Fenix ARB-L21-5000 V.2 is a high-drain 21700 lithium-ion battery with an impressive capacity of 5000 mAh, equipped with an advanced protection system.
Fenix ARB-L21-5000 V.2 Battery - Features
- Rechargeable Li-ion 21700 cell with 5000 mAh capacity; high discharge current (up to 7.5 A);
- stable current capacity; no memory effect - can be recharged at any time;
- long service life: up to 500 charge cycles while retaining about 75% of capacity;
- steel casing - high mechanical resistance and lower risk of short circuit if dropped;
- pressure relief vents to release gas in emergency situations;
- multi-level protection: against over-discharge, overcharging, short circuit, overheating; PTC cathode (overload protection);
- recommended charging: with a 1 A charger (max. 5 A) for a longer service life.
Reliability and performance
The ARB-L21-5000 is currently the highest-capacity power cell for flashlights, ensuring significantly longer runtime and stable current output.
Thanks to its advanced construction and multi-level protection, the manufacturer guarantees up to 500 charge cycles while retaining up to 75% of capacity. This means the cell can be discharged and recharged daily for a period of 1.5 years - a strong indicator of its quality and performance. Because there is no memory effect, Fenix batteries can be charged at any time without any negative impact on their capacity or lifespan.
The steel casing provides high mechanical resistance and reduces the risk of short circuit if dropped or impacted. The battery uses pressure relief vents responsible for releasing gases that could otherwise cause swelling or explosion in the event of an accidental short circuit.
Fenix ARB-L21-5000 V.2 Battery - Advanced Safety Features
The manufacturer has implemented a multi-level safety system that maximizes service life while ensuring the highest level of battery safety.
Safety systems:
- Protection against over-discharge during use
- protection against overcharging during charging
- circuit protection against short circuits
- overheating protection
- PTC-protected cathode (overload protection)
To maximize the battery's service life, it is recommended to use a 1 A charger, not exceeding 5 A. Maximum discharge current is 7.5 A.

