3.7 V Dual 2-Cell Lithium Battery Charger
🔋 3.7V Dual 2-Cell Lithium Battery Charger Module – TP4056 Based
📝 Overview
This 3.7V 2-cell Lithium Battery Charger Module is designed to safely charge two 3.7V Li-ion or Li-Po cells (such as 18650 batteries) simultaneously. It features independent charging channels, onboard protection circuitry, and micro USB or Type-C input, making it ideal for DIY power banks, portable devices, and battery-powered projects.
⚠️ Note: This charger is for charging two individual cells in parallel, not in series (7.4V systems). For series charging, use a dedicated 2S BMS or balance charger.
⚙️ Key Features
Supports 2 × 3.7V Li-ion/LiPo cells
Overcharge, over-discharge & short circuit protection
Charging current: 1A per channel (typical, varies with module)
Red LED = Charging, Blue/Green LED = Fully charged
Compact size for integration in portable designs
Available with micro USB, Type-C, or DC input
📦 Technical Specifications
| Parameter | Value |
|---|---|
| Input Voltage | 5V DC (via USB or header) |
| Output Voltage | 4.2V max per cell |
| Charging Current | ~1A per cell (adjustable if onboard resistor present) |
| Battery Compatibility | 3.7V Li-ion / Li-Po cells |
| Number of Cells | 2 (parallel charging) |
| Charging Indicator | LED status per cell |
| Protection Circuit | Yes (depending on model) |
| Dimensions | ~25mm × 20mm (varies) |
🛠️ Usage Instructions
Connect USB 5V to input port (Micro USB, Type-C, or IN+/-)
Connect each 3.7V cell to B+/B− terminals
LEDs will indicate charge status per channel
Disconnect batteries after full charge for safety
🎯 Applications
DIY power banks
Battery backup systems
ESP32, Arduino, and IoT battery supply
Flashlights, wearable gadgets, and robotics
Prototyping and testing Li-ion cells