Mountain Equipment Company

Gemini 4000mAh Two Cell Battery


Colour: Black

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Rocksolid guarantee

Shop with confidence. If it’s not working out, you can return it (consumables, electronics, undergarments and swimwear excluded).
Really. If it's not up to snuff after you use it (a couple times) you can still bring it back. It lasts longer than 30 days, but not forever. We'll be fair about it.


Keep your Gemini Duo, Titan, or other compatible lights running on long night rides, or just have a back-up. Based on the 21700 platform, this rechargeable battery has an excellent power-to-weight ratio, because every gram counts. It can pull double-duty as a powerbank, to top up you phone and gadgets.

  • 2, 21700 cells
  • 30Wh 7.4V 4000mAh capacity
  • Input ports: DC 8.4V, USB-C 5V, output: DC 6-8.2V (5.5x2.1mm round connector), USB-C 5V
  • LED power gauge shows status, both charging and discharging
  • Tough polycarbonate shell with rubber bumpers to protect your frame

Tech specs

Ideal for
  • Mountain biking
  • Cycle commuting
  • Cycle touring and bikepacking
Product sustainability
  • Rechargeable batteries
Made inChina


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