An open community 
of Macintosh users,
for Macintosh users.

FineTunedMac Dashboard widget now available! Download Here

Topic Options
#48106 - 03/04/18 03:12 AM Wireless Charging Speeds & Harm
Pendragon Offline


Registered: 08/04/09
Loc: Georgetown, Texas, USA
“The faster 12W & 15W wireless chargers are more likely to harm or not charge your device as well as the slower 7.5W chargers”.

Is that merely an old wife’s tale or is there substance in that counsel? confused
_________________________
Harv
27" i7 iMac (10.13.6), iPhone Xs Max (12.1)

Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

Top
#48107 - 03/04/18 03:54 AM Re: Wireless Charging Speeds & Harm [Re: Pendragon]
Urquhart Offline


Registered: 08/10/17
Loc: Netherlands
[citation needed] wink

AFAIK, the thing to look out for is heat, which could do damage/shorten the lifespan. If the charger or device get very hot for a long time, then that will have to be dealt with.

Top
#48108 - 03/04/18 04:49 AM Re: Wireless Charging Speeds & Harm [Re: Urquhart]
Pendragon Offline


Registered: 08/04/09
Loc: Georgetown, Texas, USA
When you mention heat shortening the life span, you are referring to the device and not the charger?

FWIW, the new Mophie 7.5 charger I was given always remains cool. The charger in my new Honda gets quite warm. I'll call Honda and see what they say re the charging specs.
_________________________
Harv
27" i7 iMac (10.13.6), iPhone Xs Max (12.1)

Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

Top
#48109 - 03/04/18 05:30 AM Re: Wireless Charging Speeds & Harm [Re: Pendragon]
joemikeb Online
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Most Q1 wireless chargers have heat sensors and will shut down if either the charger or the device being charged get too hot. Unfortunately finding out whether a particular charger is so equipped can be very difficult.

NOTE: I have seen test results on MacRumors, 9to5Mac, or Apple Insider (I don't remember which) that found the so called fast chargers are not significantly faster than the standard wireless chargers and by far the fastest way to charge an iPhone X is with the 12W power adaptor and a lightning cable. Even the 5W power adaptor with a lightning cable charges the iPhone faster than a wireless charger at any power level.
_________________________
joemikeb • moderator

Top
#48110 - 03/04/18 06:08 AM Re: Wireless Charging Speeds & Harm [Re: joemikeb]
Pendragon Offline


Registered: 08/04/09
Loc: Georgetown, Texas, USA
Originally Posted By: joemikeb
Most Q1 wireless chargers have heat sensors and will shut down if either the charger or the device being charged get too hot. Unfortunately finding out whether a particular charger is so equipped can be very difficult.

NOTE: I have seen test results on MacRumors, 9to5Mac, or Apple Insider (I don't remember which) that found the so called fast chargers are not significantly faster than the standard wireless chargers and by far the fastest way to charge an iPhone X is with the 12W power adaptor and a lightning cable. Even the 5W power adaptor with a lightning cable charges the iPhone faster than a wireless charger at any power level.


Now that is interesting, i.e. the fastest charge can be obtained using (both), wired and wireless simultaneously.
_________________________
Harv
27" i7 iMac (10.13.6), iPhone Xs Max (12.1)

Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

Top
#48112 - 03/04/18 08:57 AM Re: Wireless Charging Speeds & Harm [Re: Pendragon]
alternaut Offline

Moderator

Registered: 08/04/09
In addition to the charger type used, the specific type of USB-C connection involved may be of influence. For charging purposes, the presence (or absence) of a PD (Power Delivery) controller chip is important. Check out David Luckhardt’s comments (and following) on the topic. And yes, this may be more of an issue with wired chargers, but not exclusively so.
_________________________
alternaut moderator

Top
#48114 - 03/04/18 12:00 PM Re: Wireless Charging Speeds & Harm [Re: Pendragon]
joemikeb Online
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Originally Posted By: Pendragon
Now that is interesting, i.e. the fastest charge can be obtained using (both), wired and wireless simultaneously.

You misunderstood what I said.
  • There was no test conducted with both wired and wireless charging simultaneously.
  • The fastest charging was wired using the 12W power adaptor that comes with an iPad attached to the iPhone with a lightning cable.
  • the 5W wired charger that comes in the box with an iPhone was second fastest
  • The wireless fast chargers (15W) were only marginally faster than the lower powered wireless chargers.
The author's conclusion was wireless chargers are more convenient than wired chargers, but if you want the fastest charge go with the 12W power adapter that comes with an iPad and a lightning cable.

My personal choice is to use a wireless charger because it is so convenient and I am seldom, if ever, in a hurry to charge my iPhone. Since most Qi plates do not come with their own power adaptor I use an Anker PowerPort Wireless 10 Qi certified wireless charging pad connected to an Apple 12W USB power adaptor I happened to have lying around the house. I chose the Anker plate because many other Qi power plates have bright LEDs which are really annoying on my bedside table and the LEDs on the Anker blink on and off for about five seconds to indicate the iPhone is properly placed and then go off and stay off. I just checked the label on my Qi power plate and with a 5V input the output is rated at 1W, with a 9V input the output increases to a whopping 1.1W which would appear to validate the test findings that the fast chargers are only very slightly faster.
_________________________
joemikeb • moderator

Top
#48115 - 03/04/18 12:16 PM Re: Wireless Charging Speeds & Harm [Re: joemikeb]
Pendragon Offline


