@dk.electronic1: Explanation of the 3S Battery Pack with BMS Protection Board This image shows a 3S lithium-ion battery pack using three 18650 cells and a 3S 40A BMS (Battery Management System). It is designed to protect the batteries during charging and discharging. 1. Battery Configuration The circuit uses three 18650 lithium-ion cells connected in series. Number of batteries: 3 Nominal voltage: 3.7V per cell Total nominal voltage: 11.1V Fully charged voltage: 12.6V Recommended battery type: Compatible 3.6V/3.7V lithium-ion cells. When three cells are connected in series, their voltages add together. Calculation: 3.7V + 3.7V + 3.7V = 11.1V At full charge: 4.2V × 3 = 12.6V 2. BMS Protection Board The green PCB is a 3S 40A BMS protection board. It helps protect the battery pack from: Overcharging Over-discharging Overcurrent Short circuits, if supported by the specific board The actual protection functions and current limits depend on the board's design. 3. Battery Connection Points The board has four battery connection terminals. Terminal Function 0V / B− Battery pack negative 4.2V / B1 Connection to the first cell's positive terminal 8.4V / B2 Connection to the second cell's positive terminal 12.6V / B+ Battery pack positive These voltage labels represent the expected cumulative voltage levels relative to battery negative when the cells are at the appropriate charge levels. 4. Output and Charging Terminals On the right side of the board, two terminals are marked: Output+/Charging+: Positive output and charger connection. Output−/Charging−: Negative output and charger connection. This arrangement is commonly used with a common-port BMS. Confirm the exact terminal designations on the actual board before wiring. 5. Charging the Battery Pack Use a 12.6V CC/CV lithium-ion charger designed for a 3S battery pack. The BMS provides protection, but it does not replace a suitable charger. 6. Important Safety Precautions Use three compatible lithium-ion cells with matching specifications and similar charge levels. Never connect a 12.6V charger to a single 3.7V cell. Check the BMS terminal labels carefully before connecting the batteries. Avoid short circuits, as lithium-ion cells can deliver very high currents. Do not assume the board can continuously handle 40A without verifying its specifications and cooling requirements. In summary: This is a 3S lithium-ion battery pack with a 3S 40A BMS. It provides approximately 11.1V nominal and 12.6V when fully charged, making it suitable for compatible 12V battery-powered equipment.#francetiktok #basicelectronics #foryou #electronic #electronicseducation
