How to Choose a UBEC or BEC for Clean 5V Power in RC
Choose a UBEC by current draw and cell count. A 3A unit covers a receiver and small servos on 2-6S packs. A 7A unit covers digital servos on 2-8S packs. A 15A unit covers giant-scale models on 6-12S packs. The 3A unit costs $10.99, the 7A unit costs $12.99, and the 15A unit costs $27.99.
Quick facts
| Fact | Value |
|---|---|
| Output voltage (all four units) | 5 V |
| 3A unit input | 2-6S LiPo |
| 5A unit input | 2-8S LiPo |
| 7A unit input | 2-8S LiPo |
| 15A unit input | 6-12S LiPo |
| 3A unit price | $10.99 |
| 5A unit price | $10.99 |
| 7A unit price | $12.99 |
| 15A unit price | $27.99 |
| Full LiPo cell | 4.2 V per cell |
What does a UBEC or BEC do?
A UBEC steps your pack voltage down to a steady 5 V for your receiver, servos, and flight controller.
BEC stands for battery eliminator circuit, and UBEC is the switch-mode version of it.
Your motors run straight off the pack, while your radio gear needs a lower, steady voltage.
Without a UBEC, a receiver fed pack voltage would fail, and a sagging supply can brown out the receiver mid-flight.
What is the difference between a linear BEC and a switch-mode UBEC?
A linear BEC burns the extra voltage as heat, while a switch-mode UBEC converts it with far less waste heat.
A full 6S pack reads 25.2 V, so a linear BEC must drop 20.2 V as heat to reach 5 V.
That heat grows with pack voltage, which is why linear BECs suit small packs and light loads.
A switch-mode UBEC runs cool and efficient, even on 6S and 8S packs, so it suits larger models.
How much current do your receiver and servos need?
Size the UBEC above your peak current draw, not your average draw.
A 3A unit covers a receiver and small servos on a light model.
A 5A unit adds headroom for bigger servo loads and hungrier receivers.
A 7A unit covers digital servos, which can spike current draw well past their rating.
A 15A unit covers giant-scale electrics and heavy-lift multirotors with many servos.
Which UBEC fits your cell count?
Match the UBEC input range to your pack, and check the range before you buy.
The 3A unit accepts 2-6S LiPo input, which covers most small and mid-size electrics.
The 5A and 7A units accept 2-8S LiPo input, which covers larger electrics on 8S packs.
The 15A unit accepts 6-12S LiPo input, which is the range for giant-scale models.
A UBEC wired to a pack above its input range can fail, so never guess the range.
What did we check on the bench?
We matched every price in this guide to the live store price on November 13, 2026.
We counted 1 image on the 3A listing, 2 on the 5A listing, 2 on the 7A listing, and 2 on the 15A listing.
We checked the live listings state 5 V output on all four units.
We checked the live listings state 2-6S input on the 3A unit, 2-8S on the 5A and 7A units, and 6-12S on the 15A unit.
How the options compare
| Item | Input | Output | Price |
|---|---|---|---|
| 3A Switch-Mode UBEC | 2-6S LiPo | 5 V at 3 A | $10.99 |
| 5A Switch-Mode UBEC | 2-8S LiPo | 5 V at 5 A | $10.99 |
| 7A Switch-Mode UBEC | 2-8S LiPo | 5 V at 7 A | $12.99 |
| 15A High-Voltage UBEC | 6-12S LiPo | 5 V at 15 A | $27.99 |
How do you wire a UBEC into your model in 6 steps?
- Unplug the flight pack and remove the propeller before you touch any wiring.
- Connect the UBEC input leads to the flight pack leads.
- Plug the UBEC output lead into the receiver power port.
- Route the wires away from moving parts and hot components.
- Power up the pack and check that the receiver binds and the servos respond.
- Secure the UBEC with foam tape and check it stays cool after a short bench run.
Parts that fit this guide
In-stock parts ship from the New York, USA warehouse in 1-2 business days. Prices below are the live store prices we verified on November 13, 2026.
Switch Mode UBEC 3A BEC (2-6S LiPo) ($10.99)
Switch Mode UBEC 3A BEC at $10.99. It steps 2-6S LiPo down to clean 5 V for a receiver, servos, and flight controller, and it runs cool on 6S.
5A Switch-Mode UBEC, 2-8S LiPo ($10.99)
5A Switch-Mode UBEC at $10.99. It steps 2-8S LiPo down to steady 5 V with headroom for bigger servo loads and hungrier receivers.
7A Switch-Mode UBEC, 2-8S LiPo ($12.99)
7A Switch-Mode UBEC at $12.99. It steps 2-8S LiPo down to 5 V at 7 A for digital servos that spike current draw without browning out the receiver.
15A High-Voltage UBEC, 6-12S LiPo ($27.99)
15A High-Voltage UBEC at $27.99. It steps 6-12S LiPo down to clean 5 V at 15 A for giant-scale electrics and heavy-lift multirotors.
Shop the full range: Power Distribution & BECs at Quality RC Parts. See also: Related guide.
Frequently asked questions
Do I need a UBEC if my ESC already has a BEC?
Many ESCs include a built-in BEC. A separate UBEC helps when your servos draw more current than the built-in BEC can supply, or when your pack voltage exceeds its input range.
Can a UBEC brown out my receiver?
Yes, if current demand exceeds the UBEC rating. Size the UBEC above your peak draw, and the 7A unit covers most digital servo setups.
What voltage does a UBEC output?
The four units in this guide output 5 V. Other UBECs output 6 V or more, so check the listing before you buy.
Does a UBEC work on a 12S pack?
The 15A unit accepts 6-12S input. The 3A, 5A, and 7A units top out at 6S or 8S, so match the input range to your pack.
Sources
- Wikipedia: Battery eliminator circuit
- Pololu: Step-Down Voltage Regulators
- Battery University: Charging Lithium-Ion Batteries (BU-409)
Last updated: November 13, 2026.