Fenix BC28R Reference ManualUpdated an hour ago

The Fenix BC28R is a smart head and tail bike light combo. This summary is drawn from the manufacturer's official user manual — see the downloadable PDF reference manual on the product page for complete details.

Warning

Do not look directly at the light sources, stare at the beams for a long time, or shine this product directly into the eyes of anyone.
Do not place this product in the reach of children.
Do not place light heads near flammable objects — high temperatures can cause objects to overheat and become flammable/ignite.
Do not use this product in inappropriate ways such as holding it in your mouth; doing so could cause serious personal injury or death if the lights or internal batteries fail.
This product will accumulate a significant amount of heat while operating, resulting in a high temperature of the light shells. Pay close attention to avoid burns.
Turn off this product or remove the battery to prevent accidental activation when the product is placed in a closed and flammable environment such as pockets and backpacks.
The LEDs of this product are not replaceable; the whole product will need to be replaced when any LED reaches the end of its lifespan.

Overview

Maximum output 2500 lumens, maximum beam distance 180 meters
Equipped with high-quality light sources: 1x Cree XHP50D white LED, 1x red COB
Smart linked-control solution for front and tail lights, efficient and convenient to operate
Front light displays the tail light mode status in real time, making riding safety indications clear at a glance
Uses an anti-glare cut-off facula line design to effectively reduce glare, meeting the needs of safe and courteous riding
Front light is powered by one replaceable ARB-L21-5000 V2.0 battery; tail light features a built-in 400mAh battery
USB Type-C standard charging port
Battery level indication and low-voltage warning
IP66-rated protection and 1.5 meters impact resistance
Size: front light 4.33'' x 1.14'' x 1.57'' / 110 x 29 x 40 mm, tail light 1.38'' x 1.42'' x 1.30'' / 35 x 36 x 33 mm (excluding mounts). Weight: front light 8.47 oz / 240 g, tail light 1.98 oz / 56 g (including mount, battery, and accessories)

Operating Instructions

Front and Tail Light Pairing: by default, press and hold the tail light switch for about 5 seconds; the tail light indicator will flash red and green alternately, indicating it has entered pairing mode. Single click the front light switch — the tail light indicator will turn steady green. Single click the tail light switch again to confirm, and pairing is complete. Once paired, the front light automatically remembers the tail light; the straight-line pairing distance should not exceed 1.5 meters, and pairing mode times out after 60 seconds of no operation.

Front Light On/Off: press and hold the front light switch for 0.5 seconds to turn it on/off.

Front Light Output Selection: with the front light on, single click the switch to cycle through Low → Med → High → Turbo.

Front Light Flash Mode: double click the switch to enter Flash mode; single click again to return to the previously used General mode output. Flash mode does not work when the front light battery is below 10%.

Tail Light On/Off: press and hold the tail light switch for 0.5 seconds to turn it on/off.

Tail Light Output Selection: with the tail light on, single click the tail light switch (or the front light switch) to cycle through Low → Low Slow-flash → Low Fast-flash → High → High Slow-flash. The front light switch indicator simultaneously displays the tail light's current output status.

Standby Mode: with the tail light on, press and hold the front light switch for more than 0.5 seconds to enter standby. Press either switch to wake the tail light and recall the previously used output; with no operation within 1 hour, the tail light automatically turns off.

Intelligent Memory Circuit: both lights memorize the last selected output, excluding Turbo and Flash. When turned on again, the previously used output will be recalled.

Battery Specifications (Front Light)

Fenix ARB-L21-5000 V2.0 (21700, 3.6V): Recommended
Fenix ARB-L21 Series (21700, 3.6V): Usable
Fenix ARB-L18 Series (18650, 3.6V): Banned
Rechargeable Battery (21700, 3.7V): Banned

21700 Li-ion batteries are powerful cells designed for commercial applications and must be treated with caution and handled with care. Using low-quality batteries or mishandling batteries (such as short-circuiting or overheating) could lead to combustion and jeopardize the safety of users and property. Using quality batteries with circuit protection will reduce the potential for combustion or explosion. The tail light battery is non-replaceable.

