Features: The 4s lithiums Battery Boost Charging Board efficiently charges four series batteries with builts in boost circuitry and integrated overcharge/short circuits protections for safe power management. Features double LED indicators ( for charging status, OK for full charge) and converts DC3-5V input to 16.8V output while preventing overcurrent/over discharge through intelligent battery protections circuits. -Ideal for electronics enthusiasts, DIY maker, and engineers requiring reliable multicell lithiums battery charging solution in customs power systems. Perfect for solar energy storage setups, drones battery pack, portability power stations, and industrial equipment requiring stable 4s battery maintenance. Engineered with professional materials, this compactly charging module ensures optimals thermals performances and durability for extended operation in embedde electronics projects. Specifications: Component:Plastic Size:Approx.39x18x6.3mm/1.5x0.7x0.2inch Option Type:1A,2A,4A; Input voltages: DC3-6V(Recommend DC3.7V 5V) Input current: 1A(1A Version);2A(2A Version);4A(4A Version) Charging voltages :16.8V Suitable for MP3 Players, MP4 Players Digital Cameras Game Players Notebook lithiums Battery 18650 Mobile phone Solar charging audios equipment Portable Devices POS , Electric Fan TYPE C charging equipment Package Includes: 1pc Steps up Charging Module note: Please allow 1-10mm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual item color.