“iPhone 6 and iPhone 6 can also play the quick-charging game,” Elise Ackerman reports for Forbes. “Just plug them into the 2.1A/12W charger from an iPad or the high-power USB port of a newer model Mac. This raises the question, why doesn’t Apple advertise this feature? And, more importantly will it hurt your phone if you try this?”
“It is possible to deduce from the web page Apple created ‘Charge the battery in your iPad,’ that Apple is aware of this capability and endorses it,” Ackerman reports. “The Apple store lists every iPhone from the original ‘iPhone” to the iPhone 6 plus as being compatible with the charger.'”
“Isidor Buchmann, founder and CEO of Cadex Electronics and author of ‘Batteries in a Portable World,’ explains a key measurement that determines how much charge a phone can safely receive is the C-rate, or the rate at which a battery charges or discharges,” Ackerman reports. “To determine a C-rate, simply take the ratio between the charging rate and the capacity of the battery as measured in mAh or milliampere-hours. For an iPhone 6 that is being charged with the iPad charger, the C-rate is 2100mA/1810mAh or 1.16C. For an iPhone 6 Plus, the C-rate is 2100mA/2915mAh or .72C.”
“Most portable batteries are rated at 1C,” Ackerman reports. “This puts the C-rate that we calculated for the iPhone 6 and 6 Plus in the safety zone. ‘A battery manufacturer would recommend a rate below 1C,’ Buchmann said. But a rate that is just barely above 1C is nothing to be concerned about.”
Much more in the full article – recommended – here.
I don’t know about the iPhone 6 or 6 plus, but I remember reading somewhere that all previous iPhones charge at 1A whether you use an iPhone charger or an iPad charger. The iPhone circuitry determines how much amperage is going into the battery. In other words, you can’t push more amps in – than the system is designed to draw. Kinda like your wife using her curling iron. The iron draws 5 amps, but the outlet supplies 15 amps. Even though more amps are available, the iron will not draw more amps than it needs (unless it develops a short).
I know my 4S charges at the same speed with either charger.
Not exactly, 6’6″.
Where does Apple inform the user of any protective circuitry that can possibly prevent too much current from damaging your iPhone battery?
The big problem is that even old electrical engineers muddy the waters by using resistive circuit analogies rather than addressing the real question. The issue is whether fast charging damages a battery. The answer, for almost all battery chemistries, is YES. What rate of charge can the iPhone or iPad handle? Apple offers no guidelines. But it is indisputably true that an iPhone that always uses the iPhone charger will have a more durable battery lifetime than an identical iPhone that was “fast charged” using a higher power iPad charger. I suppose at some level it’s user preference, but given how bad iPhone batteries last now, one would think that trickle charging is the better policy.
Note the following power differences:
most USB chargers: ~ 2.5 watts
iPhone: ~ 5 watts
iPad: ~ 10 watts
One would hope that “Made for iPhone” accessories are all validated by Apple to not cause damage, but the end consumer isn’t informed by Apple about this stuff. The tinkerer could easily build a faster charger which, if he overdid it, could kill the battery rather quickly.
Apple documentation could be improved.
Forgive me, fanboys, for criticizing Apple’s lack of documentation on this area. Apple seems to think that user forums will clear up any questions so they don’t bother. Problem is, most forums are filled with people who have no electrical knowledge whatsoever, and even if they can do basic circuit analysis, they haven’t a clue what battery they’re dealing with.
It was a good post until you polluted it with the inflammatory “fanboys.” You just undid any potentially useful analysis. Now I don’t trust it because I think you’re just trying to discredit Apple users like me. How’s this: Go away Android troll.