What You Need to Know About Wireless Charging
How to improve your battery life is one of the most pressing concerns for all smartphone users. Until our devices offer week-long battery life, charging on the go will remain a reality for us all.
The good news is we may not have to remember to pack our chargers for too much longer.
The era of wireless charging is almost upon us, with airports, car makers and restaurant chains installing charging stations.
But while the new Samsung Galaxy S6 smartphone has been designed to work with all wireless chargers, the picture is not so clear for everyone else, with competing standards holding the technology back.
What is Wireless Charging?
The most common form of wireless charging is often also called inductive charging. It uses an electromagnetic field to transmit energy between two objects — a charging station, attached by wire to a normal power socket, and a device containing a battery and the appropriate wireless charging hardware.
When the two come into contact, the battery starts charging; charging ends when contact is broken. In the future, charging could potentially occur when they are inches apart or further.
The benefits are obvious. There are no wires, no fiddly USB plugs . It’s also potentially safer — electric toothbrushes have been using inductive charging for years without fear that water and the electrical current are going to come into contact.
Now, it’s moving into smartphones and other mobile devices, and wireless charging is about to go mainstream.
The long term goal is for airports, hotels, coffee shops and more businesses to install charging stations. Instead of having to carry a charger and plug it in, you can simply set your phone on the table to top up the battery.
Before that happens, though, the issue of standards needs to be resolved to ensure that all chargers and devices can work with each other.
Like all relatively new technologies, wireless charging has several competing — and incompatible — standards.
While it’s not quite as exciting as the VHS versus Betamax battle of the eighties, or Bluray vs HD DVD a decade ago, the outcome will likely be the same: one standard will win, and only then will the technology achieve widespread adoption.
Once the industry settles on a single implementation of wireless charging for mobile devices will we start to see docks installed in airports, hotels, cars and beyond.
It isn’t just the tech industry involved in the standards war. As it stands, Qi (pronounced Chee) is the leading standard for consumer use and is being supported by McDonalds, but PMA (from the Power Matters Alliance) offers greater features for businesses, and counts Starbucks among its members.
Qi is the standard developed by the Wireless Power Consortium, which was founded in 2008 and has over 200 members, including Microsoft, Google, HTC, Sony and Samsung.
Qi is an inductive charging system that uses tightly coiled wires to produce and receive the electromagnetic field. The standard specifies a transfer of around 5W, which is similar to a standard smartphone charger.
The standard produces an efficient transfer of power, but is prone to the misalignment of the coils in the charger unit and receiving device, which in turn can cause compatibility in products that were not explicitly built to work with one another. It also requires one coil on the charging station for each device.
Qi has been adopted to a large extent by Google and Android device manufacturers.
It’s supported in Google’s Nexus smartphones , LG’s flagship devices including the new G4, and high-end Samsung phones including the Galaxy S6. Windows Phones from Microsoft/Nokia also often support Qi, as do BlackBerry handsets.
Furniture store IKEA has recently announced a range of tables, lamps and other products with integrated Qi charging.
PMA and Rezence
PMA comes from the Power Matters Alliance, founded by Proctor & Gamble and Powermat Technologies in 2012. It has over 60 members, including Samsung, Sony, Motorola and Microsoft.
The PMA standard (sometimes also referred to as Powermat) was also based on inductive charging, but in early 2015 the Alliance announced plans to merge with A4WP, the Alliance for Wireless Power.
A4WP’s standard, Rezence, uses resonant inductive charging. This also uses the coils approach to electromagnetism, but is more tolerant of coils that aren’t aligned. This means multiple devices can be charged on a single charging pad, and also potentially be charged at distance.
One of the things that makes PMA attractive to businesses is that, unlike Qi, it isn’t anonymous.
PMA assigns a unique ID to every device, giving businesses vital information on where and how you’re using the service. Potentially, it could even be used for marketing purposes, although that doesn’t happen at the moment.
The major downside is that even many big tech brands are member of the Power Matters Alliance the PMA standard currently has very little native support in mobile devices. The Samsung Galaxy S6 does offer it, as did the AT&T version of the LG G3 (all other versions of that device had Qi instead).
If you want to use PMA charging otherwise, you’ll need add an accessory to your device, normally in the form of a sleeve or dongle that plugs into the charging port, as is the case if you ever use it at Starbucks.
Intriguingly, the PMA is also working with a company called Energous, whose WattUp technology uses radio frequencies to transmit power to any device requiring less than 10W (such as smartphones, wearables and headsets) within a 15 feet radius.
Energous is hoping to have products available based on its technology by the end of 2015, or early 2016.
When it comes to wireless charging, the elephant in the room is Apple. The company is yet to offer wireless charging for its iPhones (the Apple Watch does apparently use inductive charging based on Qi, but is not compatible with other Qi chargers), but it seems only a matter of time.
Apple hasn’t always been keen to adopt standards, much less take part in a standards war. If the company chooses sides it may tip the balance one way or the other, but there’s also a likelihood that it offers its own proprietary solution instead.
For now though, the standards battle will continue. Qi’s greater traction in the consumer market means that it is the one you’re most likely to encounter.
But the relative strengths of competing technologies, as well as those emerging, mean that could yet change before the industry makes its choice.
What are your experiences with wireless charging? Does your smartphone support it, and have you encountered compatibility issues? Let us know in the comments.