Glossary:BMS
A BMS or Battery Management System is a circuit designed to control the charging and discharging of a battery, most usually consisting of multiple lithium cells in a battery pack for a laptop, power tool or electric vehicle. Without it, due to the inevitable variation between cells, some cells might be over-charged with potentially dangerous consequences before others have received their full charge, and some might be over-discharged causing permanent damage while others have charge remaining.