Wireless charging in the mobile space has seen its debut almost 6 years ago now with the introduction of the Palm Touchstone. Back in the day, this was quite a revolutionary advancement for mobile devices and I still remember the discussion on how wireless charging would be the future. Six years later, I have yet to own a wireless charger or know somebody who uses one. Analyst prediction of quick adoption failed to materialize and the industry is still trying to consolidate a universal charging standard that would be compatible across all devices. While Palm sparked the wireless charging wars back in 2009, it took device manufacturers many more years before we reached (or have yet to reach) a level of adoption such that the average consumer would be able to confidently use the technology as a de-facto everyday way of charging their devices in the same way that microUSB has.

With the advent of Qi and PMA as opposing and incompatible charger technologies the industry saw a period of uncertainty over which standard would finally make it into the mainstream. In the end, it might be neither, but before we delve into the future, let’s have a look at how wireless charging has evolved over the last few years and how the mechanisms actually work.

A Timeline of Events and Standards

While Palm was first to introduce a wireless charger in the Palm Pre in form of the Touchstone, this was a proprietary standard which wasn’t adopted by other vendors. In fact, while Palm announced and presented the Touchstone at CES 2009, a small group of manufacturers including Logitech, Philips, Sanyo and Texas Instruments gathered around in December of 2008 to form the Wireless Power Consortium, or WPC.

The WPC released later in 2009 the first specification the Qi 1.0 which would become the first proper open wireless charging standard for low power devices. “Qi”, pronounced “chee”, is named after the same Chinese word for “life force” or “energy flow”. In the following months and years the WPC saw a lot of companies adopt the standard and join as members of the consortium. The big names such as LG, Motorola, HTC, Samsung, Sony and Nokia were on board and at this point it looked like Qi was on its way to become the de-facto standard for large scale adoption.

The Nokia Lumia 820 and 920, and more importantly the Nexus 4 were the first devices which introduced Qi charging built-in by default by the manufacturers and were available towards the end of 2012. The biggest enabler of wireless charging though was probably Samsung – starting with the Galaxy S3, Samsung integrated wireless charging capability into their PMICs and exposed on the back of the phones not only pins for the charger coils, but also power contacts which we’ll come back to later. Cheap charger coils that could be added between the battery and cover and attached to the wireless charging pins meant that users could quickly experience wireless charging without too great of an investment.

While the WPC seemed to have won the standards-race with an early start and rising adoption in 2012, the same year the Power Matters Alliance (PMA) was formed as a competing standard. While the WPC seems to have concentrated in the mobile space, the PMA aims to be a more generic standard for other use-cases. Starbuck’s June 2014 announcement of the adoption of PMA notoriously surprised consumers as PMA had seen very little adoption by the market versus Qi. PMA seems to continue to gain adoption by sheer brute force introduction of North American outlets such as McDonalds and Starbucks but faced the problem of needing special charging adapters as no device was yet compatible with the new standard.

While both the WPC and PMA make use of inductive charging technology, a third standard appeared in early 2012 in the form of “Rezence”. The standard is developed by the Alliance for Wireless Power (A4WP). Here the power transfer technology is based on magnetic resonance instead of electromagnetic induction. Rezence sees support of some big companies such as Intel, Broadcom, Qualcomm and Samsung and promises a true alternative to induction charging that solves many of the problems faced with Qi and Powermat (PMA) solutions.

In January 2015 things were shook up again as the PMA and A4WP announced a merger of the two alliances. The merger aims to consolidate the swath of charging standards. While the merger won’t be finalized until June 30th 2015 and things could still change till then, what this means in practice is that Rezence will be seeing a much faster and larger adoption than anticipated through boost of PMA members.

At the time of writing the A4WP has a published 122 members, PMA 68 and the WPC 213 companies.

While Rezence seems to be the most promising candidate technology-wise to being adopted as the “USB of wireless charging” in the distant future, equipment manufacturers will first see the introduction of dual-and tri-standard compatible devices. The Galaxy S6 was one of the first devices to include both Qi and Powermat compatible charging built-in, it still lacks Rezence charging capability. What I expect for future devices though is cross-standard compatibility with help of adoption of solutions which support both inductive and resonance charging.

At MWC 2015 we’ve seen the demonstration of a slew of such solutions by for example MediaTek, Broadcomm and others. It is clear that manufacturers are going for multi-standard compliant end-devices in the future, and it’s the ecosystem around the charging stations which will decide on how things will evolve in the future.

Inductive Coupling - The Basics
Comments Locked


View All Comments

  • fokka - Thursday, April 2, 2015 - link

    you can get wireless chargers for 10 bucks, it's not really a big investment, if you like that convenience.
  • khanikun - Thursday, April 2, 2015 - link

    For me, it's a big hassle to plug in the cord. I have the Xperia Z2, so I have to open up the waterproof door to be able to plug in. Repeated opening/closing of the door messes up the seal. I've had to clean out the door multiple times now to allow it to properly close and seal.

