On/off 

Press and hold the side switch for 0.5 seconds to turn on/off the light.

Output Selection

With the light switched on, single click the switch to cycle through Low→Med→High→Turbo. 

Flash Mode 

With the light switched on, double click the switch to enter Flash mode, single click again to exit flash mode and return to the previously used mode.

Intelligent Memory Circuit 

The bicycle light memorizes the last selected output excluding Flash mode. When turned on again the previously used mode will be recalled.

Battery Specifications 

Warning: *18650 Li-ion batteries are powerful cells designed for commercial applications and must be treated with caution and handled with care. Only use quality batteries with circuit protection will reduce the potential for combustion or explosion; but cell damage or short circuiting are potential risks the user assumes.

Battery Replacement

Unscrew the tail cap and insert the battery following the polarity marks, then screw the cap back on.

Charging 

1. Switch off the light and open the USB cap to reveal the USB Type-C charging port and plug the USB A socket of the charging cable into an electrical outlet, then connect the USB Type-C socket of the charging cable to the light. 
2. The indicator will display red while charging and will turn green when fully charged. 
3. Once charging is completed, be sure to tighten the USB cap to maintain the dustproof and waterproof ability.

Note:

1. The normal charging time of the included Fenix ARB-L18-2600 is approximately 2 hours from depletion to full charging.
2. Recharge a stored light every four months to maintain the optimum performance of the battery.
3. The Low/Med mode is available while charging, but the charging time will be prolonged.

Note: This only works with Fenix ARB-L18 Series 18650 rechargeable Li-ion battery.

Battery Level Indication 

Single click the switch when the light is switched off, the indicator will indicate the battery level and will last for 3 seconds. 

• Green light on: saturated 100% - 85%
• Green light flashes: sufficient 85% - 50%
• Red light on: poor 50% - 25% 
• Red light flashes: critical 25% - 1%

Note: This only works with Fenix ARB-L18 Series 18650 rechargeable Li-ion battery.

Intelligent Overheat Protection            

The light will accumulate a lot of heat when used at relatively high modes for extended periods. When the light reaches a temperature of 60°C or above, the light will automatically step down a few lumens to reduce the temperature. When the temperature drops below 60°C, it will then allow the user to reselect the modes. 

Low-voltage Warning 

When the voltage level drops below the preset level, the bicycle light is programmed to downshift to a lower brightness level until Low mode is reached. When this happens in Low mode, the battery level indicator constantly blinks red to remind you to recharge or replace the battery. 

Note: This only works with Fenix ARB-L18 Series 18650 rechargeable Li-ion battery.

Usage and Maintenance 

• Disassembling the sealed head can cause damage to the light and will void the warranty.
• Fenix recommends using only a high-quality protected battery. 
• If the light will not be used for an extended period, remove the battery for proper storage.
• Unscrew the tail cap or remove the battery to prevent accidental activation during storage or transportation.
• Long-term use can result in O-ring wear. To maintain a proper water seal, replace the ring with an approved spare．
• Periodic cleaning of the battery contacts improves the light's performance as dirty contacts may cause the light to flicker, shine intermittently or even fail to illuminate for the following reasons:
  A: Poor battery level.
  Solution: Recharge or replace the battery.
  B: The contact or contact point of the battery or bicycle light is dirty. 
  Solution: Clean the contact points with a cotton swab soaked in rubbing alcohol.

If the above methods don't work, please contact your authorized distributor.

Warning

• Do place this light out of the reach of children!
• Do NOT shine the light directly into the eyes of anyone!
• Do NOT shine flammable objects at close range, to avoid burning objects or causing danger due to high temperature!
• Do NOT use the light in inappropriate ways such as biting in the mouth, to avoid personal injury or life threats when the light or internal battery fails!
• This light will accumulate a lot of heat while working, resulting in a high temperature of the flashlight shell. Pay attention to safe use to avoid scalding.
• Turn off and lock the light or remove the battery from the light to prevent accidental activation when the light is placed in a closed and flammable environment such as pockets and backpacks!
• The LED of this flashlight is not replaceable; so the whole light should be replaced when the LED reaches the end of its life.

FAQs about Fenix BC21R V3.0 Bicycle Light 

Q1. What kind of LEDs are used in BC21R V3.0? Does Fenix offer to replace LED? 

A: A Luminus SST40 LED with a lifespan of 50,000 hours. 

Fenix does not provide LED replacement services for the time being, and users are not recommended to replace the LEDs independently, which may affect product performance and cause product damage. 

Q2. What is the color temperature of BC21R V3.0? 

A: Around 6000K. 

Q3. What is the working voltage of BC21R V3.0? 

A: Voltage: 3.6V. 

Q4. Is BC21R V3.0 rechargeable? How long is the charging time?  

A: BC21R V3.0 is rechargeable with a USB Type-C charging port and the included 18650 battery. The charging time is about 2 hours. (The indicator will display red while charging and will turn green when fully charged.)  

Note: Once charging is completed, be sure to tighten the light head to maintain the dustproof and waterproof ability. 

Q5. How to prevent accidental activation of the BC21R V3.0? 

A: Unscrew the tail cap or remove the battery to prevent accidental activation during storage or transportation. 

Q6. Why does the BC21R V3.0 downshift to a lower mode after being used for a while and the higher mode cannot be selected? 

A: There are two reasons:  

1. Intelligent Overheat Protection  

The light will accumulate a lot of heat when used at relatively high modes for extended periods. When the light reaches a temperature of 60°C or above, the light will automatically step down a few lumens to reduce the temperature. When the temperature drops below 60°C, it will then allow the user to reselect the modes. 

2. Low-voltage Warning 

When the voltage level drops below the preset level, the bicycle light is programmed to downshift to a lower brightness level until Low output is reached. When this happens in Low output, the battery level indicator constantly blinks red to remind you to recharge or replace the battery.  

Note: This only works with Fenix ARB-L18 series 18650 rechargeable Li-ion battery. 

Q7. Why does the BC21R V3.0 happen to flicker? 

A: Poor battery level. 

Solution: Recharge or replace the battery. 

B: The contact or contact point of the battery or bicycle light is dirty.   

Solution: Clean the contact points with a cotton swab soaked in rubbing alcohol. 

If the above methods don't work, please contact your authorized distributor. 

Q8. What kind of battery can be used in BC21R V3.0? 

A: Fenix ARB-L18 Series Li-ion battery are recommended.  

Other Li-ion batteries are not recommended. As Higher modes fail to light up due to current and voltage limitation, an unmatched battery may cause the light to fail to work normally. 

Q9. What are the optional accessories for BC21R V3.0? 

A: ALD-08, ALD-10. 

Q10. Is the BC21R V3.0 battery port waterproof?

A. The light is waterproof so long as the battery port cover is in place.

Q11.  What should I do if the BC21R V3.0 needs repair? 

A: 1. 15-day replacement: Fenix will replace identical or equal products with documented manufacturing defects within 15 days of purchase. 

2. 5-year free repair: Fenix will repair a light free of charge within 5 years (non-detachable light: 2 years, rechargeable battery and other accessories: 1 year) of purchase if problems develop with normal use. 

3. Lifetime maintenance: If repair is required after 5 years from the date of purchase, Fenix will charge for parts. The total repair fee is dictated by the cost of the replaced materials. 

4. If you need warranty service, fill out the warranty form at https://www.fenixlighting.com/pages/warranty-repairs to start your repair claim.