wireless charging (eg, Qi) - slow adoption?

[linux-works]

how well is Qi being adopted by vendors and consumers?  is this the format that 'won'?  when I search for 'wireless charging' on, say, amazon, I only see Qi results.

I do get lots of results and lots of $10 class charging pads, and also, now, $10-20 credit card insert things that have the receiver chip and coil and either tap into the battery contacts or connect to the micro usb connector via flex pcb.

BUT - when I go out to stores, even here in silicon valley, I don't see much at all for Qi.  went to frys today (pretty big and somewhat famous electronics chain in this area) and they had a samsung charger for $40 and some used POS for $80 (!).  that's it.  radio shack, what is left of them, had the same samsung pad, also $40.  went to an office supply store and the guy knew what I was looking for but almost laughed since its 'too high tech' for an office store (he said).

could not get anything locally.  sure, some phones are now coming with qi coils in them but I'm not seeing pads in the stores and I'm not seeing stores showing much interest, either.

a friend tells me that 'its already a market failure'.  I'm not sure I agree as I kind of like the idea, but when I went out looking for stuff, I found next to nothing.

what's your experience with current product and/or implementing with it?  I'm thinking of trying to use it in a project I'm working on but I'm brand new to this wireless charging stuff.  are there compatibility issues out there?  do all the chips work with each other?  is the standard 'finished' or does it really need more work?  any insight on this would be appreciated.  and if its not all its cracked up to be, I'd also like to hear that before I spend a bit of time and money on it.

[poorchava]

I think wireless charging was not very well received, and but have no idea why. Everyone I know who has used this technology seems very happy with it. For some reason though very few (if any) new devices support it without additional accessories like the aforementioned add-on cases and flst-flex antennas. Silicon vendors have some pretty good solutions. I've even see an TI chipset that they claim can deliver over 10W of power (although this is outside of Qi specification)

Sent from my HTC One M8s using Tapatalk

[electr_peter]

I consider wireless charging to be a niche sector for consumer market. Market failure would be too strong word to describe the situation. It is relatively expensive, advantages show up only under certain conditions (you still need wired charger, wires and base station to use it, charging distance/position has to be exact for it to work at all). Qi is effectively the same as old cell phone/PDA charging docks/stations (device sits in the dock, makes contact and charges) which was not very popular as well.
Also, only the most expensive phones have it built-in, so even less consumers know and would like to use such "flashy toy" like function. I have tried it but do not like it too much - I do not need extra wires and devices consuming space and outlets all the time (I prefer to use charger when needed, otherwise store it in a drawer).

In short - with Qi charging you have to spend additional amount of money just to get very similar result of regular cheap charger, so I just do not see it as a popular technology in a consumer market.

I had issues with cheap Qi transmitters/receivers, but I would consider Qi as an option for some electronics devices where physical separation or "invisibility" of wires is needed. You can build you own custom charger to suit your power/distance/efficiency requirements as well.

[Psi]

I got a random Qi charger for my LG G3.
It doesn't work reliably, it starts charging but always seems to abandon the charge some time later, which makes it useless

I should have got the official LG Qi charger

[saturation]

I experimented with several Qi chargers for a month but even with its current version, the inductive losses were high and lost as heat, being very problematic. 

Passive cooling at 25^oC ambient it would reach 40-50^oC.  In the winter at20^oC ambient, it reached 35-40^oC.  With a fan,  it would hold under 40^oC. 

Transfer efficiency was 70-80% at best, and position sensitive.  If you use a cradle to lock in coils sweet spot instead of a formless pad or platform, it works best.   Alas at worse, my phone would signal OK to its position at 50% efficiency.

I monitored  charger output with a ammeter/power meter and the phone's via a power and temperature monitor app.  I also double checked the temperature via IR thermometer.

Big problems:

My phone has charge temperature protection, and at times the phone terminated charging due to heat rise, further lengthening the charge time, and we are not yet in the peak of summer temperatures.

The battery was never fully charged relative to direct cable charge, even with the phone powered off, and even if the phone signaled full charged in about 6 hours, I left it trickling for a whole day.  At charge termination, the battery would rapidly drop from 100-90% in a 2 quiescent hours.  On an optimal USB charge, it would still register 99%. 

On a USB charge, the phone never exceed 35C with passive cooling.

While I can tolerate the charge inefficiency, in general heat is a killer of batteries.  At over 35^oC, cycle life is reduced [ my projection] , charge retention is reduced [ likely demonstrated, as it never fills completely].   

[mikeselectricstuff]

A problem is that charging is limited to about 500mA, when the norm nowadays is often  2-4x that.

