Wireless charging

Matt Pluckrose, managing director of Desktop Ideas, explains wireless charging and how it works.

Wireless charging, such as the Qi charging standard that many Android phones use, isn’t that new but, like all cutting-edge technology, it is just now starting to take off and get consumers and businesses buzzing about it.

Wireless charging isn’t magic — you still need a wire. The difference is that the wire is connected to a charging base (via mains AC) instead of into your phone. This means you can simply place your enabled Android smartphone directly onto the charger and watch it start to charge without connecting a cable. The charging base can be almost any shape or size and even be in something like your car dashboard, coffee shop tables, a portable power bank or the base of a lamp from IKEA. As long as your phone is enabled and you match the right spot on the rear of your phone to the right spot on the base of the charger, it will work.

A good example would be having a wireless charging base on your desk at work. When you’re not using your phone, you set it on the charger. When you need to use your phone, pick it up and it has a charge. Wireless charging isn’t as fast as “Quick Charging” but it’s easy and something you’re more likely to use to keep your phone topped up throughout the day. That’s where wireless charging shines — ease of use.

How does wireless charging work?

Inductive (wireless) charging uses two electromagnetic coils to create a magnetic field between two devices, ie. the coils in the charger base unit and your phone. This is the same theory behind the transformer you plug into the wall to charge your phone in the normal way. A magnetic field “creates” electricity through the difference of potential and vibration.

The coil in your phone is also connected to the battery-charging circuit, and your battery is charged using the energy induced in the magnetic field. Of course, excess heat is created as well, and that’s part of why wireless charging isn’t the most efficient way to transfer power from the wall to your battery. This is why it takes longer to charge your phone on a Qi pad than it does to plug it into the wall. 

To simplify: Your phone and the charger have coils in them. When the two coils get close enough, they use magnetism and vibration to send a small amount of power across the gap between them. This power goes through the charging circuit in your phone and charges the battery.  It costs more and takes longer to charge than it would if you plugged your phone in, but it’s far more convenient.

A word about Powermat & Apple

Qi is not the only wireless charging standard. Powermat also builds wireless charging solutions and use the same basic inductive charging and power transfer, though with a different set of standards. They have partnered with people like AT&T and Starbucks to provide base stations in public places, and using a special case or charging block attached to your phone lets you wirelessly charge. They are also partnered with General Motors, and are working to bring built-in wireless charging bases in vehicles.

While the same basic electrical theory applies to both Powermat and Qi, the different standards mean they are not compatible. Your Qi-enabled phone won’t charge on a Powermat base because the signals sent and received are different. If you have Powermat equipment, you’ll need to be sure you’re buying more Powermat equipment to get everything working. The one exception to this is the Galaxy S6 and Galaxy S6 edge, which include both Qi and Powermat standards.

Apple or iPhone do not currently support either of these standards and is rumoured to be working on their own wireless standard to be launched in the future iPhone. To use current wireless charging standards with Apple devices you would need to purchase or use an accessory such as an enabled phone case or slip pouch.

Why do I want wireless charging in my next phone?

The easy answer for this is convenience. You can charge without having to search for the right cables and plugs. Now there is a good global standard in Qi, most new Android smartphones will work with any enabled charging base. This technology will change and develop fast over the coming years and whether Qi, Powermat or Apple, we will all soon be cutting the wires and charging wirelessly.

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