Inductive charging (also known as wireless charging) offers a way to charge compatible batteries without plugging them in. This method is most commonly used for smaller personal devices like smartwatches and mobile phones. But a new generation of induction charging technology may soon come online to quickly and efficiently recharge fleets of electric vehicles.
The genesis of induction power transfer occurred in 1894 when two engineers named Hutin and Le-Blanc proposed a system of wirelessly charging electric vehicles. Their work was based on discoveries made by famed English physicist Michael Faraday who, in 1831, first discovered the theories of magnetics and electricity that make induction charging possible.
In 2008, the Wireless Power Consortium (WPC) was formed, and by 2010 the WPC had created today’s most common wireless charging standard known as Qi (pronounced “chee”).
The underlying mechanism of inductive charging is relatively simple. An induction coil in the charging pad creates an oscillating electromagnetic field like the one created by Nikola Tesla in the 19th century. When you place your device on the charging pad, the device’s receiver coil converts the magnetic field back into electricity to charge the battery.
The size of the coils in each determines the maximum viable distance between the charger and your device. Larger coils allow a greater distance between the two pieces of hardware. Most wireless charging devices currently allow up to 50mm between the device and the charger.
Wireless charging has its drawbacks, too. For one thing, the low-power wireless charging common to mobile devices (less than 100 watts) is a slower, less efficient process. It can take up to 15% longer to charge a mobile phone via a wireless charging pad compared to a charging cable.
For another, inductive charging is more expensive. Manufacturing chargers and devices that contain the requisite drive electronics and coils create a higher price per unit (PPU) than traditional charging accessories.
And finally, nearly a third of the energy produced by an inductive charging pad ends up as wasted heat. With more than 1 billion smartphones in use today, that amounts to 225 billion watts a year of wasted electricity, according to the WPC.
That said, you can be sure product engineers are working on better, more efficient wireless charging systems. These new inductive chargers could one day make wired charging a thing of the past.