Vapcell K40 21700 4000mAh 30A/45A Flat Top Rechargeable Battery

The Vapcell K40 is a high-drain 21700 built for lights that pull real current. It delivers a rated 4000mAh with a 30A continuous discharge rating and a 45A maximum (temperature-limited to 80°C), putting it in the same class as the Samsung 40T. If your flashlight's turbo mode sags or steps down early on a high-capacity cell, this is the fix.

• 21700 flat top, unprotected INR lithium-ion, brown wrap
• 4000mAh typical / 3900mAh minimum (0.2C)
• 30A continuous, 45A max discharge (80°C cut-off)
• 3.6V nominal, 4.20V full charge, 2.5V cut-off
• Approx. 10mΩ internal resistance (AC 1kHz)
• Standard charge 2A, quick charge up to 6A
• Approx. 21.1 × 70.6mm, 68g

Independent testing: Battery Mooch's bench test rated the K40 at its full 4000mAh and 30A, calling it "about equal to the Samsung 40T". HKJ (lygte-info.dk) found the two test cells tracked well together and called them "good high current cells with a decent capacity".

Fit check: Flat top and unprotected. Confirm your light accepts a flat-top 21700 (most Convoy, Emisar, Sofirn and Wurkkos 21700 hosts do). Devices that need a button top or a protected cell should look at a different SKU.

What's included: 1 × Vapcell K40 21700 4000mAh 30A/45A Flat Top Rechargeable Battery. Ships from Pennsylvania.

Unprotected lithium-ion cell. Use only in devices with their own protection circuitry, charge with a quality Li-ion charger, never exceed the continuous discharge rating, and keep the wrap and top insulator ring in perfect condition. Not for use in devices that require a button-top or protected cell.