How Wireless Charging Works and Why It's Terrible

You’ve seen wireless chargers, the tech is now as common as the

smartphones they power. But did you know that they come with a big catch?

Two actually: wireless charging is inefficient and it may lead to accelerated battery degradation.

You can find a link to our complete test results in the description but the gist is this:

Efficiency between wireless chargers varies, but wired is the most efficient.

Some wireless chargers may be damaging your battery if the

battery packs temperature regularly exceeds 30C.

But let’s start from the top. What is the difference between wired and

wireless charging beyond the whole cable thing?

With wired charging, energy transfers from the outlet through a cable and directly to

your phone. It's the most efficient means of charging we have at home, but it’s not perfect.

Our tests with state-of-the-art GaN chargers show that even the

best wired setups lose about 35% of their energy during normal operation.

It took 18.25Wh to charge our iPhone 15 Pro’s 12.7Wh battery.

It’s not ideal but it’s the best we have Critically,in our all our

wired charging tests the battery temperature never exceeded 29C.

Wireless charging seems just as straightforward. You drop your

phone on a pad and the electricity magically travels to your phone and charges it. No cables,

no fuss. But the journey from pad to battery is not as direct as you might think.

In fact, the electrons from the pad never reach the phone's battery.

Inside the phone you’ll find a wireless charging coil made to receive energy from

a charging pad. The pad has a corresponding coil designed to interact with the phones coil.

By manipulating alternating magnetic fields, the pad can create current

inside the receiving coil thereby creating a current that can charge your battery.

If you think this sounds like a lot of work then you’d be right. Generating a magnetic field to

induce a current “wastes” a lot of energy and it’s a big reason why wireless charging is

inefficient. Other factors in energy loss include misaligned coils and distance between coils.

So in long-range wireless charging,

like some products advertised online or even wireless EV tech,

the energy lost will increase as distance between the transmitting and receiving coil increases.

Electric cars aside, Apple’s MagSafe and

the Qi2 wireless charging standards do provide a partial solution.

In order to mitigate the alignment problem, a set of magnetic coils in the charger line

up with the opposite polarity of magnets in the back of your phone. This ensures a

perfect alignment and maximum efficiency when transferring energy between the two coils.

Despite this, 36% more energy is lost when compared to wired charging while the battery

temperature peaked at 35C. And remember, this is the best case scenario for wireless charging!

In our worst case scenario tests, a misaligned 15 Pro on an AmazonBasics

wireless charger saw a whopping additional 104% energy consumed with charge times

increasing two fold. Worse still, the battery temperatures climbed and remained above 40C.

So not only is energy consumption substantially increased with a misaligned battery,

but there is also a noticeable amount of heat transferred to the battery.

And this brings us to our final charger, the Tesla Wireless Charging Platform.

I’m sure Elon thought it was mighty cool to stick this many transmitting

coils across the pad but if our earlier tests prove anything it’s that every

single one of these coils will be out of alignment with your device.

This results in extended charging times and a toasty battery,

very similar in profile to what we saw with the misaligned AmazonBasics charger.

And the data proves it. No matter how you place your phone on the Tesla

Wireless Charging Platform, you’ll experience extended charge times,

higher energy consumption, and higher device temperatures.

The Tesla charger caused our device battery to hit

40C for extended periods and remained in the high 30’s throughout our tests.

The 2020 pandemic fueled a 37 % increase in wireless charger

purchases globally. That same year, the wireless market was valued at $12.7B and

estimates suggest that the market will grow to $185B by 2030 across all categories.

Is the convenience of not dealing with cables worth this hidden environmental cost? Yes or no,

wireless charging is here to stay. Just remember, efficiency varies widely among

different chargers. If you're going wireless, choose wisely. Look for Qi2 and MagSafe-certified

devices for the least waste and consider the environmental impact before going wireless.

For more information about how we conducted our tests,

be sure to check our blog post linked in the description.

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