Fogstar Energy FS4000

Tired of choosing between a massive storage capacity and a high amp discharge when shopping for your high-power mod? The Fogstar Energy FS4000 21700 Battery solves this exact problem instantly. Engineered by one of the UK’s most trusted battery testing powerhouses, this premium 21700 power cell is tailor-made for high-performance and demanding vaping devices. Consequently, you can push your favorite sub-ohm setups to their absolute limits without worrying about sudden voltage drops or mid-day power failure.

🔋 Elite 4000mAh Capacity Paired with a 25A Continuous Output

This heavy-duty cell is designed specifically to keep your advanced setups running at peak power. It treats your kit to a whopping 4000mAh nominal capacity, unlocking staggering longevity that easily outmuscles standard 18650 cells. Furthermore, because it boasts a robust 25A continuous discharge rate, therefore, it safely delivers rapid ramp-up times and thick vapor production across power-hungry dual-battery or single-battery mod configurations.

• High-Drain Dominance: Perfect for sub-ohm, low-resistance builds and variable wattage kits running at high tiers.

• Flat-Top Architecture: Built as a non-protected, flat-top cell engineered to fit flush inside modern regulated vape kits that utilize built-in chipset safeguards.

• Stringent Batch Testing: Part of the premier Fogstar Energy lineup, meaning every batch undergoes meticulous quality control to ensure strict rating safety.

Because it utilizes an advanced Lithium-Ion chemical matrix, you can expect an outstanding typical cycle life of 200 to 500 recharges before noticing any major capacity drop-off. Simply put, it provides a straightforward, highly reliable, and completely hassle-free power solution for modern vapers who refuse to compromise on power or longevity.

⚠️ Critical 21700 Battery Safety Warnings: Lithium-ion cells hold massive amounts of energy and require cautious handling. In addition, always strictly adhere to the following safety protocols:

• Dedicated Smart Charging: Never leave a charging cell unattended. Always recharge your 21700 batteries via a high-quality external smart charger (such as an Xtar bay hub) rather than relying on the vape’s passthrough USB connection.

• Wrap Inspection: Regularly inspect the outer protective wrap and top white insulator circle for small tears, scratches, or nicks. If you spot any damage, repair the wrap immediately or recycle the cell safely.

• Loose Storage Ban: Keep loose batteries away from keys, coins, or other metallic items in your pockets or bags. Always store your spare cells securely inside a dedicated plastic protective battery case.

📦 Accessory Specifications

• Brand: Fogstar Energy (FS4000 Series)

• Battery Size Size: 21700 High-Capacity Configuration

• Nominal Storage Capacity: 4000mAh

• Nominal Working Voltage: 3.6V

• Continuous Discharge Rate: 25A Max Amperage

• Terminal Profile Layout: Flat Top (Non-Protected)

• Ideal Application: Sub-Ohm Coils and High-Drain Regulated Vape Devices

📊 Hardware Dimension Check

🧪 Removable Battery Sizing Guide

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