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MartinAppleGuy

macrumors 68020
Original poster
Sep 27, 2013
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Is it ok to leave the charging puck on at the wall at all times? Does it draw any electricity when the Apple Watch isn't on it?
 
What do you do with your iPhone charger? Do the same.
Well it gets switched off when not in use, but my Apple Watch is using a socket that is hard to access. I'm just wondering what other people do and if it will draw energy. Boy at the Apple Store said it was fine but just checking.
 
Mine is the same' the socket is located behind a set of heavy bedside drawers. It's been left on permanently for the past 18 months. No issues here.
 
Sure not a problem but it should draw a very little of energy even while not charging

The charging puck has no idea if it is charging a watch or not. It uses the same amount of voltage no matter what so if you are one of those green types, you should unplug it when not in use. Do not forget to unplug those clocks when not looking at them, too.
 
The charging puck has no idea if it is charging a watch or not. It uses the same amount of voltage no matter what so if you are one of those green types, you should unplug it when not in use. Do not forget to unplug those clocks when not looking at them, too.
Can I actually ask a question with such a sarcastic response?
 
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So can the puck/wall charger know of it is to draw energy or not?
As far as I know: if you are charging, you draw the energy used for charging (of course). If you're not chanrging, the transformer inside the charger should draw a little energy, much less than while charging but always present (sorry, I'm not mother language with English)
 
So can the puck/wall charger know of it is to draw energy or not?

No, the puck is creating the same magnetic field no matter if attached to a watch or not. It gets no feedback from the watch.
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As far as I know: if you are charging, you draw the energy used for charging (of course). If you're not chanrging, the transformer inside the charger should draw a little energy, much less than while charging but always present (sorry, I'm not mother language with English)

There is no direct electrical contact between the watch and the charger. The charger uses the same amount of power no matter if it is charging or not. It is not like plugging your phone in, there is no connection to the puck.
 
No, the puck is creating the same magnetic field no matter if attached to a watch or not. It gets no feedback from the watch.
[doublepost=1479905749][/doublepost]

There is no direct electrical contact between the watch and the charger. The charger uses the same amount of power no matter if it is charging or not. It is not like plugging your phone in, there is no connection to the puck.
Are you sure? a transformer has different power draw if he's in use or in idle
 
Are you sure? a transformer has different power draw if he's in use or in idle

Normally that would be correct but not in this case.

The transformer creates the same magnetic field no matter if the watch is there or not. It is different than plugging in something like your iPhone which has a direct electrical connection.

How would the transformer know it has a watch by the puck?
 
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The puck will know because the impedance in the circuit with the watch will change. Yes, it's NOT connected directly to the watch, but the appearance of the watch in the magnetic field and the draw of the watch on the field from the puck will, in fact, show up in the power demand of the puck. Just like the input coils of a transformer do not directly connect to the output coils, when power is taken from the output coils, the input coils see the load change. So the puck, while simply plugged in, will draw a bit of power, but when the watch is attached and charging, the total power use will increase.

All that said, we're talking tiny amounts of power, so I wouldn't worry about it.
 
You can use physics to figure it out. If your charging puck gets warm without a Watch on it, it consumes power.

Energy is conservated in the universe, if it's warm it draws power aka electrical energy gets converted to thermal energy and electromagnetic fields (for the inductive charge). Since it's cold when not with a Watch on it, the logical conclusion is that it only draws power when activated by a Watch.

So go and enjoy more important things in life :) and don't wear out your plugs needlessly
 
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In my experience, maybe it makes a difference of a few pennies a year, not enough for me to even care.

I also leave lightning cables plugged in all the time, I remember reading somewhere that the average total electrical usage of a whole year of using an iPad was $2.
 
You can use physics to figure it out. If your charging puck gets warm without a Watch on it, it consumes power.

Energy is conservated in the universe, if it's warm it draws power aka electrical energy gets converted to thermal energy and electromagnetic fields (for the inductive charge). Since it's cold when not with a Watch on it, the logical conclusion is that it only draws power when activated by a Watch.

