The HX-4S-F30A is a 4-series (4S) 30A Battery Management System (BMS) circuit board used to monitor, protect, and balance 4-cell lithium-ion or lithium iron phosphate battery packs.
 
Key Specifications
Max Operating Current: 30A continuous discharge current.
Supported Chemistries: 14.8V Lithium-ion (Li-ion) or 12.8V LiFePO4.
Charging Voltage: 16.8V–17V for Li-ion / 14.4V–15V for LiFePO4.
Overcharge Voltage: 4.25V (Li-ion) / 3.75V (LiFePO4).
Over-discharge Voltage: 2.5V (Li-ion) / 2.1V (LiFePO4).
 
Core Protections & Features
Overcharge & Over-discharge: Automatically stops charging or discharging when cell voltages reach unsafe limits.
Short-Circuit Protection: Cuts power instantly if a short circuit occurs in the load.
Cell Balancing: Includes a passive balancing circuit to keep individual cell voltages even.
Common Port Design: Uses the same single terminal port for both charging and discharging.