Fenix 18650 3500 mAh (L18-3500U) rechargeable battery with its own built-in micro-USB charging port. It can be charged either by connecting a cable to the micro-USB port (e.g., from a computer or mobile phone charger) or in a standard charger. Li-ion rechargeable batteries are characterized by very high capacity, and they do not suffer from memory effect or self-discharge. Li-ion batteries in the 18650 size are the best choice in terms of stored energy relative to the dimensions and weight of the battery.

Fenix battery protection consists of internal safety mechanisms and protective electronics. Added electronic circuits prevent the cell from overcharging, over-discharging, short-circuiting, or drawing excessive current. If the battery electronics detect that limit values have been reached, they safely disconnect the cell.

Internal protection consists of a separator, overheat protection (PTC thermal protection), and a special pressure relief valve. In the event that gas pressure within the cell exceeds a certain limit, the internal separator separates the electrodes inside the battery, thereby de facto interrupting the exothermic reaction, and the pressure relief valve releases the excess gas pressure outside the battery. Thanks to the combination of electronic and mechanical (thermal and pressure) protection, Fenix batteries are among the safest available Li-ion batteries.

In size, the 18650 battery corresponds roughly to two CR123A lithium batteries, which is why it is often used in flashlights as a rechargeable alternative to these primary cells. Check first whether your device supports this cell. This battery is intended, for example, for operation in LED flashlights Fenix E28R V2.0, E30R, Fenix E35 UE (not intended for E35 V3.0 and E35R), PD32R, PD35 V3.0, PD35R ACE, TK11 TAC, TK11R, TK15, TK16 (1000 lm version only), TK25 UV, TK25 IR, TK25 Red, TK25 R&B, TK35R, TK75, FD41, LD30, LD30R, LD35R, and WT25R. Also in LED headlamps Fenix HL55, HL60R, HP12R-T, HP25R (1000 lm version only), HP30R (1750 lm version only), HM60R, HM61R, HM62-T, HM65R, HM65R-T, HM75R, HM75R Topaz, lanterns CL26R, CL30R, and bike lights Fenix BC21R, BC22R, and BC30.

Note: due to the 70 mm length and diameter, it may not fit in some older models - for example Fenix PD31, TK11, TK21, TK30, Zebralight, Solarforce. The battery is also not compatible with Fenix FD65 and Fenix TK47 models.

Parameters of the Fenix 18650 3500 mAh USB battery

• Nominal voltage: 3.6 V
• Capacity: 3500 mAh, tested with 0.2 C discharge current ending at 2.5 V and 25 °C temperature
• Maximum discharge current: 2 C (7 A)
• Maximum charging current: 2 A, charging current of built-in micro-USB input: 0.8 A.
• Dimensions: 18.6 mm (diameter) x 70 mm (length) (+/- 0.5 mm)
• Weight: 50.2 g
• Protection against overcharge, over-discharge, and short circuit (>7 A).
• Lifespan: more than 500 charging cycles
• Recommended operating temperatures: 0-45 °C (charging), -20 to +60 °C (discharging)
• Package contents: one piece of Fenix 18650 3500 mAh USB battery (ARB-L18-3500U).
• USB cable is not included but can be purchased separately.
• Datasheet of the cell used directly from the manufacturer can be downloaded here.

Charging via micro-USB connector

Plug the USB cable into the side micro-USB connector; during charging, the indicator light on the top of the battery glows red. Upon reaching full charge, it glows blue or green.

Recommended chargers

Charger Fenix ARE-A2
Charger Fenix ARE-A4
USB Charger Fenix ARE-D1
USB Charger Fenix ARE-D2
Mini USB Charger MC1
USB Charger Lii-100
Charger Lii-600
Eight-channel USB Charger VC8S
SkyRC MC3000

Warning

• If using an older charger bought roughly before 2014, please verify first whether it can accommodate batteries with a length of 69-70 mm.
• Do not discharge the battery below 2.5 V.
• Do not short-circuit the battery (do not connect the cell poles with a conductor).
• Do not throw the battery into fire or water.
• Never insert the battery into the charger with reverse polarity.
• Observe safety principles when using the battery.
• Use only an adequate charger supporting Li-ion batteries.

Warranty

Two-year warranty.