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Weltool UB21-50 5000mAh Rechargeable lithium-ion battery

$26.50 USD
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The Weltool UB21-50 battery – a revolutionary power source that combines cutting-edge technology with exceptional reliability to deliver unparalleled performance in a wide range of applications. Whether you're powering high-drain devices or relying on dependable backup power, the UB21-50 battery sets a new standard for lithium-ion battery performance.

Innovative Design for Enhanced Safety and Durability

Unlike traditional Li-ion batteries with nickel plate connections for negative protection circuits, the Weltool UB21-50 features built-in protection circuitry integrated into the battery positive, enhancing safety and durability. The steel shell, riveted and integrated with the battery core, effectively prevents short circuits caused by collisions or wear, without increasing the battery's diameter.

The Type-C USB charging interface, located within the positive protection circuit, offers versatile charging options. Simply connect the battery to a 5V adapter or high-current USB port on a computer or mobile power source using a USB charging cable. Additionally, the battery can be charged using a compatible charger. The charging indicator on the battery provides real-time feedback on the charging status, ensuring hassle-free operation.

High Performance for Demanding Applications

The UB21-50 battery is powered by selected 21700 Li-ion battery cells with low internal resistance, high capacity, and a large discharge current, making it ideal for powering high-drain devices such as flashlights, headlamps, and more. With a continuous discharge current of 14.5A (at 10-25°C), the UB21-50 battery delivers reliable power output even in demanding conditions.

Triple overheat protection mechanisms, including pressure safety valve protection, diaphragm micro-hole protection, and PTC cathode blocking protection, ensure optimal safety during operation. The battery's positive protection circuit provides additional safeguards against overheating, overcharging, over-discharging, and short circuits, enhancing user confidence and peace of mind.

Versatile Compatibility and Robust Construction

The UB21-50 battery is designed for compatibility with a wide range of devices, including flashlights and other electronic devices that require reliable power sources. Its raised positive cap ensures a secure connection with flashlight contacts, while the robust surface labeling process enhances durability and safety.

With a capacity of 5000mAh and dimensions of 21.4mm (diameter) and 76mm (length), the UB21-50 battery strikes the perfect balance between performance and portability. Weighing just 73g, it is lightweight and compact, making it easy to carry and transport wherever your adventures take you.

In conclusion, the Weltool UB21-50 5000mAh Rechargeable Lithium-ion Battery represents the pinnacle of battery technology, offering unmatched performance, safety, and reliability for a wide range of applications. Whether you're a professional user in need of dependable power sources or an outdoor enthusiast seeking reliable backup power, the UB21-50 battery is your trusted companion for all your power needs. Invest in the Weltool UB21-50 battery and experience the difference it can make in your daily life.


  • Model: UB21-50
  • Capacity: 5000mAh
  • Internal resistance: ≤50mΩ
  • Voltage: 3.6V
  • Continuous discharge current : 14.5A(10-25 ℃)
  • Charging current: 2A (Type-C USB interface charging current), 3.4A (Max. charger charging current)
  • Overcharge protection voltage: 4.25±0.05V
  • Over-discharge protection voltage: 2.5±0.1V
  • Cycle charge and discharge times: 300 times, the battery has 80% capacity
  • Charging indicator: red light (charging), blue light (charged)
  • Charging temperature: 0-45 ℃
  • Discharge temperature: -20-55℃
  • Storage temperature: -20-55℃
  • Dimensions: 21.4±0.2 mm (diameter), 76±0.2 mm (length)
  • Weight: 73±0.5g

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