If you’ve taken the time to shop for a wireless charger, then you’ve probably bumped into the term “Qi-Certified.” But what the heck is Qi, and why should you use a Qi-Certified wireless charger?
Qi Is Just a Wireless Charging Standard
Qi (pronounced “chee”) is a standard for wireless energy transmission. It’s a format that’s maintained by the Wireless Power Consortium (WPC), and it aims to standardize wireless charging across all devices in the same way that the USB or Bluetooth standards have standardized data transmission across all devices.
But why does wireless charging need to be standardized?
Well, without a standard like Qi, wireless charging would be a serious pain in the ass. Imagine if every smartphone used its own unique cable instead of Micro-USB, USB-C, or Lightning. Without the Qi standard, that’s the nonsense that you’d have to deal with.
We say “basically” because, technically speaking, it’s possible for unstandardized wireless chargers to work with unstandardized phones. But co-mingling power standards with unsupported devices is both ineffective and dangerous.
The Qi Standard Keeps Things Safe and Easy
Wireless chargers rely on magnetic induction or magnetic resonance to transmit energy (Qi uses both). It’s sort of like the magnetic field that surrounds the Earth. Your phone contains a coil that converts this magnetic energy into electrical energy, which then charges the battery. Simple, right?
That’s why it’s technically possible for unstandardized wireless chargers to work unstandardized receivers in phones. But let’s imagine a world without wireless charging standards. You’d run into three big problems:
- Overloading Phones: Smartphones have built-in voltage limiters that prevent wired overcharging. But wireless charging relies on a coil, like a coil on an electric stovetop. Without a wireless charging standard, a high powered wireless charger (say, 25 watts) could damage a low-powered wireless phone’s coil (which may have a limited range of 0-5 watts) along with its battery and other internals.
- Overheating: This is already a common problem for high-voltage (or cheap) wireless chargers. Without proper power management or ventilation, heat will build up and damage your phone. Enough heat can cause a battery to deteriorate, which can also lead to fires.
- Heat Transfer to Nearby Objects: Without built-in Foreign Object Detection (FOD), a wireless charger may be inclined to push magnetic energy at things that aren’t phones, like pieces of metal or nearby objects. This can cause overheating, fires, or burns.
The Qi wireless charging standard effectively ensures that we’ll never run into these problems. When a phone or charger is Qi-Certified, it’s tested by the Wireless Power Consortium for safety, effectiveness, and compatibility. Qi-Certified devices must operate from 0-30 watts (the Qi standard can go up to 1 kilowatt, but not for phones), pass temperature tests, and comply with Qi FOD standards. They also need to be compatible with all other Qi-Certified devices (phones or chargers), the same way that all Micro-SD cards work with all Micro-SD ports.
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