TP4056 1A Lithium Battery Charging Module, Micro USB

Charging a single-cell lithium battery safely requires precise control over both the charge voltage and current profile - overcharging a lithium cell is a genuine fire risk, not just an inconvenience - and the TP4056 chip handles that charge profile correctly without needing external control logic, taking a simple USB power input and managing the full charge cycle automatically.

The module charges to a precise 4.2V full-charge voltage with 1.5 percent accuracy, defaulting to 1A charge current though adjustable down to as low as 100mA by changing an onboard resistor - useful for matching the charge rate to a specific battery's safe charging current rather than being locked to one fixed rate regardless of cell size. Input comes through a standard Micro USB connector, letting the module charge directly from any USB power source (a wall adapter, power bank, or computer port) without needing a dedicated charger brick.

Built-in under-voltage lockout and automatic recharge logic handle the charge cycle's edge cases correctly without external intervention, and two status pins (one signaling charge termination, one signaling input voltage presence) let a connected microcontroller monitor charging state if a project needs that visibility. LED indicators give simple visual charge-status feedback even without any connected monitoring circuit.

One important limitation worth knowing: this module has no overcurrent protection built in, meaning a separate protection circuit (either on the battery itself or added externally) is still needed for a genuinely safe complete charging system - the TP4056 handles charge profile correctly but isn't a complete battery protection solution on its own. Builders adding simple single-cell lithium battery charging to a USB-powered project will find the TP4056 a well-proven, extremely common charging module for that basic charging task.