One area it is handy for is charging sealed devices, but you really need a charging cradle that holds everything in good alignment

[amyk]

Having a cable plugged in is better as you can move the device around and otherwise continue using it while it charges.

[fubar.gr]

As already noted, wireless charging is full of drawbacks. It's only good for the uber lazy who can't be arsed to spend half a second to connect a damn cable. Nothing more than a gimmick.

[linux-works]

As already noted, wireless charging is full of drawbacks. It's only good for the uber lazy who can't be arsed to spend half a second to connect a damn cable. Nothing more than a gimmick.

I just got a set of parts to play with (mail just arrived)

at first test, it looks good, actually.  but time will tell.

I bought these to try out:

https://www.amazon.com/gp/product/B00MN3RR7Q

https://www.amazon.com/gp/product/B00HJ2KEMQ

a very low-priced base (which has mixed reviews) and a very low priced receiver coil 'card'.

the card is nice.  it fits perfectly in my ancient android phone and also fits perfectly in my portable audio player.  it does eat up a micro usb port and on my audio player, that is a problem since the usb port can be used for charging as well as OTG usb mem sticks for extra storage.  might see if I can tap into the power leads directly and save the usb port for data.

the pad is big which I like since you don't have to balance the charged device on a tiny little puck.

also tried the adafruit coil unit and that seems to give me exactly 5.00 volts (on my fluke) when I sit it on the charging pad.  here's the adafruit diy card in my hand, for size comparison:



soldering 2 wires to the bottom 2 pads does give me that 5v as it should.

as for being lazy, its not always about that.  samsung, for example, has a known history of their usb ports being somehow different from many cables.  lots of direct experience with this (I used to work at an android tech company and lots of peoples' samsung phones would not charge with micro usb cables that worked for other phones).  the micro usb port is better than mini usb but it still can fail and it does on lots of devices.

wires are annoying.  I converted to a cordless mouse over a decade ago and never went back to a wired mouse.  wired keyboard, ok, but mouse moves around and is natural for wireless.

same with small devices.  I want to be able to pickup and use the phone for a bit but then put it back down and have it resume charging.  why deal with cords when you can pick it up, use it, put it down and there's no tangle?  seems like a total win to me, as long as you are not in a hurry to get the device charged.  if its always left on the pad, its always catching up and at least not draining the battery, as is the usual case when its not connected to a charger of some kind.

I'm going to give this tech a few months testing to see how it works out and what issues I'll find over time.  but so far, I really like the idea, at least.

[linux-works]

A problem is that charging is limited to about 500mA, when the norm nowadays is often  2-4x that.

One area it is handy for is charging sealed devices, but you really need a charging cradle that holds everything in good alignment

if I needed a super fast charge, yes, I'd go wired.  of course.

but if a trickle charge is acceptable, then charge speed is not an issue.  in fact, charging slower is better for the battery in every case.

I do agree about the cradle part and I may build one to work with the device I'm designing.  that way they are aligned together by design.  so far, though, the 2 pads I bought are not critical about alignment and I'm able to see the device immediately go into charge mode, not even caring what the base's light has to say.

[Sigmoid]

I think wireless charging was not very well received, and but have no idea why. Everyone I know who has used this technology seems very happy with it.

If the first thing you can think of about a new technology is "it's cool but... why?", then it's kinda doomed. Why would I want wireless charging? It's quite thoroughly pointless. And do I want even more EM radiation in my living space?

[nctnico]

I think wireless charging was not very well received, and but have no idea why. Everyone I know who has used this technology seems very happy with it.

If the first thing you can think of about a new technology is "it's cool but... why?", then it's kinda doomed. Why would I want wireless charging? It's quite thoroughly pointless. And do I want even more EM radiation in my living space?

Those are good questions. IMHO the Qi standard is rather over engineered (as usual) and the power levels are very low. What I'm seeing is that wireless power is very interesting for applications which (for example) need a high voltage isolation barrier (tens of kV) or cannot use connectors (under water). However in those situations a full Qi implementation is just overkill and the required power levels are usually much higher.

[Psi]

The thing that annoys me is that once the phone gives up on the Qi recharge a few times it doesn't seem to try again until you remove it and put it back down.

So you put it on the charge pad and it begins charging just fine, then a few min/hours later while you're asleep it decides to abort charging and you wake up with a phone that isn't full.

[andtfoot]

The thing that annoys me is that once the phone gives up on the Qi recharge a few times it doesn't seem to try again until you remove it and put it back down.

So you put it on the charge pad and it begins charging just fine, then a few min/hours later while you're asleep it decides to abort charging and you wake up with a phone that isn't full.

