What is wireless charging and do I need it?
Apple’s
iPhone 8 and iPhone X come with wireless charging, so there’s no need to reach
for a cable any more. How does it work, what supports it and is it any faster?
The iPhone X on
a wireless charger. Photograph: Apple
The new iPhone X and iPhone 8 support wireless
charging for the first time in an Apple smartphone – but what is it, how does
it work and is it worth using?
How
do I wirelessly charge my phone?
Wireless charging
means, as the name suggests, you no longer need to plug a cable into your
smartphone to charge it. Simply placing it face up on a special mat or tabletop
is enough to start charging up your smartphone’s battery, be it the iPhone X,
iPhone 8, Samsung Galaxy S8 or any number of different smartphones
that support wireless charging.
What
do I need?
You need two things.
The first is a smartphone that supports wireless charging, or a case that you
can put on one to add wireless charging if it doesn’t come built in.
The second is a
wireless charger. These little pucks or mats come in various shapes and sizes,
from larger mouse mat-like things to small discs built into furniture, and are
available from about £10.
Is
it faster?
Samsung’s
Galaxy S8 on a wireless charger. Photograph: Samsung
In most cases wireless
charging is slower than charging via a cable for smartphones that include
fast-charging technology, such as the Galaxy S8.
Some wireless chargers
are faster than others, with modern higher-powered chargers capable of fully
charging a large battery smartphone in around two hours. They’re typically
rated by wattage, with 5W and 10W chargers common, or by output amperage, with
1A at 5V wireless chargers comparable to a standard 1A USB cable charger such
as that that comes with the iPhone 7.
What’s
‘Qi’ wireless charging?
There are a couple of
competing standards in the wireless charging industry designed for portable
gadgets such as smartphones. Most smartphones support both the Wireless Power
Consortium’s Qi and the PMA or AirFuel Alliance standards, meaning that they
will work on most available chargers.
Qi is rapidly becoming
the most popular wireless charging standard, and the one used by Apple for its
new iPhone 8 and iPhone X.
How
does it work?
Wireless charging
works by transferring energy from the charger to a receiver in the back of the
phone via electromagnetic induction. The charger uses an induction coil to
create an alternating electromagnetic field, which the receiver coil in the
phone converts back into electricity to be fed into the battery.
Ikea’s
wireless charging side table. Photograph: Ikea
They typically have to
be in close proximity to each other and correctly aligned over the top of each
other, although a set orientation is normally not necessary.
Rechargeable
toothbrushes and other bathroom accessories have used inductive charging since
the 1990s.
Other
than the iPhone 8 and X, what supports it?
Wireless charging has
been built into smartphones since the Palm Pre in 2009, with some of Nokia’s Lumia
Windows Phones such
as the 820 and 920 gaining wireless charging support in 2012. The Google Nexus
4 also supported wireless charging and Samsung has supported wireless charging
in its Galaxy S line since 2013’s S4.
A variety of
smartwatches, including the Apple Watch, Moto 360 and LG
Watch Style, can only be charged wirelessly, while some tablets such as the
Nexus 7 supported wireless charging.
Some laptops can also
be charged wirelessly, but are typically incompatible with the technologies and
standards used for smaller gadget charging.
Does
the phone heat up?
Yes, most phones and
some chargers heat up slightly on the back where the wireless charging is
taking place.
Smartphones typically heat up
slightly when being charged via cable, so the difference is small in most cases
and isn’t anything to worry about.
If it starts getting
really hot, though, it could be a problem with the battery, as with Samsung’s fire-prone Galaxy
Note 7.
Are
there any downsides?
The biggest downside
is that wireless charging cannot be performed through metal with current
technology. That means most wirelessly charging smartphones have either plastic
or glass backs, the later of which makes them more fragile.
It also may not work
through thick cases, although generally does through thin plastic cases,
dependent on the phone and the charger.
Is
wireless charging going to be a big thing?
Apple’s
new AirPower wireless charger. Photograph: Josh Edelson/AFP/Getty Images
While the standards
for wireless charging have been in flux for years, now that most devices either
support multiple standards or at least Qi, wireless charging is likely to
become a standard part of smartphones in the near future. Apple’s adoption of
Qi is likely to make it the primary standard going forward.