Registered: 08/04/09
Loc: Georgetown, Texas, USA
Joe,

Thanks for straightening me out. Indeed I thought using both simultaneously was illogical, but then, there is much in the relhm of batteries, electrons, ions, and such that I just don't "get". Even the concept of wireless charging is still magic to me...
_________________________
Harv
27" i7 iMac (10.13.6), iPhone Xs Max (12.1)

Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

Top
#48117 - 03/04/18 12:44 PM Re: Wireless Charging Speeds & Harm [Re: joemikeb]
ryck Offline


Registered: 08/04/09
Loc: Okanagan Valley
Originally Posted By: joemikeb
Most Q1 wireless chargers have heat sensors and will shut down if either the charger or the device being charged get too hot. Unfortunately finding out whether a particular charger is so equipped can be very difficult.

Perhaps it can also have catastrophic results. Here is a case where it appears something got too hot from the charging process.


Edited by ryck (03/04/18 12:46 PM)
_________________________
ryck

iMac (Retina 5K, 27", 2017), 3.4 GHz Intel Core i5, 8GB RAM, 2400 MHz DDR4
OS High Sierra 10.13.6
Canon MX712 Printer
Epson Perfection V500 Photo Scanner
Time Machine on 320GB OWC Mercury OTG Pro
Super Duper on 500GB OWC Mercury OTG Pro

Top
#48144 - 03/06/18 06:56 AM Re: Wireless Charging Speeds & Harm [Re: ryck]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Originally Posted By: ryck
Perhaps it can also have catastrophic results. Here is a case where it appears something got too hot from the charging process.

Most device manufacturers caution you to not leave a charging device unattended. I wonder if Apple has that clause written down anywhere that I've agreed to?

I know I personally don't leave charging stuff unattended. Closest I get to that is sometimes leaving my phone charging when I go to bed. But then again I'm home and I have smoke detectors. I would never leave a phone home alone on charge.
_________________________
I work for the Department of Redundancy Department

Top
#48146 - 03/06/18 08:01 AM Re: Wireless Charging Speeds & Harm [Re: Virtual1]
joemikeb Online
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
This statement from the Wireless Power Consortium addresses safety as a key issue in certification testing. It would appear Qi certification should allay any overheating concerns. Unfortunately there are apparently a LOT of uncertified chargers on the market.
_________________________
joemikeb • moderator

Top
#48181 - 03/08/18 09:53 AM Re: Wireless Charging Speeds & Harm [Re: joemikeb]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
also a few things to note:

(1) current (and in the case where voltage is constant, this also includes power aka watts) is supplied on demand, where the peripheral being powered or charged is making the demands. So electrically speaking, a device that "demands" 7 watts of power won't care if the power supply is capable[i/] of producing 12 watts. or 20. or 500. The supply will only be able to provide what the accessory demands. A power supply with a much larger than necessary capacity is absolutely NO risk to anyone. This is a common misconception, I run into people from time to time that think you can't safely plug a 20 watt accessory into a 50 watt power supply "because the power supply is too big and will fry the accessory". That's not how electricity works.

(2) if the accessory demands more power than the power supply can safely provide, there are several possible outcomes:
A- the power supply may detect the excessive demand and just plain SHUT OFF completely (best option for a good "smart" supply)
B- the power supply may "sag" and lower the output voltage. Power supplies have a limited output power, in watts, and watts is volts x amps, so if the accessory is supplying too many amps (at the designed volts) then all the supply can do is shut off (A) or drop the volts so volts x amps is at or below the supply's ability to deliver the watts. "intelligent" accessories will notice the sag, stop charging, and display a warning on their display (if they have one) to indicate there is a problem with the supply.
C- the power supply may blindly continue to provide as much power as it can (often with some amount of sag) but since they are handing more than their rated power, they will overheat, which may trigger them to automatically shut down, smoke and die, or catch fire. This doesn't usually damage the accessory [i]electrically
, but the fire may be a bigger concern.

So if the power supply is dumb AND the accessory is dumb, it may result in dead, smoking, or flammable power supplies.

Anytime a peripheral (like a phone left on charge) is overheating or catching on fire is ENTIRELY a problem with the accessory, not the power supply. All accessories should be expected to keep an eye on voltage and current levels and cease their demand on the power supply if they notice a problem.


None of this changes when switching from wired to contactless charging.


Somewhat recently USB standards were updated to allow power supplies to notify accessories (cheaply) how much power they could supply, which allowed accessories to adjust their demands based on what the power supply claimed to support. Many newer devices (iPhones for example) will refuse to charge at all (make no demand) if plugged into a supply that doesn't provide this information, "because they don't know how much power they can safely draw". You will see an error message on your iPhone when attaching to a "dumb charger". This does not prevent a dumb accessory from still trying to demand more than the power supply can provide, and all of the above rules will always remain in effect.

This also does not stop scrupulous manufacturers from rigging their power supplies to indicate they can provide more power than they are able to safely produce on a continuous basis. This is generally where we see charger fires nowadays. Cheap chargers from China that are rated on the package and over the USB to supply 10 watts (2 amps at 5 volts) but that can only supply, for example, 5 watts continuous, or 7 watts for a short time (with a sag down to 4.8 volts) or 10 watts with significant sag (4.2 volts?) for a few minutes, before overheating and possibly igniting.



_________________________
I work for the Department of Redundancy Department

Top

Moderator:  alternaut, cyn