max2

macrumors 601
Original poster
May 31, 2015
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Why does the Apple Pencil charge faster when directly plugged into a iPad Pro ?
 

Puonti

macrumors 65816
Mar 14, 2011
1,195
754
What kind of charger do you use to charge it when you don’t want to plug it directly into an iPad Pro? And which iPad Pro do you use it with?
 

max2

macrumors 601
Original poster
May 31, 2015
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What kind of charger do you use to charge it when you don’t want to plug it directly into an iPad Pro? And which iPad Pro do you use it with?

The cable and included little adapter.
 

TinyChip

macrumors regular
Sep 19, 2015
166
100
California
The charger that comes with iPad Pro is rated at 12W. Are you sure you are not using the little 5W charger that comes with the iPhones?
 

Puonti

macrumors 65816
Mar 14, 2011
1,195
754
Well, this is just theoretical thinking and I can’t back any of this up, but since the 10.5” and 12.9” inch iPads Pro support fast charging (29W), it’s possible their Lightning ports are also able to provide more power to compatible products like the Apple Pencil than the standard 12W iPad charger. The fast charging is based on USB Power Delivery which I imagine can go either way.

If you have the 9.7” iPad Pro, though, then even this flimsy theory doesn’t apply since it doesn’t support USB-PD fast charging.
 
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max2

macrumors 601
Original poster
May 31, 2015
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Well, this is just theoretical thinking and I can’t back any of this up, but since the 10.5” and 12.9” inch iPads Pro support fast charging (29W), it’s possible their Lightning ports are also able to provide more power to compatible products like the Apple Pencil than the standard 12W iPad charger. The fast charging is based on USB Power Delivery which I imagine can go either way.

If you have the 9.7” iPad Pro, though, then even this flimsy theory doesn’t apply since it doesn’t support USB-PD fast charging.

Thanks this is true!
 

GrindedDown

macrumors 6502a
Jun 4, 2009
641
206
Las Vegas
So I have an idea as to what may be going on. See on typical lighting cables, there are only one set of power terminals even though the cable is reversible. These +- contact points are wired together. This would be why a standard lightning cabled won’t fast charge the iPad, even with higher powered adapters.

With the usb-c to lightning cable and the apple pencil, I believe these + and - terminals on each side of the lightning cable are NOT connected. Instead, what is happening is that you have two concurrent power lines. The ipad has this same power output capability built into it’s lightning port (two separate + and - terminals). Since these devices carry multiple cells, what is happening is that each power line (1 on each side of lightning connector and port on ipad) is I/O’ing the maximum USB spec to each line, resulting in double the power.

I don’t know if that made any sense, but if it does, I believe that is what is going on.
 

max2

macrumors 601
Original poster
May 31, 2015
4,421
996
So I have an idea as to what may be going on. See on typical lighting cables, there are only one set of power terminals even though the cable is reversible. These +- contact points are wired together. This would be why a standard lightning cabled won’t fast charge the iPad, even with higher powered adapters.

With the usb-c to lightning cable and the apple pencil, I believe these + and - terminals on each side of the lightning cable are NOT connected. Instead, what is happening is that you have two concurrent power lines. The ipad has this same power output capability built into it’s lightning port (two separate + and - terminals). Since these devices carry multiple cells, what is happening is that each power line (1 on each side of lightning connector and port on ipad) is I/O’ing the maximum USB spec to each line, resulting in double the power.

I don’t know if that made any sense, but if it does, I believe that is what is going on.

Makes perfect sense. Thanks!
 
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