So go and enjoy more important things in life :) and don't wear out your plugs needlessly

Interestingly, I checked my charging puck with a Flir thermal imaging camera after the puck had been plugged in overnight without charging a watch. It was clearly warmer than the environment around it.

So, yes, it does in fact continue drawing power constantly.
 
Interestingly, I checked my charging puck with a Flir thermal imaging camera after the puck had been plugged in overnight without charging a watch. It was clearly warmer than the environment around it.

So, yes, it does in fact continue drawing power constantly.

I must admit, you've left me without comment lol. It's still colder by a factor, than with a watch on it. And also it must have a small field that will be disturbed by the watch to trigger full field charging, so it will stay on at some percent.

But still you're looking at (guessing here) 1w per month standby vs 3w per month charging... A single lightbulb is 60w, a kitchen appliance 5w just sitting turned off.

Bottom line, more power is being consumed to manufacture a replacement power socket :p
 
The charging pluck is not dumb.

There is bidirectional communication between the pluck and the watch to negociate, allow, and modulate power ouput.

Qi-wireless standard devices also use the same mechanisms. You just can't put a matching coil and expect the receiver to draw power. It won't happen without authentification.

Regarding the energy savings of unplugging the AC/DC block every day I wouldn't do it. There is an higher probability that the constant mechanical stress will damage either the socket or the transformer which will end up costing much more than the dollar a year you'll save in utility bill.

Also, it's very probable you have much much larger energy wasting habits / devices to eliminate before you start chasing the milliwatts ghosts.
 
You can use physics to figure it out. If your charging puck gets warm without a Watch on it, it consumes power.

Energy is conservated in the universe, if it's warm it draws power aka electrical energy gets converted to thermal energy and electromagnetic fields (for the inductive charge). Since it's cold when not with a Watch on it, the logical conclusion is that it only draws power when activated by a Watch.

So go and enjoy more important things in life :) and don't wear out your plugs needlessly

I am pretty sure it is the battery that is getting warm.
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The charging pluck is not dumb.

There is bidirectional communication between the pluck and the watch to negociate, allow, and modulate power ouput.

If that is so my Oral B wireless toothbrush charger is communicating with my Apple Watch as I can make my Watch chime and go into Charge mode by holding it just right. :p
 
I am pretty sure it is the battery that is getting warm.
[doublepost=1480073355][/doublepost]

If that is so my Oral B wireless toothbrush charger is communicating with my Apple Watch as I can make my Watch chime and go into Charge mode by holding it just right. :p

You know that, you are making us use a lot of electricity, when we reply
 
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I am pretty sure it is the battery that is getting warm.
[doublepost=1480073355][/doublepost]

If that is so my Oral B wireless toothbrush charger is communicating with my Apple Watch as I can make my Watch chime and go into Charge mode by holding it just right. :p

Might light up the watch as it's detecting an em field but I assure you it won't charge as there won't be proper auth.

It's the same the other way round. The AW pluck will wake up the toothbrush but rapidly shut off as the authentification is missing.
 
Sorry man but still thinking the puck is stupid.

I worked on Qi-wireless power transfer designs. Trust me, I'm an engineer :D.

The AW puck has been confirmed to be Qi-compliant and will charge any Qi-certified device *
http://appleinsider.com/articles/15...-compliant-with-qi-wireless-charging-standard

The AW itself is Qi-compliant in principle but an additional layer of proprietary auth restricts it to the official puck.

Similar auth mechanisms are found in Lightning cables. If a 3rd party cable lacks the MFi chip (or use a spoofed one). It will not charge an iDevice (or will for a very short time and then issue an error message)

Qi-standard devices, including the AW, use the following system architecture. Notice the "Communications & Control Unit":

Qi_wireless_power_interface_specification_-_basic_system_overview.png



* electric toothbrushes (Braun Oral-b / Philips Sonicare) don't use Qi, but a fully proprietary design that's one of the oldest large-scale consumer wireless power transfer system in use (15+ years). They don't have any auth / comms module and their implementation can be 100% analogue.
 
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