Why your laptop usually prefers being plugged in 🔌💻 (And what battery chemistry has to do with it.) Most modern laptops use lithium-ion batteries—cells that degrade when they’re exposed to high current, high heat, or deep charge cycles. When you run demanding tasks (coding, 3D modeling, training ML models, gaming) on battery power alone, the system has to pull more current from the cells. Higher current → higher internal resistance heating → faster chemical wear. When you’re plugged in, the power adapter handles most of the load, so the battery doesn’t have to supply those big current spikes. That means fewer high-stress cycles and less heat, two of the biggest contributors to lithium-ion aging. There’s also the state-of-charge factor: Li-ion batteries age fastest when they spend long periods near 100% and warm. Many laptops today counter this with “smart charging” that caps the battery at ~80% when plugged in for long periods—reducing voltage stress on the cathode. So the genera...