Wireless Charging Explained: What is wireless charging?
Wireless charging also is known as inductive charging as the name implies charging electronic devices without the use of a wire or cable connecting the device to its charger.
Before we go to how it works, let’s look at a brief history of how the almost seemingly form of magically charging your phone without a cord came to be.
This technology has been around for over a century. The first attempt at wireless charging was in 1864 when James C. Maxwell tried to transfer power using radio waves as a medium.
Nikola Tesla who believed wireless power transfer was possible, built the Tesla tower which was a giant coil connected to a 200-foot high tower with a ball 3 feet in diameter. Tesla pumped 300kw of power into the device; the coil resonated at 150 kHz. The experiment failed due to the fact that the power diffused in all directions. This experiment demonstrated magnetic resonant coupling.
In 2009, the Wireless Power Consortium (WPC) was established in 2008, and in 2010 they established the Qi standard
Wireless Charging Explained: How Wireless Charging Works.
The way a wireless charger (inductive charging/coupling) works is by creating an electromagnetic field to transfer energy through electromagnetic induction. It needs 2 coils. The first coil in the charger and the second coil in the object being charged(receiver). The first copper coil (magnetic loop antenna) in the charging base creates an oscillating electromagnetic field. The coil on the receiving end then takes power from the electromagnetic field and converts it back in electric current to charge the battery.
Greater distances between sender and receiver coils can be achieved when the inductive charging system uses resonant inductive coupling. (magnetic phase synchronous coupling) is a phenomenon with inductive coupling where the coupling becomes stronger when the “secondary” (load-bearing) side of the loosely coupled coil resonates.
Some factors affecting the transfer of charge can be the size of the coils. The bigger the coils or the more coil there are, the greater the distance a charge can travel.
The Qi Standard of Wireless Charging
The Qi standard was set up by the Wireless Power Consortium (WPC) in 2010. Qi meaning energy flow in Chinese defines the wireless power transfer using inductive charging over distances of up to 4 cm. the qi system uses a charging pad and a compatible device placed on the pad. Which charges the electronic device via resonant inductive coupling.
The Qi wireless charging standard has been adopted by many of the smartphone manufacturers. it is divided into 3 power specification.
The first is a low power which delivers power of up to 5 W and is primarily used in charging smartphones. Now, the Google pixel supports charging of up to 10 W with a google charging dock which means faster charging. Which has been the major weakness of wireless charging.
There is a medium power specification which delivers up to 120 W and is mostly used for monitors and laptops.
The high spec can deliver up to 1 kW of power and I used to power items such as kitchen utensils.
It is possible to get a phone that does not natively support wireless charging and make it support wireless charging. But this will require special equipment such as a specialized case or adapter. The downside of this setup is that they don’t look visually appealing.
The pros and cons of wireless charging.
Wireless Charging Explained: Pros.
• A safer way to transfer power to your phone.
• It more convenient to just put your phone on a charging dock or pad than to plug it in
• Less wear and tear on charging ports and cables
• The Qi standard wireless charging docks and pads are more popular and most wireless charging docks and pad will most likely support your phone.
• It’s more secure than charging through a cable. Malware can infect your device through the cable
Wireless Charging Explained: Cons
- Wireless charging is slow as compared to fast charging chargers. Though plans to make the Low power standard reach up to 15 W soon.
- It is not efficient. Efficiency runs as little as 30 % to 80 %. About 20% of energy is wasted in an ideal situation when charging. 10s of millions of people charge wirelessly and is a lot of electricity being wasted.
- When charging, you can not move your phone from the matt or else it wills top charging.
- Adapters and cases are expensive because the technology is expensive to produce.
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