I can't say I've ever that issue. I'm using a Nokia Lumia 930 and Nokia charging pads.

I have a charger at home and at work; I find it handy to able to just drop the phone on the pad when I sit down, and grab it when getting up to walk away.
I've never had to resort to charging from the cable, unless I'm interstate or something (where I charge from my laptop I have with me anyway).

[Psi]

maybe its just my crappy 3rd party Qi charger

[mikeselectricstuff]

Incidentally if you want to add Qi charging to your product without the gamble of using no-name Chinese receivers, TDK do an OEM module :
http://www.digikey.co.uk/product-detail/en/WRM483245-15F5-5V-G/445-16097-ND/4702663

[EEVblog]

Everyone is waiting for uBeam 

[Galenbo]

Could be a good thing for dust/waterproof devices. On my S7710, like on every other S7710 phone, the rubber dust/water cap broke off after some weeks.

[andtfoot]

Everyone is waiting for uBeam 

[zapta]

Conductive wire free bases can provide higher power and at higher efficiency

http://www.pcmag.com/article2/0,2817,743234,00.asp

http://www.gizmag.com/review-wildcharge-wireless-power/13186/

[Gribo]

My experience with Qi chargers: Most are crap, the ones that use the IDT chipset are the worst. The better ones use the TI chipset and reference design, along with a decent coil, however, most OEM don't bother tuning them for maximum performance. The same happens with the receiver, TI based devices have generally better user experience than IDT based devices, and on the receiver, tuning is far more critical.

[Mr.B]

As already noted, wireless charging is full of drawbacks. It's only good for the uber lazy who can't be arsed to spend half a second to connect a damn cable. Nothing more than a gimmick.

I totally disagree...
I am not lazy and it is not a gimmick to me.
I have a Samsung Galaxy S6.
I have a genuine Samsung Qi charger base for it.
Before I go to bed at night, I simply drop it on the pad as I send the dogs off to bed.
I don't need to pay particular attention to alignment... somewhere in the middle is good enough.
Next morning I have a full battery ready to go for the day...
Great concept as far as i am concerned.

Oh, and by the way, my micro usb socket will not wear out as I don't plug it in every night...

[Jeroen3]

There are two scenarios where wireless charging becomes interesting imho.
- Fully enclosed waterproof devices. Such as diving gear, smartwatches and waterproof phones. (Why do you even need a waterproof phone? For "entertainment" in the shower?)
- Batteries that charge in a few minutes. Just put the device on the charge pad for a few minutes and it's fully charged.

Where wireless charging does not have any direct benefit on your nightstand. The device has the full night (5+ hours, for most people) to charge. Wireless will only introduce unnecessary loss. And unnecessary electromagnetic interference of which we still aren't 100% sure it's safe for humans. Also, unconnected phone chargers cause enough standby load to have a significant accumulated loss. Wireless charges will only make this worse.

It might also be of interest in things that have to recharge A LOT of times. Such as in-flight entertainment pads. Or Lasergame backpacks.
But it is financially more interesting to swap the battery-pack.

[Sigmoid]

I totally disagree...
I am not lazy and it is not a gimmick to me.
I have a Samsung Galaxy S6.
I have a genuine Samsung Qi charger base for it.
Before I go to bed at night, I simply drop it on the pad as I send the dogs off to bed.
I don't need to pay particular attention to alignment... somewhere in the middle is good enough.
Next morning I have a full battery ready to go for the day...
Great concept as far as i am concerned.

Oh, and by the way, my micro usb socket will not wear out as I don't plug it in every night...

I have an iPhone and a wall charger.
Before I go to bed at night, I simply plug in the Lightning conenctor and send the dogs off to bed.
I don't need to pay particular attention to alignment, Lightning is robust and reversible.
Next morning I have a full battery ready to go for the day.

Oh and by the way, Lightning was designed to be plugged in every night, so it doesn't wear out.

As a HUGE plus, I don't need a "base station" at all, and if I want to plug the phone in somewhere else, I only need to take the wall charger, which is so small and light it practically disappears in my pocket.

[zapta]

As a HUGE plus, I don't need a "base station" at all, and if I want to plug the phone in somewhere else, I only need to take the wall charger, which is so small and light it practically disappears in my pocket.

The promise of wirefree charging surfaces is that they will be universal and ubiquitous. That is, charge any device and available everywhere, homes, cars, offices, coffee shops, hotels, airports, etc, often embedded in furniture and large enough to power multiple devices. If and when this will happen, and this is a big if, you will not need to carry anything.