How Does Wireless Charging Work? Electromagnetic Induction 101 For Standing Desk Users

December 19, 2020

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imovr ellipse power block review wireless charging

If you’re shopping for a desktop power module for your standing desk or treadmill desk you’re probably considering whether it’s worth the extra money to get one with a Qi wireless charging pad.

As we cover in our comprehensive reviews of power modules for standing desks, there’s almost an order of magnitude difference in price—and quality—between the cheapest, Chinese-made variety and the premium, American-made offerings. In this article we dive into everything you ever wanted to know about wireless charging of your electronic devices, so strap in for the Cliff Notes as prepared by our expert staff reviewers.

Wireless charging stand production is predicted to reach 2.2 billion annual units by 2027

In order to improve the end-user experience, global tech giants are working diligently to adopt a universal method for both charging and data transfer. There are currently hundreds, if not thousands, of off-brand manufacturers. The problem: there are just as many device types and models in production, all with slightly different charging requirements.

How do you make sure that the wireless charging stand you purchase is the right choice for your device? This quick-read article will answer some of the most common questions around wireless charging and equip you with the knowledge to make an educated purchase.

The Most Common Questions Our Readers Have About Wireless Chargers:

  • How does wireless charging work?
  • What is electromagnetic induction?
  • What is Qi wireless charging?
  • Wireless charging not working
  • Is wireless charging faster?
  • Is wireless charging safe?
  • Is wireless charging bad for your battery?

How Does Wireless Charging Work

Wireless charging works by electromagnetic induction allowing for the air around a device to hold an electromagnetic charge which the device can transfer into electricity. 

Electromagnetic induction is created when a charging coil produces an electromagnetic field that the receiving coil in your device can pick up on when carefully aligned and placed close to each other. Unlike magnetic resonance, electromagnetic induction doesn’t require the coils to be resonating at the same frequency and is the standard method of wireless charging for mobile devices. It is also the approach behind Qi, the industry-leading wireless charging stand technology.

In addition to electromagnetic induction, wireless charging works through radio waves and magnetic resonance.

Radio Charging:

Used in devices like wireless keyboards, watches, and earbuds. Good for low power levels and close proximity between charger and device.

Magnetic Resonance:

Used for larger devices like vacuums and cars. Requires a copper coil in both the charger and device to be resonating at the same electromagnetic frequency, and when placed within a short distance from each other, will transfer energy through the air. More complex, higher power levels, and less efficient than radio charging or inductive charging but can pass through thicker surfaces and is less sensitive to the physical alignment of the coils.

What is Electromagnetic Induction?

Electromagnetic induction is the energy produced by two magnets opposing each other’s force. This can occur in a number of ways, one of which exists between electromagnetically charged coils housed in charging devices and mobile electronics. What’s important to highlight is that this energy travels through the air, allowing wireless charging stands to deliver power to your battery without the need for a cable.

While wireless charging may sound innovative, the technology has been used to power small appliances since the early 90s, and electromagnetic induction itself was discovered in 1831 by Michael Faraday.

The real innovation behind wireless charging stands is the ability to create a universally compatible protocol that major tech companies around the world can adopt. This is exactly what the multinational Wireless Power Consortium (WPC) with its industry-leading Qi wireless technology.

What is Qi Wireless Charging?

Qi (pronounced “chee”) wireless charging stands have become the leading global technology in this field. Designed by the WPC, Qi is the safest, most reliable, and most regulated wireless technology on the market

In order for charging devices to gain Qi certification they need to:

  • Pass compliance testing for safety and performance at one of 11 independent test labs around the world
  • Pass interoperability testing by one of two Interoperability Testing Centers around the world
  • Be compliant with the latest version of Qi specifications
  • Mfg. must be a Qi Logo Licensee

Wireless chargers without Qi certification have been reported to produce temperatures upward of 200 degrees Fahrenheit – which is enough to cause 3rd-degree burns – pose serious fire hazards, melt phone covers, and permanently damage battery health. 

In addition, a number of the off-brand wireless charging stands our product testing team purchased on Amazon didn’t have any labeling or indication of exact input and power ratings whatsoever, which is illegal in the United States. Unfortunately, foreign manufacturers that ship these products into the US face significantly less regulatory supervision than domestic manufacturers. 

On top of that, Amazon continues to reject responsibility for property damage due to unregulated consumer electronics. What this means for you is that when you purchase an off-brand wireless charging stand without Qi certification, not only are you putting yourself and your property at risk, but your chances of holding Amazon or the manufacturer liable are slim to none.

Choosing a Qi certified wireless charging stand gives you peace of mind knowing that your devices and property are safe, are backed by multiple stages of inspection and verification, and will continue to be compatible with your future devices.

Wireless Charging Not Working

There’s a few common reasons for wireless charging not working:

  1. Not all mobile devices are compatible with wireless charging stands, although this is rapidly changing.
  2. Your device case might be significantly slowing charging speed.
  3. Coil alignment for electromagnetic induction is sensitive and may require adjustment. (Very easy fix)
  4. Interstitial power devices may be turned off or have a blown fuse.

Does My Phone Have Wireless Charging?

