How Does Wireless Charging Work?

Today, the question “How does wireless charging work?” tends to be prompted by those intrigued by how their latest mobile phone or Bluetooth headset charges without a cable. In fact, even in mobile phones this technology has existed for almost a decade. Early movers, Nokia, launched the Lumia 920 with integrated wireless charging in late 2012, more than 8 years ago! Today the technology is integrated as a common feature by all major mobile phone manufacturers, largely following the inclusion by Samsung in its flagship Galaxy S6 range launched in March 2015 and Apple’s iPhone 8 and X models launched in September 2017.

So where did wireless charging come from and why is it being integrated into so many devices?

Many of us have been using wireless charging for years as part of our daily routine, probably without even realising it! Rechargeable electric toothbrushes have incorporated similar technology since the early 1990s. The origins of wireless charging, however, date much further back to the late 1800s, since its reported invention by Nikola Tesla. The “Tesla coil” which essentially laid the foundations for wireless charging technology, was just one of Tesla’s many inventions which include the dynamo and the AC induction motor.

Wireless charging as it is implemented today uses electromagnetic induction to transfer power between coils, using the same principals Tesla derived back in the 1800s (pictured). Whether delivering milliwatts to power a sensor or several kilowatts of power to charge an electric vehicle, the general principals are the same. In simple terms, modern devices such as mobile phones, audio headsets and wearables embed miniaturised receiver coils in order to receive power transferred via transmitting coils embedded in a wireless charger. When the two devices are placed within range of each other an electronic “handshake” occurs and then using power management technology, power negotiation takes place allowing the receiving coil(s) to “ask” for power to be supplied via the transmitting coil(s). A current is induced between the two coils and is supplied either directly or to the battery of the receiving device. Several factors determine how efficient the power transfer is but generally, the closer the alignment and shorter the distance between the transmitter and receiver coils, the more efficient the power transfer is.

Qi Wireless Charging

Qi is the global interoperability standard for wireless charging, derived by the Wireless Power Consortium (WPC). Use of the Qi standard provides a universal approach to wireless charging across phones, tablets and wearables. The Qi standard also incorporates several safety features providing manufacturers with a certification program for their products and peace of mind for purchasers and deployers of Qi certified goods. Aircharge is a proud board member of the WPC.

A wireless charger certified to the Qi standard uses tightly coupled inductive technology, transferring energy via electromagnetic induction. An induction coil in the charger is used to create an alternating electromagnetic field, which the receiver coil (e.g. in the smartphone) converts back into DC power fed into the battery.

The wireless charger and phone must be in close proximity (typically within 10mm). In the majority of solutions, the receiving device is aligned directly on top of the charging coil(s) to maximise efficiency. Nevertheless, a much easier and more convenient solution than cable charging.

Qi wireless charging doesn’t stop at smartphones, it plays a role in keeping wearables, headphones and other accessories topped up too. One example is the Apple AirPods, the generation 2 and AirPods Pro both have wireless charging integrated within the AirPod Charging case.   

Where You May See Wireless Charging and What Does it Look Like?

With over 5000 Aircharge wireless charging locations across 55 different countries, it’s likely you’ve already come across a wireless charger in a public venue before and if not, we’re working on bringing it to your region soon. Aircharge has built an extensive ecosystem over the past 8 years, with partners who offer wireless charging across many industries, including food & beverage, hospitality, office, retail, transport, events, sports venues and automotive. All of these venues can be found on the Aircharge locator app, download it from the app store here. Below are just some of the examples of where you may come across Aircharge’s wireless charging solution in public and how the chargers versatile design incorporates into a range of furniture.

Wireless Charging in Food and Beverage

Aircharge has expanded into a total of 17 global territories with McDonald’s (pictured), but is deployed in plenty of other F&B brands across the globe too. Including household names such as KFC, Yo Sushi, TGI Fridays, Hesburger, Pret a Manger, Starbucks and more.

Wireless Charging in Transport

Pictured on the left is Aircharge's collaboration with commercial interior supplier Baker Bellfield to provide a subsurface solution for South Western Railway trains in the U.K.

Pictured on the right is Aircharge's collaboration with Bus service provider Optare to provide commuters with a means to charge their phones.

Wireless Charging in Hotels & Casinos

Aircharge’s glass finish solution with services, installed into the LINQ Hotel and Casino Las Vegas, offering users mobile phone wireless charging and associated digital services.

Benefits of Wireless Charging

Convenience

Wireless charging isn’t just about convenience when you’re out in public, there are now over 100 models of car which offer wireless charging in the cabin and for many it’s a much tidier and appealing solution for the home too.

Battery Health

Having the convenience of and access to wireless charging in multiple locations throughout the day also helps you maintain a healthy phone battery. It is advised to top up your phone battery little and often rather than charging a full battery cycle from 0 – 100%. It is best to keep your phone battery over 50%, so the convenience of charging wirelessly helps to support this.

Cleanliness

The use cases for smartphones now are vast! They are used for entertainment, work, travel and payment as much as they are used for communication. They have become our personal access point and replaced a number of items we no longer need to carry in addition. Not only is it much easier just to drop your phone on a wireless charger opposed to searching behind the dusty cabinet for a cable that fell after you snatched for your phone 2 hours before, dirt and germs that are transmitted between cables, connectors and your hands which subsequently end up on your touch screen can be greatly reduced.

Waste Reduction

The benefit of a universal charging solution which is backwards compatible, means that our next generation smart device will still charge on the Qi chargers we already own or are deployed in public venues, cars, public transport etc. In the future this could lead to a large reduction in redundant chargers and the requirement for manufacturers to provide a power adapter and cable with every new device they ship. Not only does this reduce clutter at home but it reduces the amount of landfill waste associated with high-volume consumer goods each year.

Ready to make the move to wireless charging?

Take a look at our compatibility page to see if your device is capable of charging wirelessly and then take a look at our e-shop here to find the wireless charger which suits you. To receive an exclusive 20% discount, sign up to our newsletter with your name and email address below.

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