The USB/DC Lithium Polymer Battery Charger provides flexible charging for single-cell 3.7/4.2 V lithium-ion and lithium-polymer batteries. Connect via the mini-USB port or any standard 2.1 mm DC adapter supplying 5–12 V — the charger automatically selects whichever source has the highest voltage.

Built around the MCP73861 charge controller, the board delivers constant-current/constant-voltage charging with a default rate of approximately 500 mA, adjustable from 100 mA to 1200 mA by soldering in a through-hole resistor. Thermal protection automatically reduces the charge rate if the board gets too warm, even when powered from a 12 V DC source.

Key Features

• Dual Power Input – Charge via mini-USB or 2.1 mm DC jack (5–12 V)
• Automatic Source Selection – Switches to whichever input has the higher voltage
• Adjustable Charge Rate – Default ~500 mA, configurable from 100 mA to 1200 mA
• Thermal Protection – Automatically reduces charge rate to prevent overheating
• Three Indicator LEDs – Green for power, orange for charging, red for error; charging LED blinks when battery is full
• Dual JST Connectors – Keep the battery plugged in while powering your project
• Terminal Block Pads – Solder in 3.5 mm terminal blocks for alternative connections
• Thermistor Support – Standard 10 kΩ thermistor pad (populated with a standard resistor by default)
• Safety Timer – Automatically stops charging after approximately 14 hours

Specifications

• Charge Controller – MCP73861
• Input Voltage – 5–12 V (USB or DC)
• Battery Compatibility – Single-cell 3.7/4.2 V LiPo/LiIon (not for older 3.6/4.1 V cells)
• Charge Rate – 100–1200 mA (default ~500 mA)
• Dimensions – Approximately 44.5 × 40.6 mm

Ideal For

• Portable electronics and wearable projects
• IoT devices requiring rechargeable battery power
• Prototyping with lithium polymer batteries

Package Contents

• 1× USB/DC Lithium Polymer Battery Charger (fully assembled and tested)
• 1× JST cable

Resources

• Schematic (MCP73861)