What is Wireless Charging and its Range?

What is Wireless Charging and its Range?

What is Wireless Charging and its Range?


To many, the idea of being able to charge devices without connecting cables sounds like a new invention, however, it has been in existence for over 100 years. Nikola Tesla was the first to conceive the idea of wireless power transfer, although this was merely an idea on paper at the time.

Now, wireless charging is gradually transforming the way we power our devices and with promised improvements in the area of how much power can be transferred and the range, the future is indeed promising.

How Does Wireless Charging Work?

Wireless charging is based on the principle of Electromagnetic Induction. Electromagnetic induction is the production of current or voltage in a conductor by a changing magnetic flux.

For wireless charging to work, a base station (charging plate) is required. The charging plate contains wound up coils of wire that creates a magnetic field when current passes through it. This produced magnetic field has the ability to induce a current in an adjacent coil of wire without physical contact.

The batteries of devices that allows wireless charging usually have this coil of wire in their charging circuit so that current can be induced in them.

wireless charging system

Some Applications of Wireless Charging

wireless power technologies

In recent years, wireless charging has gained and is continuing to gain traction across a wide range of practical application, some of them are discussed below.

Mobile Devices

Mobile devices like smartphones, tablets, etc. can be charged using wireless technology. This eliminates the need for a wired charger which can be cumbersome to carry about. Its flexibility, convenience, and improved range make it much more attractive.

Electric Vehicles

Imagine having to charge your electric vehicles without plugging a cable. Well, that’s already becoming a reality. A transmitting pad on the ground under the vehicle is used to create a magnetic field. Electric current is being induced in car batteries by a receiving pad under the vehicle. With current technology, this set up is about 80% efficient. However, further research is needed to reduce its cost so as to foster mass adoption.

Medical Uses

Wireless charging allows for safer and efficient medical processes. Magnetic resonant technology, in particular, makes it possible to power medical devices efficiently at even longer ranges. Its applications range from portable medical devices to implanted medical devices and even surgical tools.

Others areas like wearables, Internet of Things, Infrastructure, and so on also find vast application in wireless charging.

Longest Charging Range for Wireless Charging

One of the major challenges of wireless technology is the range, i.e. how far can current be induced efficiently? Currently, there are two major standards associated with wireless charging. They are;

  1. Inductive(qi)
  2. Resonant standard

Broadly speaking, inductive wireless charging is better suited for efficiency while resonant wireless charging is suited for convenience (in terms of longer range).

However, the coil length and its thickness drastically affect the range. The longer the number of turn of coil and thickness, the greater the range.

Since smaller devices like mobile devices have coils with a smaller diameter as a result, their transmission range is limited to about 12 inches or less. On the other hand, wireless charging systems with larger coil can cover as much as 15 feet.

Future of Wireless Charging

Although for now, wireless charging is not as efficient as cabled connection, its flexibility and simplicity make it very appealing. At the moment, the efficiency of wireless charging is about 60-70%. However, it is expected to rise due to advances in wireless charging technology, thereby making it a more viable option.

Also, most of our gadgets require restructuring for compatibility with wireless charging. With the current rate of adoption, this technology might just become the next best innovation after the internet.

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