Paul Reynolds on the State of Long Distance Wireless Charging – The Wireless Solution

Paul Reynolds on the State of Long Distance Wireless Charging

Paul Reynolds


You may have been aware that in our last blog post on CES 2019 we didn’t really delve into any details about distance or RF wireless charging technology, despite the fact that it was particularly popular at the event. The main reason for this is that we don't feel the technology has developed much at all since last year’s CES.

In our blog post "The Many Different Wireless Charging Technologies” from last year we went into details about the likes of Ossia, Energous and Wi-Charge and although still critical, we tried to keep an open mind about the possibilities. But the reality is that these technologies have developed slowly over the past few years and it looks like for the foreseeable future, RF or distance charging will be limited to charging much smaller IoT devices such as headphones, remotes and other similar gadgets.

This is why out of the RF technologies showcased at CES we’re biggest fans of Powercast, because they’ve embraced their IoT niche and have focused on developing a technology that delivers small trickles of RF power over long time periods. As a result, Powercast were able to showcase a real, market ready product in their Nintendo Joy Con chargers.

So how optimistic should we really be about “true wireless charging” and the possibility of charging your smartphone without wires from anywhere in a room? To get to the bottom of this question we interviewed somewhat of an expert on the subject to talk to us about his thoughts on transferring power over the air.

Paul Reynolds is an engineer and entrepreneur who has specialist expertise in ultrasound and was one of the earliest members of uBeam, a startup that claims its technology can provide power over the air via ultrasonic waves. Following disagreements with the CEO on a number of fronts, Paul left uBeam and has since started a blog called "Lies, Damn Lies, and Startup PR" that warns investors about companies like uBeam and Energous, both of whom have generated millions of dollars of upfront investment without ever producing a working prototype.  

So without further ado, here is Paul Reynolds:


The Interview


Us: Paul thank you for agreeing to this interview, tell us a bit about yourself and what motivated you to start your blog.

Paul: First of all thank you for reaching out and giving me an opportunity to have this discussion with you. I’ve been heavily involved in engineering and tech for the last 25 years, predominantly in a variety of applications of ultrasound, from medical imaging and therapy through sensors and non-destructive testing. I’m also very heavily involved in the IEEE, the world’s largest technical engineering society, having been associate Editor in Chief of the ultrasound peer-reviewed journal, and incoming President of the Ultrasound Society (UFFC). Having lived in Silicon Valley for many years, I was very close to startups and joined uBeam, a wireless power company, when it was essentially two people in a garage, and led the development of much of the system for nearly 3 years and the first $25 million or so raised. There are many reasons for starting my blog, but one of them was that I felt that the public were not getting a clear view of what wireless power transfer would and could realistically achieve. It’s highly unusual for someone who has been so senior in a prominent startup to leave without a ‘gag order’, and having an understanding of not just the technology, but the business and marketing side of the industry, I felt I could give a perspective that few others have.


How long do you estimate it will take before we get true wireless charging for smartphones?

If you are looking for multi-meter, as-fast-as-a-wire charging for smartphones then I expect you are going to be waiting a very long time, I simply do not see that happening. Directing energy is limited by the laws of physics, especially if you wish to do so safely and at a reasonable price. Physics makes it difficult and inefficient, but not impossible – however -most of the current methods under development, such as RF and acoustic, all have to eventually face regulatory limits that are there for safety that simply don’t allow enough power to be useful. You can see this starting to be accepted with most of the prominent wireless power companies like Energous now backing away from multi-meter, multi-watt phone charging, and talking “Internet of Things” (IoT) which are small sensors that need a tiny fraction of the power a phone does. You can see companies like Powercast have been active in that area for a while, and have been selling a product that does exactly that with RF. Most of the limiting factors are not things that will drastically improve over time, so unlike what we have been used to seeing with computational power always getting faster and cheaper, we’re getting pretty close already to what multi-meter wireless power charging will ever be able to do.


Which type of technology do you think is going to provide the most practical wireless charging solution in the coming years?

For contact wireless charging of phones, my opinion is that advancements in charge speeds under Qi, combined with improvements in rapid charge, high capacity batteries, will be the most useful, so that you can maybe get a full day’s charge after dropping on a mat for 15 to 30 minutes. I think that all the more likely now Apple has essentially backed Qi and apparently AirPower being imminent. I do not see any of the radiative methods, such as RF or ultrasound, ever being practical for charging phones. Pi Charging have an interesting approach in trying to essentially shape the field that you get with Qi, to extend the range to maybe 30cm or so, and I’m interested to see what they come up with, which makes Qi just a little bit more practical. Wi-Charge are using lasers and are giving demonstrations which are interesting, and have to their credit been much more open than other such companies, but I have concerns about eye safety and have yet to see the data that makes me comfortable there. In the end, nothing will ever be as fast, efficient, safe, and low cost as a wire, but for the forseeable future I see Qi and its variants as really the only realistic alternative.


What piece of advice would you give wireless charging enthusiasts to look out for when assessing the claims of so called “far field” technologies?    

If something sounds too good to be true, it almost certainly is. If you charge at a distance, you have to give up something like charge speed, efficiency, cost, safety, and the further the distance, the more you have to give up. The best advice I can say is that you simply do not believe anything such a company tells you until they have a product that is out, available for purchase, and has been broken open and investigated by third parties – this is a field that is rife with amazing product announcements that never materialize, so believe it when you hold it in your hands. Powercast are a good example of this, you can buy from them, they provide spec sheets for their parts, and they seem to do what they say – but they don’t and won’t charge phones, just IoT scale. Beyond that, this is a very tricky question to answer, as quite simply the technology to do the multi-meter charging is so multi-disciplinary and complex, and touches on regulatory and safety aspects, that unless you’ve spent years in this field, it’s very easy to get lost, or bamboozled by marketers. I try to cover aspects of this in my blog, but when you compare a marketer saying “We’ll charge your phone with our wifi like router” and then I spend three pages breaking down their claims and proving they are not viable, one side has a much more interesting story that is remembered! They’re selling the fantasy we all want, I’m the boring spoilsport, it doesn’t win many friends. One thing I’ll end on, is that companies like Energous trade on NASDAQ for under $200m market cap – if they could truly do what they claim, someone like Apple, Google, or Samsung would have snapped them up at what is for them pocket change.


Our Final Thoughts

Although we’re never ones to criticise innovation and creativity at The Wireless Solution, it’s got to the point where we feel the need to educate people on how some of these startups can manipulate and trick investors out of their money. Issues arise when startups realise they can generate investments without ever producing a physical product. They then use their marketing teams to drum up support for their campaigns and win over investors who have no experience in the industry.

If you don’t believe in the power of marketing just look at some of these headlines below. Over the air wireless charging is heavily marketed as the future because its more revolutionary and a lot “sexier” than your standard inductive charger. But the truth is that there has been no real indication that this technology will be charging our phones anytime soon.  


Headlines from CES 2019


As much as we’d love to be able to charge our phones from across the room and never have to worry about them running out of juice ever again, the reality is that Qi, at least for the foreseeable future, remains the only practical solution to wireless charging.

We highly recommend Paul’s blog post on uBeam at CES 2019 if you want to read more on this topic.

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