1S 3.7V 3A Li-ion BMS Protection Board

Use this to protect a single lithium cell from over-charge, over-discharge and short circuit — the board sits between the cell and your circuit and disconnects it before damage. Commonly used on 18650-powered sensor nodes, wearable projects and DIY power banks where a bare cell would otherwise have no protection at all. Not suitable for loads above 3A continuous, and not suitable for LiFePO4 cells — the cut-off voltages are wrong for that chemistry and will either cut early or not at all. Key specs: 1 cell, 3.7V nominal / 4.2V full, 3A continuous, over-charge, over-discharge and short-circuit protection. Alternative: step up to the 2S board if your pack is two cells in series — a 1S board cannot balance or protect a series pack.