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    Long Range Qi Charging Is Closer Than You Think

    • 4 min read

    Long Range Qi Charging Is Closer Than You Think

    Even though the concept of delivering power through the air isn’t exactly new by any means, it wasn’t until just a few years ago that engineers finally settled on a practical way to do it. What we see nowadays with Qi chargers is actually a continuation of a concept demonstrated in the late 19th century.

    The journey has undoubtedly been long for wireless charging as a technology and it seems that even though Qi charging is making major strides, there is still a long way to go until long-range wireless charging becomes a tangible reality. If anything, it is the non-functional requirements of the technology that represent the biggest design hurdles, not the practical systems.

    So those of you who might be wonderingwhen long range Qi charging will finally become a reality might be delighted to know that several R&D centers are already working on a functional prototype to be released no later than 2024. As far as we understand, the biggest challenge is figuring out how to make the power transfer safe and secure.

    Not many people realize this but the human body has a specific tolerance for radio-frequency electromagnetic fields. These frequency standards are already enforced by most governments around the world and they mostly deal with the absorption rates of any radio-frequencies in any given environment.

    Concerns about interference and efficiency

    One of the biggest issues with developing a long-range wireless charging system is the potential for interference. Here, we refer to RFI measures and the electromagnetic fields generated by any product in a specific environment. Bear in mind that it wouldn’t be safe to have the charger interfere with essential appliances or devices in the room, more so if we’re talking medical devices.

    We also have to talk about RFI in regards to NFC receivers, Wi-Fi reception, mobile phone base stations, and car electronics. It needs to be said that the operating frequency for standard wireless power transfer will have to exceed 6.78 MHz so as not to interfere with wireless networks and mobile data transfer connections.

    There is also the issue of efficiency that needs to be taken into consideration. Although not every consumer can be bothered to care about wireless power efficiency, government entities certainly are. This is because energy-wasting systems can damage preexisting wireless systems that are deemed essential for public use.

    For the time being,the most efficient long range Qi charging system reaches an 82% RF to DC conversion inside a receiver array. Going forward, this will have to increase considerably without affecting any adjacent wireless systems or posing any sort of public health risk. For now, this method registers considerable losses in the transmitter area for issues related to how transmitters are built.

    To focus solely on the abstract – out of 400 kW transmitted, only 34 kW can be received across medium-to-long-range distances. This means a 7% overall efficiency for a system that will eventually have to go above 80% to have any chance of being implemented. Bear in mind that this efficiency is also subjected to the design and build of the transmitter, which as we pointed out, leaves a lot to be desired.

    Quality at a steep price

    As groundbreaking as such a technology might be, we also have to take cost into consideration before we even begin to discuss implementation and mass production. By most estimates, a wireless charging system with long-range capabilities would cost no less than $900 or more at the moment due to technological limitations.

    Needless to say, no matter how effective and practical a charger may be, you would have a hard time selling it for roughly the same price as an average smartphone. Not to mention the availability and compatibility issues manufacturers would soon run into if they tried to make their devices compatible with such an expensive charger.

    It is simply not practical at the moment to put forward a model that would satisfy everyone’s concerns while still maintaining a low enough acquisition price to justify the investment. That said, the news we’re getting from the likes of Samsung and Huawei makes us think that a more convenient, affordable solution is right around the corner, albeit in a few years or so.

    What the future has in store

    Looking at what the market has to offer right now, we can deduce that once a viable prototype has been developed, it shouldn’t take more than a couple of years for it to reach a global market. There are, however, questions that need to be raised abouta functional long range Qi charging device with widespread compatibility.

    One such question would be: can a functional long-range wireless charger deliver its charge while maintaining acceptable RF exposure levels? And if so, then what are the safety, RFI, and efficiency requirements that such a device would meet? Needless to say, a decent charger would have to meet both efficiency and functional requirements without any practical limitations to speak of.

    For instance, a long-range charger in the true sense of the word would have to reach devices in virtually any position within a specified range even when the device is on the move. You see, the long-range options available to us at the moment require the device to be held stationary in a specific spot inside a room, which can prove quite an inconvenience in a dynamic environment like a modern office.

    Last but not least, a decent long-range wireless charger would have to maintain perfect functionality and deliver its charge regardless of the target device’s casing. It should also work well when said device is near a Wi-Fi adapter, an NFC receiver, mobile phone station, or car electronics of a wide variety.

    For the time being, the Qi standard is alone in proving practical and consumer-friendly, with close to 100 million Qi chargers being sold worldwide. Not just that but it seems that every next-generation device incorporates Qi charging capabilities, which speaks volumes about the reliability that Qi charging delivers.