FogStar Energy 21700 4000mah

The Fogstar Energy FS4000 21700 Battery is engineered for enthusiasts seeking exceptional performance and dependability. With a substantial capacity of 4000mAh and a continuous discharge rate of 25A, this rechargeable battery is perfectly suited for high-performance and advanced vaping devices.

Constructed with an emphasis on safety and longevity, the FS4000 21700 features a flat-top, non-protected design, making it suitable for regulated devices that incorporate built-in safety mechanisms, such as vape kits. This ensures it can deliver peak performance without any compromises. It is essential to confirm compatibility with your device prior to use.

Fogstar’s reputable Energy series, the FS4000 undergoes rigorous testing to adhere to stringent quality standards. For safe operation, it is recommended to charge the battery with a dedicated Lithium-Ion charger, routinely check wraps and insulators for any signs of damage, and promptly replace any batteries that show signs of compromise.

Additional Information

Lithium-Ion cells should be charged on a dedicated charger rated specifically for Lithium-Ion cells. Our selection can be found here.
Never leave a battery unattended whilst charging.
Keep away from animals and children.
Wraps and insulators should be periodically inspected for tears or damage. If a battery has a damaged wrap, it should be repaired or disposed of immediately. Wraps and insulators can be found here
If you are re-selling these cells, it is your duty to pass these warnings onto your customers.
Batteries usually have a cycle life of between 200-500 cycles (varies with manufacturer) before noticeable capacity drop off. Batteries should be recycled at this time.
Do not crush, incinerate or modify.
Only use within manufacturers specification.