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Charging with 12W Brick

Bbqthis

Bbqthis

macrumors 6502a
Original poster
Apr 12, 2015
935
1,844
Bay Area, CA
I know there was a thread about this a few weeks ago, but no consensus was drawn. Will the Watch charger faster with an iPad brick? Is there anymore info about this? Have any reviewers talked about this? If not we should all just tweet John Gruber or someone and see...
 
It won't charge any quicker than the circuitry will allow and given the size of the battery a 5w charger is going to offer the same charge time as the 10/12w chargers
 
The answer is virtually certain to be no. The battery is miniscule and charging at 2A would undoubtedly shorten the battery life.
 
rkuo said:
The answer is virtually certain to be no. The battery is miniscule and charging at 2A would undoubtedly shorten the battery life.
Click to expand...

2A is the maximum a device can draw not the current that will be supplied. I am 99% sure that a high amp charger will not affect the battery life.
 
DavidWildJnr said:
2A is the maximum a device can draw not the current that will be supplied. I am 99% sure that a high amp charger will not affect the battery life.
Click to expand...
The question was would it charge faster, not would it affect the battery life.
 
DavidWildJnr said:
2A is the maximum a device can draw not the current that will be supplied. I am 99% sure that a high amp charger will not affect the battery life.
Click to expand...

Incorrect. Given how small it is, that high of current can reduce its life. Source: my 7.5 years experience working R&D in the battery industry. Apple puts in safeguards to prevent excess charging, so one can use a 12W charger without fear.

Also, someone posted, I recall they sourced one of the tech reviews, that it will not charge faster.
 
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madsci954 said:
Incorrect. Given how small it is, that high of current can reduce its life.
Click to expand...

Both the 5W and the 12W charger provide 5V, the charging circuitry inside the watch (or MagSafe puck) alone is what determines the current drawn. The chargers only differ in the amount of current they are able to deliver.

Source: my 7.5 years experience working R&D in the battery industry.
Click to expand...

Oh my.
 
dotnet said:
Both the 5W and the 12W charger provide 5V, the charging circuitry inside the watch (or MagSafe puck) alone is what determines the current drawn. The chargers only differ in the amount of current they are able to deliver.
Click to expand...

That's essentially rephrasing what he said but with details I think most people could interpret. :confused:
 
dotnet said:
Both the 5W and the 12W charger provide 5V, the charging circuitry inside the watch (or MagSafe puck) alone is what determines the current drawn. The chargers only differ in the amount of current they are able to deliver.



Oh my.
Click to expand...

And what I believe he's saying, that if the watch charged at 2a (i.e. if it *chose* to draw 2a) it would shorten the battery's life.

There is a difference between connecting to a 2a charger (and charging at 1a), and charging at 2a (which is what he said). He did not say that connecting it to a 2a charger may damage it. He said that charging at 2a may damage it.
 
Brian Y said:
He did not say that connecting it to a 2a charger may damage it. He said that charging at 2a may damage it.
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Sure, but we don't get to choose how much current goes into the battery. The charge logic in the device (any device that has a built-in Li-ion or similar battery) controls and monitors the charge process, this is the only way the batteries can be charged safely, efficiently and with predictable results.

Our job is simply to provide a source of electrical energy in the correct voltage range for the charge logic to operate, and with sufficient ability to deliver the current required for charging the battery.

If the power adapter we use is beefier than required then either of two things can happen:
  1. the charging circuitry can make use of the extra power and charge the battery faster (but still withing safe specs)
  2. the charging logic will draw the same current as with the standard charger, and we've wasted our money

If the power adapter is underspec'ed (e.g. a computer USB port) then either of these two things can happen:
  1. the power adapter can get damaged (unlikely, because they are usually designed to protect themselves from excess current draw)
  2. the charge logic recognises the reduced ability of the power adapter (either through communication with it or by monitoring the supplied voltage, which will drop), in this case charging of the battery will simply take longer.

There is no danger of damaging or harming the battery in devices like the watch or the iPhone, as long as one provides the correct voltage (5V in this case).
 
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dotnet said:
There is no danger of damaging or harming the battery in devices like the watch or the iPhone, as long as one provides the correct voltage (5V in this case).
Click to expand...

That's a long explanation just to be right and have the last word.

That is exactly what was implied.
 
dotnet said:
Sure, but we don't get to choose how much current goes into the battery. The charge logic in the device (any device that has a built-in Li-ion or similar battery) controls and monitors the charge process, this is the only way the batteries can be charged safely, efficiently and with predictable results.

Our job is simply to provide a source of electrical energy in the correct voltage range for the charge logic to operate, and with sufficient ability to deliver the current required for charging the battery.

If the power adapter we use is beefier than required then either of two things can happen:
  1. the charging circuitry can make use of the extra power and charge the battery faster (but still withing safe specs)
  2. the charging logic will draw the same current as with the standard charger, and we've wasted our money

If the power adapter is underspec'ed (e.g. a computer USB port) then either of these two things can happen:
  1. the power adapter can get damaged (unlikely, because they are usually designed to protect themselves from excess current draw)
  2. the charge logic recognises the reduced ability of the power adapter (either through communication with it or by monitoring the supplied voltage, which will drop), in this case charging of the battery will simply take longer.

There is no danger of damaging or harming the battery in devices like the watch or the iPhone, as long as one provides the correct voltage (5V in this case).
Click to expand...

That's exactly what was said?

The argument isn't whether plugging something into a higher powered adapter will damage the device. It's whether if Apple had allowed the watch to pull 2A (and therefore charge at 2A) the lifespan of the battery, given how small it is, would be reduced.
 
OP here. Anyway, I asked John Gruber and he said he hadn't tried it but he's pretty sure it doesn't charge faster with the 12 W brick.
 
Well Apple is selling both the chargers in their accessories section for Apple watch. I'm pretty sure it won't impact your battery life and give you a quicker charge option like in case of iPhones
 

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saksvig said:
Well Apple is selling both the chargers in their accessories section for Apple watch. I'm pretty sure it won't impact your battery life and give you a quicker charge option like in case of iPhones
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Pretty sure you can charge with either brick but the charge time will be the same.
 
Just a suggestion but see what the current draw would be on a MBP (like what an iphone 6/6+ does). Does it draw out the 500 + 1600 or only 500 or only 500 + 500 under the system info.
 
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