Wireless chargers have revolutionized the way that we power up our devices, allowing for a new level of convenience and everyday use of better technology. But do you know the secret to good wireless charges? We do, and it is the number of coils!
The secret to good wireless chargers is the number of coils because more coils mean more electromagnetic power being transferred from more places. Your device or devices will charge more quickly with multiple coils and without needing to be carefully placed in one spot on the charging station.
Read on to learn more about how wireless chargers work and why multi-coil designs are important.
How Does a Wireless Charger Work?
Wireless charging was first invented by Nikola Tesla in the late 19th century when he figured out a way to transmit electricity through the air using a magnetic field. Since then, the technology has evolved in countless practical applications, including in the medical, automotive, and manufacturing industries.
There are now several different wireless charging techniques commonly used today. The most popular of these relies on an electromagnetic field created between two copper coils. This kind of charging requires the device to be held close to the charging station. And this is the wireless charging technique you’re most likely to find in a smartphone, like the iPhone, Samsung Galaxy, or Google Pixel.
This kind of charging is also known as non-radiative charging because it relies on inductive electromagnetism rather than radiative. The second kind of wireless charging uses radiative electromagnetism, which can charge an object several centimeters away. Like the first technique, this strategy depends upon a magnetic field inducing a current within a copper wire coil.
How Copper Coils Power Wireless Chargers
Copper coils contribute to the wireless charger by providing a magnetic field. Basically, an electric current runs through the coil, creating a magnetic field perpendicular to the flowing current’s direction. This magnetism is directly related to the amount of electricity flowing through.
This magnetic field then creates a current in a receiver antenna, transferring the original source’s electrical power to the receiving source. A couple of things increase the amount of distance that a charge can travel between sources, including the size of the coils and the number of coils.
Because the copper coils used in smartphone chargers are relatively small, they require close proximity to charging. Car charging systems, by contrast, allow for a power transfer over much greater distances due to their many large coils.
In addition to increasing the distance at which you can charge your phone, having multiple copper coils gives you flexibility in connecting your device to the charger. When you have numerous coils, you create multiple points where the device can sit for an optimal charge.
Some chargers recognize the location of the device and power just the coil that’s best matched with it, while others maintain electrical currents through all coils for a more powerful charge.
How To Find a Good Wireless Charger
A good wireless charger charges your device efficiently and doesn’t require careful placement in one precise spot to work. Instead, it should work at a slight distance and provide some room for error in how it recognizes and transmits power to your device.
We have done much research on this subject and have had many disappointments in the past through trial and error. We have experimented with many wireless chargers and written many articles on the subject.
Please check out some of our other articles like “7 Questions About Wireless Charging With A Thick Smartphone Case” and “What Are All Of The Smartphone Charger Types?”
Why Does the Number of Coils Matter in a Wireless Charger?
The number of copper coils that a wireless charger has influences the range at which you can charge, the amount of power being transferred at a given time, and the number of ways you can align your device with the charging station. Multiple coils can be energized at one time for a greater power transfer or one at a time for flexibility.
A wireless charger can only deliver as much power as it receives. The amount of copper coils your charger has increases the rate of power transfer. But the charger also needs to be receiving enough electrical power to charge the device quickly.
To have a fast charging speed, most wireless smartphone chargers need a 10-watt charger. But most iPhones come with a 7.5-watt charger and used to be packaged with a 5-watt charger. Obviously, through the general public’s use and trial and error, finding a fast-charging wireless charger requires some research and an investment in an upgrade.
Wireless Charger Product Recommendations
In 2017, Apple announced a product called AirPower, meant to charge multiple devices at once through the use of between 21 and 24 copper coils. However, this product was ultimately canceled due to several engineering problems, including overheating and issues with interference between different sets of coils.
However, other manufacturers have since developed multi-coil technology that charges devices quickly and effectively without overheating or having problems with interference. The most prominent on the market are the Zens Liberty, the Base Station Pro — from Nomad — and the SliceCharge Pro 6-Coil Wireless Charging Mat.
The Zens Liberty Wireless Charging Pad uses 16 copper coils to deliver an effective charge to multiple devices, no matter how they’re positioned on the pad. It also charges quickly, with a 15-watt charging power for up to two devices, either iPhone or Android. You are paying a premium for this device but get a very nice and efficient charger.
This charger is powered through a USB-C port and has a USB-A port for plugging in any additional devices. This charger is also sizable, with a footprint of 8.8 x 5.3 inches (22.35 x 13.46 cm), and has a quiet fan that prevents it from overheating. Additionally, the Zens Liberty Wireless Charging Pad is covered in 100% wool for a warm look and a soft surface.
The Nomad Base Station Pro can charge up to three devices with any placement due to its 18 coil design and its 10-watt charging capacity. It has a padded leather surface for your devices to rest on and both a USB-A and a USB-C port for charging. As you can see from the picture above this is a whole new level of design and technology.
This charger can be used up to 10mm away, including through thick phone cases like the Otterbox. It’s compatible with iPhone and Android and can charge devices from zero to 100% within 4-5 hrs. A few things that can cause a suboptimal charging time include charging in a room warmer than 74°F (23.33°C) and placing the charger on top of an insulating surface, like carpet.
At this time, the Nomad Base Station Pro cannot charge the Apple Watch, which has a separate set of requirements for coil size and charging type.
The SliceCharge Pro 6-Coil Wireless Charging Mat can charge up to three devices at once, including the Apple Watch. Its multi-coil design allows you to charge several devices at once and means that you can place the devices anywhere on the charging mat without worrying about precision.
This mat comes with an optional charging stand, which creates a comfortable visual effect. It has a maximum of 10-watt power output per every two devices and 5-watt power output for the Apple Watch. The total maximum output of the charging mat is a powerful 30 watts.
In addition to being compatible with Apple products, this charging mat is compatible with a wide range of Android products. It’s rather sizable, with dimensions of 8.26 x 4.13 inches (20.98 x 10.49 cm).
The secret to good wireless chargers is a multi-coil design because multiple coils allow devices to charge faster and at more different positions on the charger. With numerous coils, you don’t need to worry about aligning your device perfectly on the charging station, and you can be sure that your device will power quickly and effectively.
- Computer World: Wireless charging explained: What is it and how does it work?
- CNN: Our guide to finding the right wireless charger for your device
- Copper and Electromagnets – Association for Science Education
- The Verge: The Zens Liberty is the AirPower Wireless Charger That Apple Couldn’t Make
- Sonny Dickson: What Really Happened to Apple’s Airpower?
- The Verge: The most promising AirPower alternative isn’t ready yet
- Hard Cider Labs: Slicecharge Pro 6-Coil Wireless Charging Mat