The Qi Standard

The Qi standard ensures certified chargers and devices can work together. It defines coil geometry, communication protocols, and safety limits. When you place your phone on a Qi pad, the devices negotiate power levels using low-energy signals before full charging begins.

Power levels have climbed steadily. Early Qi delivered 5 watts. Qi2 brought magnetic alignment and interoperable 15-watt phone charging, and the newer Qi2 25W specification raises certified phone-class charging to 25 watts when both charger and device support it. Some proprietary systems push beyond 50 watts by adding cooling and tighter coil alignment. The trade-off is always the same: more power means more heat, and more heat means more engineering to manage it.