How does wireless charging work?

Aluminium dual charger charging iPhone 12 and Sonos Roam

About wireless charging

In recent years, wireless charging has become more commonly available in our daily lives. Already over 500 types of devices, including phones, are in the market which can be charged on our wireless chargers. You may have been using wireless charging for many years already if you possess an electrical toothbrush: you just put it on the holder and it starts charging.

The principle to charge your smartphone or smartwatch wirelessly is the same: just put your phone on a wireless charger or charging pad and it starts charging. Very convenient, no need to connect a cable first. But how does wireless charging work?

The birth of wireless charging

The way wireless charging works is by something which is called magnetic induction. This was discovered in the 1830’s by Michael Faraday. He discovered that when you move a permanent magnet in and out of a single loop of wire, it induces a voltage. Linking electricity with magnetism. Inductive charging was born.

Seeing is believing

Does the concept of inductive charging still sound kind of vague? Let’s explain by conducting an experiment:

Take a permanent magnet – like the ones you stick on your fridge. Connect a light bulb to a simple loop of copper wire. Now move the magnet quickly back and forth, bringing it closer and further away from the loop. The bulb will start lighting up a little!

So what just happened? Why did the bulb light up? By bringing the magnet back and forth, you change the magnetic field experienced by the loop, which induces a voltage in the loop. The voltage created is in some way comparable to the voltage of a battery.

How does wireless charging work with induction?

Wireless charging your toothbrush, smartphone or any other device works similar as we just showed with the light bulb. In practice, we don’t have a moving magnet but we do have another loop of copper wire, a so-called induction coil. This will carry a changing current at high frequency. These coils are for instance perfectly visible in our Liberty glass wireless charger.

The changing current generates the changing magnetic field. This part of the wireless charging system is called the “transmitter”. The part inside your phone, smartwatch or toothbrush is called the “receiver” and is charged in the same way as the light bulb.

Wireless Charger 4-in-1 with iPhone, Airpods and Apple Watch

Is wireless charging safe?

Magnetism and inductive charging are always perceived as being a bit mysterious because you can’t see them, you can’t feel them and you can’t smell them. To build an efficient wireless charging system, you need to limit the magnetic field closely around the copper wire loops.

This is done by special materials called ferrites. These are conducting the magnetic field very well, much better than air does. Therefore, the magnetic field has a preference to flow though the ferrite instead of through the air. Because of that, hardly any field comes out of the wireless charging system and is therefore inherently safe.

So what is the Qi standard?

Qi sets the standard for safety when it comes to wireless chargers. The Qi certification is governed by the Wireless Power Consortium (WPC). The WPC is a group of leading companies that cooperate in continuously defining, maintaining and developing the Qi standard for wireless charging.

As a proud member of the WPC, we are offering wireless chargers with the latest technology and safety standards. With a Zens charger you can always safely charge your device, even at night.

ZEMSC2P - Zens Modular Stand Wireless Charger With Extensions And Devices

Find your wireless charger

Frequently asked questions

Can I charge multiple devices at the same time on one wireless charger?

Yes, Zens has developed wireless chargers for both individual and shared (dual chargers) use. Depending on the model, you can wirelessly charge one or two phones at the same time by placing them next to each other on the dual charging pad. We also have 3-in-1 chargers and 4-in-1 chargers that can charge up to 4 devices simultaneously. Want to go all out? With our Modular Series chargers you can charge up to 6 devices at once. Talk about convenience.

Can I charge my iPad or tablet with a wireless charger?

In some cases you can charge your iPad or tablet via our wireless chargers, but not wirelessly. Currently there are not many tablets that can be wirelessly charged. Still want to charge your tablet via our wireless chargers? Choose a charger with a USB-A port. Via this port you can connect your tablet to the wireless charger, thereby saving space of an additional power socket being used.

Can I leave my phone case attached while charging?

Yes, you do not need to remove your case before charging. All Zens wireless chargers work with most lightweight cases (< 3 mm). Just to be sure, it is recommended to take phone cases with metal lining off before charging.

Does it matter how many coils a charger has?

Most wireless chargers only have 1 charging coil. This means that you have to make sure your phone is aligned with the charging coil to start charging. This is no problem if you just pay attention when placing your phone on a charger. If you want freedom of placement, without paying attention if your phone is aligned with the charger, you should choose a charger with more coils. You will get a bit more freedom of placement with our 5 coils dual charger. If you want ultimate freedom of placement you have to check out our Liberty wireless chargers that pack a whopping 16 coils.

How many watts do I need?

How many watts you need mostly depends on what your phone or device can handle and when or how you want to use the charger. Do you want the fastest charger possible to fast charge your device? In most cases a 10W charger or 15W charger will suffice, as the maximum amount of Watts for fast charge is capped by smartphone manufacturers. For Apple Fast Charge this is 7,5W and for Samsung Fast Charge this is 9W. Make sure your phone actually support fast charge such as Apple Fast Charge or Samsung Fast Charge. If you want to charge your device at night, a 5W charger will also suffice.