How Do Wireless Chargers Work?

How Do Wireless Chargers Work?

Wireless chargers are really cool. Without the need to plug a cable into your phone, you can instead just have your device placed on a surface, through which charging simply works – but it’s a bit more complex than that, right? Like, not every phone can wirelessly charge, some charge slower, some chargers won’t work with some devices, and obviously there are limitations to wirelessly charging.

It’s not new technology, but it’s also not something that everybody uses, so let’s sort out what’s true and what’s not about wireless charging.

How do wireless chargers work?

Wireless chargers work by electromagnetic conduction. With your phone, or other wireless charging device (such as a smartwatch or headphones case) placed on a wireless charging mat or surface, electricity is transferred between a transmitter (the mat) and the receiver (the phone), heading straight into the battery.

A magnetic field is created between the two devices, and inside the phone or device being charged, there’s a magnetic loop antenna that’s used for receiving the electricity. Think about the MagSafe cases that you can buy for iPhones – the white bits on the back are basically external antennae for receiving a charge, although these will still send the electricity through the antenna inside the phone (iPhones with MagSafe cases wirelessly charge faster because of the external antenna).

Can any phone be charged wirelessly?

Not every phone you can buy today comes with wireless charging capabilities. The tech is typically reserved for more expensive phones, such as the standard Google Pixel range (excluding the ‘a’ model), the Samsung Galaxy S and Z devices, and all iPhones except SE models. As a rule, many phones below the $1,000 price point don’t have wireless charging, but it’s rare to find a phone above $1,000 without it.

Additionally, be aware that some older models won’t have wireless charging. Apple only introduced the technology to its phones with the iPhone 8, Samsung with the S6, and Google with the Pixel 3.

If you’re unsure about if your phone can be charged wirelessly, it’s worth checking the technical specifications of the model on the manufacturer’s website.

Can all phones work with all wireless chargers?

The technology that most phones use for wireless charging is ‘Qi’ – or ‘chee’, meaning life force in Chinese. Qi is a standardised technology developed by the Wireless Power Consortium and was introduced in 2009, essentially allowing any phone that supports Qi wireless charging to charge with a Qi charging pad. This includes phones and wireless chargers from Apple, Samsung, and Google, along with aftermarket accessory makers like Belkin. Even Apple’s MagSafe chargers should technically work with any Android phone that has Qi wireless charging support, although just as a complication, MagSafe chargers are specifically built for Apple’s phones, which magnetically attach to the back of iPhones. Because Android phones don’t do this, you have to align the charger and the phone perfectly, otherwise they won’t charge.

There are also some devices that are dependent on specifically made wireless chargers. The Pixel Watch, for example, will only wirelessly charge through Google’s own wireless watch charger. It’s worth looking up if your device is dependent on a specific wireless charger before purchasing one under the assumption that it will just work.

What can’t wireless chargers do?

Wireless chargers aren’t built to transfer data. It’s just not something they can do. You can transfer your data wirelessly over AirDrop, Nearby Share, Bluetooth or Wi-Fi while charging, but the wireless charger itself doesn’t have a data transfer protocol.

Wireless chargers also, typically, can’t charge as fast as phones under optimal conditions. While the top-range phones from Apple, Google, and Samsung will go from 0 to 50 per cent charge in about 30 minutes when plugged into a powerful enough charger, wireless chargers are typically a bit slower than this because of the lower wattage.

Is wireless charging safe?

Wireless charging is safe if you’re not being silly with it. Apple has issued warnings in the past about not wirelessly charging on soft surfaces and has cautioned against wirelessly charging while sleeping. The heat produced by charging could cause burns, or in more serious cases, could start fires, but if you’re not obscuring the wireless charger and don’t have it placed on something at-risk of burning (do not under any circumstances wirelessly charge under a pillow), the risks should be almost entirely mitigated.

Additionally, the EMF radiation produced by wireless charging, while scary-sounding, is safe – don’t be worried about this. “The whole wireless charging process emits less radiation than a phone that is connected to a mobile network,” according to Belkin.

And that’s the ins and outs of wirelessly charging. It remains an expensive way to charge compared to just using the cable from the box (Apple’s cheapest wireless charger, for example, costs $65, while Google’s costs $120, and Samsung’s costs $69), but can be convenient if you’re sick of plugging in cables.

Image credit: Apple/Gizmodo Australia

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