From smartphones and laptops to drones and wearables, lithium-based batteries power most of today’s electronics. But did you know these batteries fall into two main categories: Lithium-Ion (Li-ion) and Lithium-Polymer (Li-Po)? While their names sound similar, their structure, characteristics, and ideal applications are quite different. In this post, we’ll break down these differences and help you understand which battery type powers your devices.     Lithium-Ion: The High-Efficiency Standard Li-ion batteries use liquid electrolytes and typically come in cylindrical or prismatic (rectangular) shapes. They offer high energy density, are cost-effective for mass production, and are widely used in smartphones, laptops, and electric vehicles. Their safety is enhanced when paired with a Battery Management System (BMS). Lithium-Polymer: Lightweight and Flexible Li-Po batteries use gel or solid polymer electrolytes, which means there’s little risk of liquid leakage...

When a battery pack shows 0V across its P+ and P− terminals despite having good cell voltage, it's possible the discharge MOSFET is disabled due to protection lockout. In such cases, temporarily bypassing the MOSFET can help "wake up" the BMS.     1. Why Bypassing the Discharge FET Works The discharge MOSFET controls current flow to external loads. If the BMS controller detects a fault (e.g., undervoltage), it shuts off the gate signal, keeping the FET off and output voltage at 0V. A brief manual connection between P− and B− can restore normal state. P−: BMS output ground controlled by discharge FET B−: Main battery ground connected to cell negative terminal P+: Positive terminal (usually directly connected to B+)     2. Step-by-Step Bypass Test Set your multimeter to DC voltage mode. Measure voltage across P+ and P−. If 0V, proceed to the next step. Using an insulated wire or test lead, briefly connect P− t...