Battery Replacement (Front Light): insert the included battery compartment key into the slot on the front light's tail battery compartment cover, and turn it counterclockwise to open the cover. Insert the battery with the anode side facing inward, then tighten the cover clockwise. Do not use a sharp tool to pry open the compartment.

Charging

Open the anti-dust cover, and connect the Type-C end of the charging cable to the charging port of the front or tail light. The indicator displays a steady red light while charging and turns steady green when fully charged. All outputs can be used normally while charging. When powered off, the normal charging time is about 3.5 hours for the front light and about 1.5 hours for the tail light. Maximum charging power: front light 15W (5V/3A), tail light 2.5W (5V/0.5A) — use only a certified USB charging adapter that complies with local safety standards. Be sure to close the anti-dust cover firmly once charging is complete.

Battery Level Indication

Each time the product is turned on, the indicator will show the battery level for 3 seconds (works only with a Fenix ARB-L21 series rechargeable battery, and only applies to the front light): green on (saturated, 100–85%), green flashing (sufficient, 85–50%), red on (poor, 50–25%), red flashing (critical, 25–1%).

Technical Parameters (ANSI/PLATO FL1)

Front Light — General and Flash Modes:

Turbo: Output 2500 lumens, Runtime 2 hours 36 minutes*, Distance 180 meters, Intensity 8083 candela
High: Output 1400 lumens, Runtime 7 hours, Distance 127 meters, Intensity 4017 candela
Med: Output 600 lumens, Runtime 12 hours, Distance 82 meters, Intensity 1675 candela
Low: Output 50 lumens, Runtime 52 hours, Distance 23 meters, Intensity 137 candela
Flash: Output 600/50 lumens

Tail Light — Warning Modes (100 meter warning distance for all):

Low: Output 10 lumens, Runtime 6 hours
Low Slow-flash: Output 10 lumens, Runtime 10 hours
Low Fast-flash: Output 10 lumens, Runtime 15 hours
High: Output 20 lumens, Runtime 3 hours 43 minutes
High Slow-flash: Output 20 lumens, Runtime 6 hours 38 minutes

Impact Resistance: 1.5 meters | Waterproof: IP66

Note: Specs measured by Fenix using one Fenix ARB-L21-5000 V2.0 battery (front light) / one built-in 400mAh battery (tail light) at 21±3°C / 50–80% humidity; real-world performance varies. *Turbo output is measured in total runtime including output at reduced levels due to temperature or the built-in protection mechanism.

Intelligent Overheat Protection

The product will accumulate a lot of heat when used at high output levels for extended periods. When it reaches a temperature of 50°C/122°F or above, it will automatically step down a few lumens to reduce the temperature; when the temperature drops below 50°C/122°F, the product will gradually recall the preset output level.

Low-Voltage Warning

When the battery level is low, the battery level indicator will blink red at 3 Hz to remind users to recharge in a timely manner. The product will not turn off automatically, and the indicator will keep blinking until the battery runs out.

Usage and Maintenance

Disassembling the sealed heads can cause damage to the product and will void the warranty.
Fenix recommends using an excellent quality battery.
If the front light will not be used for an extended period, remove the battery, or it could be damaged by electrolyte leakage.
Recharge a stored product every three months to maintain optimum performance of the batteries.
Periodic cleaning of the product and battery contacts improves performance, as dirty contacts may cause flickering, intermittent shining, or failure to illuminate.
If issues persist, contact the distributor.

What's Included

Fenix BC28R front light, BC28R tail light, front light bicycle mount, seatpost mount, mounting strap, ARB-L21-5000 V2.0 battery, battery compartment key, USB Type-C charging cable, spare O-ring, spare bicycle mounting shim, user manual, and warranty card.

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