Fenix · Battery · 18650 Li-Ion
Fenix ARB-L18-3400
18650 Li-Ion Battery – 3,400 mAh
Reliable power for demanding flashlights – with built-in protection circuit.
Reliable power source for Fenix high-performance flashlights
The Fenix ARB-L18-3400 is a rechargeable 18650 Li-Ion battery with a capacity of 3,400 mAh and a nominal voltage of 3.6 V. Designed as the original power supply for numerous Fenix flashlights, the ARB-L18-3400 combines high energy density with a built-in protection circuit board (PCB) that guards against overcharging, deep discharge and short circuits. Whether on a night hike, during standby duty or while camping – this battery delivers the energy you need for extended runtimes and reliable illumination.
Safety · PCB protection
Built-in protection circuit – maximum safety with every use
The ARB-L18-3400 features a built-in PCB protection circuit that monitors three critical operating conditions. The overcharge protection prevents cell damage when connected to a charger. The deep discharge protection shuts down the battery before the voltage drops to a harmful threshold. And the short-circuit protection cuts the current immediately in the event of a fault. This triple safety net makes the ARB-L18-3400 one of the safest 18650 batteries on the market.
3,400 mAh – maximum runtime for your flashlight
With a capacity of 3,400 mAh at 3.6 V nominal voltage (12.24 Wh), the ARB-L18-3400 ranks among the highest-capacity 18650 batteries in the Fenix range. The high energy density provides noticeably longer runtimes compared to standard 18650 cells with 2,600 mAh. Over more than 500 charge cycles, the battery maintains stable capacity – a long-lasting alternative to disposable batteries.
Broad compatibility – fits numerous Fenix flashlights
The ARB-L18-3400 is compatible with all Fenix flashlights and devices that use an 18650 cell with protection circuitry. This includes models such as the Fenix PD35, PD36R, TK16, UC35 V2.0, LD30, E28R and many more. Thanks to the standardised 18650 form factor (69 mm length, 18.6 mm diameter), the battery also fits compatible chargers such as the Fenix ARE-A2 or ARE-D2.
Built for outdoor use – from −20 to 60 °C
The ARB-L18-3400 has been engineered for demanding conditions. The operating temperature range of −20 °C to 60 °C allows use in sub-zero winter conditions as well as hot summer environments. The robust steel casing and high-quality cell guarantee reliable power delivery even under mechanical stress. At just 48 g, the battery adds virtually no weight as a spare in your pack.
Key features – Fenix ARB-L18-3400
- 🔋 3,400 mAh capacity – maximum runtime for 18650-compatible Fenix flashlights
- ⚡ 3.6 V nominal voltage / 12.24 Wh energy – designed for high-performance applications
- 🛡️ Built-in PCB protection circuit – overcharge, deep discharge and short circuit are automatically prevented
- 🔄 Over 500 charge cycles – durable and economical compared to disposable batteries
- 🌡️ Operating temperature −20 to 60 °C – ready for extreme conditions
- 📏 18650 standard dimensions: 69 mm × 18.6 mm – compatible with Fenix PD35, TK16, UC35 V2.0 and more
- ⚖️ Only 48 g – light enough as a spare battery in your gear
- ✅ Fenix original accessory – optimally matched to Fenix devices
- 🌿 Rechargeable – eco-friendly alternative to disposable CR123A batteries
- 🏅 1-year Fenix manufacturer warranty on the battery
Who is the Fenix ARB-L18-3400 for?
The ARB-L18-3400 is the ideal power source for all owners of Fenix 18650 flashlights who expect maximum runtime and reliable performance. Whether as original equipment, a replacement or a backup – this battery is suited for outdoor enthusiasts, security personnel, hunters and anyone who relies on dependable illumination.
Technical Specifications – Fenix ARB-L18-3400
| Model | Fenix ARB-L18-3400 |
|---|---|
| Type | Rechargeable 18650 Li-Ion battery |
| Capacity | 3,400 mAh |
| Nominal voltage | 3.6 V |
| Energy content | 12.24 Wh |
| Protection circuit | Built-in PCB – overcharge, deep discharge, short circuit |
| Charge cycles | over 500 |
| Operating temperature | −20 to 60 °C |
| Dimensions | 69 × 18.6 mm (L × Ø) |
| Weight | 48 g |
| Compatibility | Fenix 18650 flashlights (PD35, PD36R, TK16, UC35 V2.0, LD30, E28R and more) |
| Warranty | 1-year manufacturer warranty + 2-year Swiss statutory warranty |
Package Contents – Fenix ARB-L18-3400
- 🔋 Fenix ARB-L18-3400 18650 Li-Ion battery
- 📄 User manual
Frequently Asked Questions – Fenix ARB-L18-3400
What is the capacity of the Fenix ARB-L18-3400?
The Fenix ARB-L18-3400 has a capacity of 3,400 mAh at a nominal voltage of 3.6 V, equating to an energy content of 12.24 Wh. This makes it one of the highest-capacity 18650 batteries in the Fenix range.
What protection mechanisms are built in?
The ARB-L18-3400 features a built-in PCB protection circuit that guards against overcharging, deep discharge and short circuits. This triple safety function prevents cell damage and ensures safe operation.
How many charge cycles does the battery support?
The ARB-L18-3400 is rated for over 500 charge cycles. Throughout these cycles the cell maintains stable capacity before performance noticeably declines.
Which Fenix flashlights is the battery compatible with?
The ARB-L18-3400 fits all Fenix flashlights and devices that accept an 18650 cell with protection circuitry – including the Fenix PD35, PD36R, TK16, UC35 V2.0, LD30 and E28R.
Can the battery be used in extreme temperatures?
Yes. The operating temperature range extends from −20 °C to 60 °C. At very low temperatures the delivered capacity may temporarily decrease, but the cell will not be damaged.
What is the difference between the ARB-L18-3400 and the ARB-L18-3400U?
The ARB-L18-3400 is charged using an external charger. The ARB-L18-3400U additionally features a built-in Micro-USB charging port and can be charged directly without a separate charger.
Which charger is recommended for the ARB-L18-3400?
Fenix recommends its own ARE-A2 or ARE-D2 chargers, which are optimised for 18650 cells. In principle, any quality Li-Ion charger with 18650 compatibility can be used.
What warranty applies to the Fenix ARB-L18-3400?
Fenix provides a 1-year manufacturer warranty on the ARB-L18-3400. In addition, the statutory 2-year warranty under Swiss consumer law applies.