    Luckily, Sony built a magnetic charging plug location. So I just bought the charging dock. Dock the phone, watch it charge. No need to open the door, except when I want to transfer files to the phone.

    Now if wireless charging took off and was standardized, I could see being useful. Like airports, airports, coffee shops, etc having charging locations build into tables and such. You just swing by, plop your phone down, grab a charge without getting into your bag to find your charger.

    Use at home? I'd like it. My phone stops charging anyways, if I grab the phone off the dock. So wouldn't be much change for me.

    Obviously, not everyone wants or needs it, but having the option is nice.
  • Dorek - Thursday, April 2, 2015 - link

    "I charge my phone in no less than 4 unique locations."

    Maybe your money would have been better-spent on a phone with a battery that lasts more than 2 hours?
  • bznotins - Thursday, April 2, 2015 - link

    Maybe I'm one of the few, but I love having wireless charging for my N5 and N7. Not having to fumble with plugs on my nightstand is great, and I have rigged a Nexus charger to a Mountek NGroove mount in my car so that my N5 affixes magnetically to the charger. Thus I have one-touch mounting and charging in my car. Very convenient.

    I get that it's not for everyone, but I quite like it.
  • fokka - Thursday, April 2, 2015 - link

    i didn't have the chance to try it out myself yet, but i would consider wireless charging a big plus in a mobile phone. you don't have to use it, but it doesn't take up much space, it doesn't add much cost, so why not make it a standard?

    i'd love to simply lay my phone down on a mat or put it on a wireless charging stand and being able to just pick it up without fiddling around with any cables or physical connectors. charging might be slower and less efficient, but i don't really care about fast charging when the phone sits on the mat half of the day anyways.
    efficiency is a better point imho, but with the miniscule amount of power a phone needs, that doesn't amount to anything substantial, on a personal basis. turn down the AC just 0.1°C and you're saving tons more than a wireless charger could ever cost you.
  • Cinnabuns - Thursday, April 2, 2015 - link

    I thought the same as you when I got a wireless charger for my Nexus 4. But as I found out the hard way, the bigger issue is how quickly the inefficiency (extra heat) from wireless charging saps the battery's capacity. Wireless charging is probably OK if you're fine with replacing your battery somewhat regularly, but then that's another thing that goes to waste.

    Not to totally rehash an earlier post, but I ended up in a situation where I had 1 N4 charged wirelessly and my wife and another N4 charged via USB. My N4 had half the battery life as my wife's at the end of 2 years.
  • simard57 - Monday, April 6, 2015 - link

    can you elaborate on your Mountek adaption?
    I would like to do something similar but unsure what needs to be done. do you have a "How-to" published - perhaps through the Mountek site?

    I emailed them asking if they have any plans and they said none at this time
  • shadarlo - Thursday, April 2, 2015 - link

    I got a wireless charger for a couple bucks as a test to see how I liked it. I surprisingly don't really like it at all.

    1. The device gets MUCH hotter.
    2. I can't pick the device up to respond to a text, look at the time, etc without it stopping the charge... this is something I can easily do with the traditional cable method.
    3. I have to make sure I place it just right on the charger or it doesn't always charge, so I don't really save much if any time which is often touted as the main benefit.
    4. It charges slower.

    #2 and #4 swap back and forth as my largest annoyances with the tech... the other two issues are minor in comparison.
  • fokka - Thursday, April 2, 2015 - link

    your prioritization is interesting. i wouldn't care much about slower charging, because wireless charging would mean i just place it on the pad whenever i'm not using it, so it's mostly charged anyways when i take it off the charger.

    and why would i care if it stops charging when i take it off the charger for a couple seconds/minutes? i'll place it right back anyways when i'm done.

    i on the other hand wouldn't want my phone to get hot on a regular basis, just because it's charging because that means two things: wasted energy and the battery degrades faster in warm climates.

    and having to place it just right on the charger is a downer too, because it's a slight hassle when using it and setting it down again.
  • shadarlo - Thursday, April 2, 2015 - link

    Ok, so here's a situation.

    You're out all day long and your phone is at 10% and fading fast but you're in the middle of a conversation or need to continue using your phone to look up information, text, etc.

    Wireless charging fails you totally. With a wire you just plug it in and keep working, with wireless you have to set it down and basically stop using it or lean all over the top of it to use it still.

    And slow charging is an issue for the same reason. You come home at 10%, need as much of a charge as possible before heading back out in 30 minutes... every last % matters. If phones had batteries that lasted days then you're right, this wouldn't be much of an issue... but they don't, most batteries last 5-10 hours, especially after a year or two of use.

    The other two issues are annoyances, those two can be total deal breakers that leave the phone unable to be used.

Log in

Don't have an account? Sign up now