XZD-M1859-V4 Dual USB 5V Power Bank Charger and Discharge Module – 18650 Lithium

The XZD-M1859-V4 is a compact charge and discharge controller board designed for building portable power banks from 18650 lithium-ion cells. It combines a lithium battery charging circuit and a dual-USB boost output stage on a single PCB, allowing a single 5V Micro-USB input to both recharge the connected cell and, when a load is attached, deliver regulated 5V power to external devices. The board is intended for DIY power bank projects, POS terminal backup power, and portable emergency chargers where a simple, low-component-count solution is preferred.

On the charging side, the module accepts a 5V/1A Micro-USB input and charges the battery with a constant current of approximately 1A (with a tolerance of about ±0.1A) once the battery voltage exceeds 3.1V. The charge termination is voltage-limited: the float voltage is set to 4.2V, and the saturation condition is reached above 4.15V, which is the standard single-cell Li-ion charging profile. On the discharge side, the XZD-M1859-V4 power bank module delivers a USB output voltage in the 5.0V to 5.3V range, with two USB ports rated for 1A and 2.1A loads respectively. The average discharge efficiency is stated as greater than 80%. The board includes four LEDs that indicate the battery voltage level, so the user can estimate remaining capacity without an external meter. No push-button is required for output activation; the module automatically enables the USB output when a device is connected and adjusts the charging current to the connected device. The board is compatible with single 18650 cells or multiple cells connected in parallel, and it is not intended for series battery configurations.