Foursevens 18650


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If you buy cheap batteries...that's exactly what you'll get

WORKS WITH: Prometheus Alpha Lights (and other 18650 lights)

What you get for your money

  • Reliability: Less chance the cell stops working for no apparent reason (it happens) 
  • Consistency: Every battery has similar performance (as opposed to variable) 
  • Safety: Mechanical and electronic safety features (a "protected" cell)
  • Lifetime: Longer total life span because of the characteristics above
We finally made the leap and now have our own custom batteries! As you know, I'm obsessed with quality and these li-ion cells are top of class and are guaranteed to deliver. The base cell is a premium Japanese-made product and integrated with a battery protection PCB. 

Please note: most sellers rate this cell at 3500mAh but in real life they are 3400mAh...and that's how we label them. No hype remember? ;)  

PROTECTION CIRCUIT: These batteries contain a specialized electronic "protection circuit" for user safety. The prevents over charge, over discharge, over voltage, and under voltage conditions. 

RECHARGE EARLY AND OFTEN! Do not run these batteries until they are completely empty (when the light shuts off on its own). Doing so will trip the protection circuit and render the battery inoperable. The Foursevens Flex Charger and Xtar VC2/VC4 chargers are normally able to reactivate a tripped battery; however, this is not best practice and fully draining the battery causes long term damage to the cell.


Size 18650 (18.75mm x 69mm)
Weight 1.8 Oz
Terminal Type "Button Top"


3.7V Nominal (4.2V full charge)
Capacity 3400 mAh
Service Life ~ 500 Cycles
Charge Retention 80% @ 6 Months
Maximum Discharge 7 Amps @ 2C
Electronic Protection Over charge, over discharge, over voltage, under voltage
Where it's Made

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