How wireless charging works

How wireless charging works

Qi and Qi2 chargers move power across a short air gap with two coils: one in the pad or stand, one in the phone. The coils have to overlap. A magnetic ring (MagSafe-compatible or Qi2) holds the phone on the sweet spot so the coils stay aligned.

Cases listed as MagSafe-compatible or Qi2-compatible keep that ring in the right place and are thin enough in the center for the field to pass through. Metal plates, thick wallets, or off-center grips can slow or stop a charge.

15W figures on a charger assume a matching phone, a compatible case, and a power supply that can deliver that rate. Actual wattage follows the phone’s limiter.