What this product does for you Charge 4.2V lithium-ion / lithium-polymer or 3.6V LiFePO4 packs with a simple selectable mode, so one module works for multiple battery types used in power tools and DIY builds. Delivers a steady 1A constant-current charge while using DC-DC step-down technology to reduce input current to approximately 0.7A. That lowers heat generation and means you typically don’t need extra heat dissipation in normal use. Fits into tight spaces thanks to an ultra-thin profile and an exposed copper backing that makes it easy to attach a heatsink when extra thermal management is needed. Key benefits (why you’ll want it) Versatility: One charger supports the two most common single-cell chemistries (4.2V Li-ion/LiPo and 3.6V LiFePO4) via a simple selection, eliminating the need for separate chargers. Reliable charging: Constant 1A output gives predictable, safe charge rates suitable for many small battery packs and single-cell assemblies. Low heat, simple installation: DC-DC step-down operation reduces input current to ~0.7A, minimizing heat build-up; the exposed copper back allows quick attachment of a heatsink if your installation requires extra cooling. Safety-first operation: Built-in overheating protection automatically reduces charging current to prevent damage, with automatic termination at charge completion and a dual-color LED that indicates charging status in real time. Important specifications (concise) Compatible voltages: 4.2V (Li-ion/LiPo) and 3.6V (LiFePO4) — selectable Charging current: 1A constant current Input behavior: DC-DC step-down reduces input current to ≈0.7A Dimensions: 21.5mm × 14.5mm × 4.2mm (ultra-thin) Thermal: exposed copper backside for heatsink mounting Safety & indicators: overheating protection with automatic current reduction, auto termination, dual-color LED status indicator Typical applications (practical examples) Repairing or building battery packs for cordless power tools where space is limited and you need a compact, selectable charger module. DIY electronics and portable projects using single-cell Li-ion/LiPo or LiFePO4 batteries that require a reliable 1A charging solution without complex thermal management. Small battery maintenance stations or bench chargers where clear charge-state indication and automatic cut-off are required. Why this module stands out Combines chemistry selection, stable 1A charging, and DC-DC efficiency in a very small footprint. Designed to reduce heat by architecture (input reduction to ~0.7A) and to make additional cooling straightforward via the exposed copper backing. Built-in protections and a clear LED status make it practical and safe for repeated use in hobbyist and light professional environments. Use this module when you need a compact, adaptable, and safer single-cell charging solution for common Li-ion/LiPo and LiFePO4 batteries without adding bulky cooling systems.