Overview
The LiitoKala King4000 is a 3.7V 18650 Li-ion rechargeable battery designed for high-capacity and stable performance. With up to 4000mAh nominal capacity and ≤25mΩ internal resistance, it provides long runtime and efficient energy delivery for various high-drain devices.
Main Features
- 4000mAh large capacity for extended operation and power stability
- Low internal resistance (≤25mΩ) for efficient discharge and reduced heat
- Rechargeable up to 1000 cycles, ensuring long-term reliability
- Explosion-proof safety valve and durable metal casing for maximum protection
- Supports custom configurations: flat-top, button-top, nickel strip, or PCB versions
- Wide working voltage range from 2.75V to 4.2V
- Certified quality and consistent performance under heavy load
Technical Specifications
| Parameter | Value |
|---|---|
| Brand | LiitoKala |
| Model | King4000 |
| Type | Li-ion 18650 Rechargeable Cell |
| Rated Voltage | 3.7V |
| Capacity | 3800–4000mAh |
| Charge Voltage | 4.2V |
| Working Voltage | 2.75–4.2V |
| Internal Resistance | ≤25mΩ |
| Recharge Cycles | Up to 1000 |
| Size | 18.5 × 65.5mm |
| Weight | 48g ±1g |
| Protected | Optional (custom PCB) |
| Shell | Explosion-proof metal casing |
| Operating Temperature | -20°C to +60°C |
| Packaging | 400pcs/box (42.5×22×16cm) |
Applications
Primary Uses:
The King4000 provides reliable 3.7V power for Bluetooth speakers, POS systems, dash cameras, and massagers, maintaining steady output over long discharge periods.
Extended Benefits:
Ideal for beauty instruments, LED flashlights, and portable devices requiring high energy density and consistent voltage under heavy load.
Compatibility / Upgrade:
Compatible with most 18650 devices and LiitoKala smart chargers. Available in flat-top or button-top versions to suit diverse electronic equipment and battery pack assembly needs.
Product FAQ
What is the actual capacity range of the King4000?
The typical capacity ranges between 3800–4000mAh, depending on discharge current and conditions.
Is this battery protected or unprotected?
The standard version is unprotected, but PCB-protected versions are available for customized applications.
What devices can use this battery?
It is suitable for flashlights, speakers, recorders, massagers, and other 3.7V Li-ion compatible devices.
Are there safety features built in?
Yes, the battery includes an explosion-proof valve and low internal resistance design to ensure safe operation.





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