12W Power Adapter (20% faster charge)

Bheleu

macrumors 6502
Original poster
Nov 16, 2010
349
1
New on the AppleStore:
http://store.apple.com/us/product/M...er?fnode=48&fs=m.iphoneCompatibility=iphone_5

Comes with the iPad 4th Gen. At 12W instead of 10W, expect a 20% faster charge rate. Unknown if it takes a lightning cable to get the full 12W of power or if an iPad 3rd Gen will use the additional power.

Currently 10W will barely keep an iPad 3 happy and in some instances continue to drop in power if running intense gaming at max brightness.
 

ZipZap

macrumors 603
Dec 14, 2007
5,482
905
New on the AppleStore:
http://store.apple.com/us/product/M...er?fnode=48&fs=m.iphoneCompatibility=iphone_5

Comes with the iPad 4th Gen. At 12W instead of 10W, expect a 20% faster charge rate. Unknown if it takes a lightning cable to get the full 12W of power or if an iPad 3rd Gen will use the additional power.

Currently 10W will barely keep an iPad 3 happy and in some instances continue to drop in power if running intense gaming at max brightness.
Its not the charger that matters is the device's charging hardware and software.
 

dasx

macrumors 65816
Jun 18, 2012
1,098
17
Barcelona
Correct me if I'm wrong but they don't state anywhere that charging times will be a 20% faster.
 

TroyBoy30

macrumors 68020
Jun 9, 2009
2,289
913
Atlanta GA
Never noticed any issues with charging my 3rd gen. I plug it in when I go to bed and its charged when I get up even when it was completely dead.
 

GrandPhrase

macrumors 6502
Jun 16, 2012
432
1
Correct me if I'm wrong but they don't state anywhere that charging times will be a 20% faster.
I believe he stated so because 12W is a 20% increase from 10W. Not sure if the proportion of increase wattage to charging rate is linear, but I believe those were his thoughts.

----------

Will the 12W adapter charge the iPad 3rd generation at a faster rate or will it only affect the iPad 4th generation?
 

w00t951

macrumors 68000
Jan 6, 2009
1,831
6
Pittsburgh, PA
Device charging is regulated entirely from the device. According to the laws of thermodynamics, increasing the rate of charge also exponentially increases heat output (and therefore lowers efficiency). I guess Apple might allow the iPad 4 to charge a bit faster, but nowhere near 20% as the OP suggested.
 

GrandPhrase

macrumors 6502
Jun 16, 2012
432
1
Device charging is regulated entirely from the device. According to the laws of thermodynamics, increasing the rate of charge also exponentially increases heat output (and therefore lowers efficiency). I guess Apple might allow the iPad 4 to charge a bit faster, but nowhere near 20% as the OP suggested.
So the faster charging from the 12W only affects the 4th Gen iPad and not the 3rd Gen iPad, correct (as you stated device charging is regulated from the device)?
 

dasx

macrumors 65816
Jun 18, 2012
1,098
17
Barcelona
I believe he stated so because 12W is a 20% increase from 10W. Not sure if the proportion of increase wattage to charging rate is linear, but I believe those were his thoughts.

----------

Will the 12W adapter charge the iPad 3rd generation at a faster rate or will it only affect the iPad 4th generation?
He's doing the math based on battery charging scaling in a linear fashion.
My point exactly. A 12W charger doesn't necessarily imply that charging times will be a 20% faster. The iDevice can only handle a certain input and it's itself who manages that input.

From my experience, the iPad charger seems to charge the iPhone a bit faster than the regular iPhone charger, so this new 12W adapter might as well decrease a little bit charging times, but we can't say it's gonna be a 20% faster cause it could even be slower (not probable scenario, lol).
 

Bheleu

macrumors 6502
Original poster
Nov 16, 2010
349
1
My point exactly. A 12W charger doesn't necessarily imply that charging times will be a 20% faster. The iDevice can only handle a certain input and it's itself who manages that input.

From my experience, the iPad charger seems to charge the iPhone a bit faster than the regular iPhone charger, so this new 12W adapter might as well decrease a little bit charging times, but we can't say it's gonna be a 20% faster cause it could even be slower (not probable scenario, lol).
The outer two USB pins are power pins. The inner two USB pins are data pins. Unknown is how they handle battery management and if they utilize the data pins while charging batteries, or use these pins to identify the capabilities of the attached Apple brick. If they do use the data pins to manage current rate with the charger, and if it is part of iOS firmware, etc. the iPad 3 may still take advantage of the increased power capability of the charger. It just depends upon how Apple has designed the battery management system.

For instance, increasing the charge rate would increase the temperature of the device itself as it charges. Apple may have it such that it reduces the rate of charge if a temp sensor gets too hot. It may also have a default for what it can charge at. I know when I use a cheap charger, or if my wife uses a charger with her screen brightness set to max she has charge issues where it will not recognize the charger - so I have no doubt that Apple has some "smarts" built into the charging system.

The 20% increase is additional power that is available from the power brick.

5VDC is USB Voltage so instead of 2.0A with a 10W charger; thereoretically if it pulls the maximum current it can now go up to 2.4A during its max charge cycle. When the battery gets to peak charge, typically most battery management systems go into a trickle charge (where it gives it less current).

Power = Voltage * Current

I was going to get one the other day, but the Apple store only had 10W chargers on the shelf. The assoicate was not aware of the new adapter, but he was interested in finding out about it.
 

dasx

macrumors 65816
Jun 18, 2012
1,098
17
Barcelona
The outer two USB pins are power pins. The inner two USB pins are data pins. Unknown is how they handle battery management and if they utilize the data pins while charging batteries, or use these pins to identify the capabilities of the attached Apple brick. If they do use the data pins to manage current rate with the charger, and if it is part of iOS firmware, etc. the iPad 3 may still take advantage of the increased power capability of the charger. It just depends upon how Apple has designed the battery management system.

For instance, increasing the charge rate would increase the temperature of the device itself as it charges. Apple may have it such that it reduces the rate of charge if a temp sensor gets too hot. It may also have a default for what it can charge at. I know when I use a cheap charger, or if my wife uses a charger with her screen brightness set to max she has charge issues where it will not recognize the charger - so I have no doubt that Apple has some "smarts" built into the charging system.

The 20% increase is additional power that is available from the power brick.

5VDC is USB Voltage so instead of 2.0A with a 10W charger; thereoretically if it pulls the maximum current it can now go up to 2.4A during its max charge cycle. When the battery gets to peak charge, typically most battery management systems go into a trickle charge (where it gives it less current).

Power = Voltage * Current

I was going to get one the other day, but the Apple store only had 10W chargers on the shelf. The assoicate was not aware of the new adapter, but he was interested in finding out about it.
Doesn't matter anymore. Apple themselves said it'll charge previous devices faster!! They didn't say it was gonna be a 20%, they didn't even say a specific %, but they stated it should be faster.

http://9to5mac.com/2012/10/24/apple-confirms-that-12w-adapter-will-charge-ipads-quicker-than-older-10w-adapters/
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.