Understanding the thermal ceiling in portable power

Wireless charging performance is limited less by power delivery than by the physics of heat, and solving it requires rethinking the hardware. Plug a phone into a modern charger and the first 10 minutes are impressive. The next 20 are not. This is not a defect. It's the connected device protecting itself. As temperature rises during charging, a smartphone's battery management system reduces the current it will accept, because heat accelerates the chemical degradation that permanently reduces battery capacity.