make it very convenient to use.
3.3. The comparison of linear BEC and switch-mode BEC: When using a lithium battery pack
more than 3S, a switch-mode BEC has much higher efficiency than linear BEC.
• For a traditional linear BEC, For example, a 4S lithium battery pack has a typical voltage of
14.8V, in order to let BEC output 5V/1A, the current flow into the BEC is at least 1A, so the po-
wer on BEC is 14.8V* 1A=14.8W. But the useful output power is only 5V*1A=5W, so the effici-
ency of the linear mode BEC is just 5W/14.8W=33.8%, the redundant power 14.8W-5W=9.8W
changes to heat, which makes the BEC very hot.
• For a switch-mode BEC in the above case, in order to let BEC output 5V/1A, the current flow
into BEC is only 0.38A (actual test data), so the power on BEC is 14.8V* 0.38A =5.6W, and the
efficiency of BEC is 5W/5.6W=89.3%.
3A Switch-Mode UBEC