How to charge wireless devices can vary, but a more common question is “does my phone have wireless charging at all?” It may not be obvious at first, in fact, most manufacturers don’t explicitly label wireless compatibility on the device itself, but wireless charging only works if your device supports it. If you’re wondering whether or not your device has wireless charging, the following chart highlights support for popular phones:

Apple iPhone 12, iPhone 11, iPhone XS Max, iPhone XS, iPhone XR, iPhone 8, iPhone 8 Plus
Samsung Galaxy Fold, Galaxy S10, Galaxy S10+, Galaxy S10E, Galaxy Note 9, Galaxy S9, Galaxy S9+, Galaxy Note 8, Galaxy S8 Active, Galaxy S8, Galaxy S8+, Galaxy S7 Active, Galaxy S7 Edge, Galaxy S7, Galaxy S6 Edge+, Galaxy S6 Active, Galaxy S6 Edge, Galaxy S6
Microsoft Lumia, Lumia XL
Google Pixel 3 XL, Pixel 3, Nexus 4, Nexus 5, Nexus 6, Nexus 7
Sony Xperia XZ3, Xperia XZ2 Premium, Xperia XZ2

If you don’t see your phone on this chart or you’re inquiring about a different device type altogether, simply enter the model number of your device into Google (or your favorite search engine) and add “wireless charging compatibility”.

If your device isn’t compatible with wireless charging stands you might still be able to purchase a converter that plugs into your device charging port and hides underneath your protective case.

Does Wireless Charging Work With The Case On?

Wireless charging works with protective cases but there are some caveats. Electromagnetic induction serves as a reliable method of wireless charging when both devices are aligned properly and typically within a half inch of each other. While most cases will not prevent your device from receiving a charge, it is common that thicker cases will dramatically reduce the speed of charging and/or increase the heat retention of the device. 

Recall that electromagnetic induction is less powerful than magnetic resonance, requires the coils to be very close to each other, and that the device is aligned carefully on the wireless charging stand. As a result, thick protective cases increase the distance between coils and the density of space between them, leading to greater resistance within the electromagnetic field.

If this is the case (pun intended) in your situation and wireless charging still isn’t working, we recommend removing your device case during charging and you should notice a substantial increase in charging speed.

How to Turn on Wireless Charging

Turning on wireless charging is automatic. Wireless charging stands detect your device as soon as you place it on the charging pad. If your wireless charging stand is plugged into a power strip or interstitial device, simply make sure that it’s turned on as well and that the fuse is good.

As mentioned, proper coil alignment is important for electromagnetic induction to work. When placing your device on a wireless charging stand, position it so that it resets evenly and flat against the charging pad and you will receive the optimal watts available. Learn more about watts, amps, and volts for mobile device charging.

Is It Faster?

There’s a lot to consider when calculating charging speed. Wireless charging stands typically provide 5, 7.5, or 10 watts of power but can currently reach up to 15 watts. That said, the general consensus is that a 5W wireless charger is actually a bit slower than a 5W cable charger, however, a 15W wireless charger will certainly be faster than a 5W, or even a 10W cable charger, so the difference is marginal.

Reasons for this include the factors listed in previous sections above such as poor alignment, thick protective cases, and uncertified off-brands with questionable power output specs. Other factors that affect wireless charging stand speed include the phone’s current battery level and the age or health of that battery.

Charging Speed With Multiple Devices

Because electromagnetic induction requires careful placement of your device correctly on the wireless charging stand, pragmatically speaking, it can be challenging to charge multiple devices at once with a single pad configuration. Wireless charging stands with two or more pads that are designed to charge multiple devices will do so, however, if each pad is sharing a single circuit the overall charge provided to each device will be reduced. 

Overall, wireless charging is a better option for stationary workspaces where your device can rest on the charging pads and remain within hands-reach. 

Is Wireless Charging Safe?

There are two factors to consider when discussing the safety of wireless charging and electromagnetic induction.

  1. The manufacturer’s quality standards and safety regulations
  2. The amount of power being transmitted through the air

Manufacturer Quality Standards and Safety Regulations

Not all manufacturers are equal, by any stretch of the imagination. Most of the wireless charging stands you’ll find on the market won’t be UL or ETL listed and in some cases may not even have any form of labeling or power rating indicated on the device itself. Unregulated consumer electronics pose a higher risk for fire, property damage, personal injury, and come with evasive and complicated warranties where it becomes easier to simply buy another product.

The WPC seeks to protect consumers from these risks, and with its industry-leading Qi wireless charging stand technology, has provided a safe, reliable, and universal solution that all of the major tech giants around the world are quickly adopting in modern mobile devices.

The Amount of Power Being Transmitted Through the Air

The amount of power being transmitted through the air during electromagnetic induction in wireless charging stands is so low that the World Health Organization (WHO) has determined there to be no known health risks to humans. 

Is It Bad for Your Battery?

The WPC asserts that wireless charging is no more harmful to your battery than charging by cable. And this makes sense when you consider how a battery can be damaged (outside of physical impact). All batteries lose total capacity over time and the rate at which they deteriorate varies. Popular brands such as Apple claim to retain 80% of original health over 500 charging cycles.

Modern devices have protection against “overcharging” but there is a common misconception over what actually constitutes overcharging. Old devices, especially when matched with improper chargers, could receive more power than needed and quickly result in legitimate battery damage. Today, however, overcharging is more a factor of time spent at (or near) 100% charge.

Return to our round-up of the top-rated power modules for stand-up desks.

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