Rechargeable 18650 Li-ion Battery Pack 3.7V 1200mAh ×4 True Capacity Lithium Battery Flat Top Cells for Arduino Robotics IoT Modules LED Systems DIY Electronics Power Supply Energy Storage Flashlight Power Bank Compatible Stable Output UN38.3 IEC62133 Certified Long Cycle Safe Lithium Battery (4 Pack)

This rechargeable lithium battery pack is designed to provide a stable 3.7V output using four individual 18650 lithium ion cells, each rated at a true 1200mAh capacity. The pack configuration ensures consistent voltage delivery, balanced discharge behavior, and reliable energy output for electronic systems that require stable and predictable power performance. This structure makes it suitable for integration into Arduino-based robotics, IoT modules, embedded systems, LED lighting setups, and various DIY electronic applications. The use of flat top lithium cells allows better compatibility with battery holders, power modules, and custom battery pack assemblies where uniform contact surfaces and consistent alignment are required. Compared with button top configurations, flat top batteries are more suitable for series and parallel arrangements, ensuring efficient current transfer and reduced contact resistance. This makes them ideal for robotics platforms, microcontroller development boards, smart control systems, and energy storage modules. Each lithium ion cell is manufactured with controlled internal resistance and stable electrochemical performance, allowing consistent discharge curves and predictable voltage behavior during operation. This ensures that connected devices such as sensors, controllers, and embedded circuits can operate reliably without sudden voltage drops or instability. The battery pack supports repeated charge cycles and is suitable for applications requiring continuous or intermittent power supply. The battery pack complies with international transportation and safety standards including UN38.3 and IEC62133. These certifications confirm that the product has undergone required testing for transport safety, electrical stability, and operational reliability. Each cell is marked with voltage, polarity, and identification information to support safe handling, installation, and maintenance. This rechargeable lithium battery pack is suitable for engineers, developers, educators, and DIY users who require a stable and rechargeable power source for robotics systems, IoT development, STEM education kits, and electronic experiments. It can be used in power banks, LED systems, automation setups, and portable electronic devices where consistent voltage output and rechargeable performance are essential.