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Fenix BC21R USB Rechargeable Bike Light - DISCONTINUED

$96.00 $74.95

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Max Lumens:


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Product Overview

This rechargeable bike light is designed for both mountain biking and urban settings. For the commuter, the BC21R features two side red lights and a flashing mode for additional rider safety. Its quick release mount makes it easy to detach the light, ensuring the light won’t be stolen. Mountain bikers will love the light’s dual beam system for up-close and extended visibility.


Max Lumens: 880
Max Beam Distance: 410 feet (125 meters)
Max Runtime: 15 hours 50 min.
Lighting Modes: 4 brightness levels, and flashing
Bulb Type: Cree XM-L2 T6 neutral white LED
Size: Length: 4.4” (113mm) Width: 1.6” (40.5mm) Height: 1.7” (42mm)
Weight: 3.2 oz. (91g) excluding battery and bike mount
Battery: 18650 3.6V/2300mAh rechargeable battery with Micro-USB charging
Included: Bike mount, mounting shim, mounting strap, spare O-ring, 18650 3.6V/2300mAh battery, USB charging cable
Warranty: Limited Lifetime Guarantee from Fenix Lighting USA

More Information

  • Uses one Cree XM-L2 T6 neutral white LED with better color rendition
  • Powered by one 18650 rechargeable Li-ion battery or two CR123A Lithium batteries
  • Optimized Dual Distance Beam System
  • Micro USB direct charging
  • Built-in over-charge, over-discharge protection
  • Battery Level Indication
  • Low power warning reminds when battery replacement needed
  • Over-heat protection to avoid high temperature of the surface
  • New-type quick-release bike mount for easy and secure adjustment of the light direction
  • Four brightness levels and one flashing mode
  • Digitally regulated output maintains constant brightness
  • Made of aluminum alloy with excellent heat dissipation design
  • Waterproof to IPX-6 standard
  1. The Flash mode will flash at 380 lumens and 100 lumens alternately.
  2. The bike light is equipped with red side lights, it will be activated simultaneously by default. This side red light will be constant-on when the main light is on and flashing red when the main light flashes.
  3. The above-mentioned parameters (lab tested by Fenix using one Fenix ARB-L2-2300 18650 rechargeable Li-ion battery) are approximate and may vary between the bike lights, batteries and environments.
*The runtime of the Turbo brightness level is the accumulated time. The runtime can be longer when uses 18650 battery of larger capacity.  
Fenix BC21R USB Rechargeable Bike Light - DISCONTINUED specs chart


Press and hold the light button for 0.5 seconds to turn ON/OFF the light. 


Output Selection 

With the light on, click the light button to cycle through Low→Mid→High→Turbo→Flash. 



  1. As with any performance light, the bike light builds up heat when it runs for an extended period. Intelligent circuitry in the bike light downshifts the light to lower brightness level to guard against overheating.
  2. The bike light retains the last-used brightness level.
  3. When the battery power level is critical, higher brightness levels can not be activated, and the bike light is programmed to cycle through lower brightness levels.

Battery Level Indicator 

With the light off, single-click the light button, the side light will indicate the battery power level conditions, and then go out after 5 seconds. 

  1. Side light constant-on (sufficient power level): 60%-100%
  2. Side light slow flashing (low power level): 20%-60%
  3. Side light quick flashing (critical power level): 1%-20%

Low Power Warning and Intelligent Output Downshift 

Low Power Warning: With the light on, when the battery level is lower than 20%, the light button will blink red constantly, to remind you to downshift to a lower brightness level to extend runtime or recharge the bike light. 


Intelligent Output Downshift: If non-stop use is needed, the light will downshift to a lower output level to extend runtime. When it downshifts to the flashing mode, the bike light will go out soon. Please stop riding and replace the battery or the bike light.



Operation Points: Remove the anti-dust plug at the bottom of the bike light to reveal the charging port, and plug the Micro USB end of the USB cable into the light’s charging port, then connect the other end of the USB cable to a USB power adaptor. 


Charging Indicator: The indicator light in the bike light blinks red to indicate the charging process has begun. The indicator light turns solid green when the battery is fully charged. 



  1. Turning on the bike light under charging state is not recommended by Fenix. But it will be okay if under emergency situations, the bike light can light up at Low and Mid output.
  2. Once charging is completed, disconnect the USB cable from the light and be sure to secure the anti-dust plug cover.
  3. Fenix recommends using a power adaptor with output over 5V 1.5A. It takes about 4 hours to fully charge the bike light.
  4. The bike light can be connected to the USB cables for digital products such as mobile phones with standard Micro-USB charging port.

No FAQs available.

Customer Reviews

Based on 13 reviews
Michael McKinney

This was bought as a backup return home at night light. I've only used it a few times. My impressions are, great build quality. The light is excellent build quality and has a great light beam for my needs. I've not had any issues with the mount moving, then again it is not used mountain biking. It's seemed to hold a charge long enough for me to use it 4-5 times. I don't use it on Blaze setting, I think it's the middle setting.

The folks at Fenix Lighting are top notch. Colt helped me out with an issue on my E12 flashlight and reached out to some people to help me. Props to everyone there.

Don't forget to remove the small dark thin plastic disk that is on the battery or it won't work. I think this was the problem with some of the peoples complaint about it not working.

David Hoffman

This light is quality, and a great value for the money. I purchased it for a 400-mile bikepacking race and used it to ride technical singletrack and descend on fast gravel roads. It met every expectation. Being able to choose between charging while I ride (from a battery bank) or swap to a fresh battery was the main reason I chose this light. Some reviews say the mounting strap is flimsy. I beg to differ, as my rigid mountain bike on rocky descents threw everything it could at the light and it didn't budge.

Joerg Jaeger

The best light i bought so far. Great plus, the removable rechargeable battery.

John Roadie

There's nothing to fault with this light, it ticks all the boxes (price, quality, performance, features).
I especially wanted a light with a replaceable battery for unlimited runtime. Luckily Fenix came to the rescue with the awesome BC21R!
Contrary to many who have written here, in my experience the mount does not move over bumpy roads and the ladder strap design is easy, lightweight and universal.
I can think of just one improvement, a +/- button would be much better than having to cycle through the levels via a single button - please all bike light manufacturers take note there's an opportunity here!

Artec Durham

A great light. Highly versatile and the ability to change out batteries during a ride is why I purchased this light. Beam pattern and runtime are exceptional. I wish that the handlebar mount was a little more sturdy for trail riding.

Jennifer Hanson

Love it

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