Why does Apple still sell the 5v iPhone charger (vs 12v)?

Discussion in 'Mac Accessories' started by DaveTheRave, Mar 12, 2014.

  1. DaveTheRave macrumors 6502a

    May 22, 2003
    They are the same price but the 12v charger can charge phones and iPads. 5v can only charge a phone, unless you want to wait much much longer for it to charge the iPad. Why not sell a universal charger and simplify?
  2. FreakinEurekan macrumors 68040


    Sep 8, 2011
    Eureka Springs, Arkansas
  3. paulrbeers macrumors 68040

    Dec 17, 2009
    Ummm... All iPads and iPhones are 5V. You mean 5W vs 12W which is voltage times amperage. If all you have is iPhones and iPods, the smaller charger is nice. It isn't like your phone will charge any faster (relatively) on the larger charger, and the small 5w cube is much more portable.
  4. southerndoc macrumors 65816


    May 15, 2006
    Maybe the laws of physics don't exist at my house, or maybe I'm just completely wrong, but the 12W charger does charge my iPhone a lot quicker than the 5W.
  5. g4cube macrumors 6502a

    Apr 22, 2003
    Depends on the iPhone.

    yes there is circuitry inside the newer iPhones that take advantage of the additional power from the 12W charger.

    Older iPhones don't benefit. So if you have 4s, 5, or 5s a charger with more current available like the 12W charger will charge faster.
  6. Richdmoore, Mar 12, 2014
    Last edited: Mar 12, 2014

    Richdmoore macrumors 68000


    Jul 24, 2007
    Troutdale, OR
    Is there some benchmark, test, or other documentation that the new iPhones charge faster? I believe it, but I have never been able to find any proof from apple or an objective benchmark.

    The best I found online was a YouTube video with a kill-a-watt meter showing the older iphone doesn't draw any more from the 12w than the 5w (although the iPad mini did) but it is somewhat dated now, as this was before the lightning connector I think.
  7. paulrbeers macrumors 68040

    Dec 17, 2009
    You'll need to point me to the data sheets to prove this.....

    Edit: The only evidence of faster charging with an iPad charger over an iPhone charger has been that the iPhone chargers aren't as good at retaining full draw over a long period of time (they tend to fluctuate). Using a larger charger means that you aren't maxing the 12w so you might get a more steady charge.

    This is purely anecdotal and I haven't taken time to validate just other internet "rumors" I have read.
  8. g4cube macrumors 6502a

    Apr 22, 2003
    Sorry. No data sheets. Just personal experience with 4s and 5s.
  9. paulrbeers macrumors 68040

    Dec 17, 2009
    Then where did you get the line....
    yes there is circuitry inside the newer iPhones that take advantage of the additional power from the 12W charger.

    That can't be "personal experience" to state there is circuitry.... Or is that purely speculative (which you probably should state if you make such a statement).
  10. g4cube macrumors 6502a

    Apr 22, 2003
    TL;DR: "my informed opinion"

    Longer version:

    By measuring the current consumed, figuring out the circuitry, and applying my engineering knowledge. There is a USB charging spec available in the industry that describes how to apply up to 2.1A @5v to charge via USB.

    ASMedia is one company whose USB controllers are able to do this.

    Apple devices are known to place a certain resistor value across the USB signaling lines that instruct some adapters to provide different power levels. OS X and iOS also can detect when a non-Apple charging accessory is used that does not contain the proper licensed authentication inside.

    On certain Apple computers, Apple knows when specific Apple devices are connected to compatible USB ports, adjusting the available power. This started way back on the G4CUBE computer (no relation to me :D ). The bundled USB speakers had incredible volume because the G4CUBE could provide additional current when those particular speakers were attached.

    Similarly, the Apple Superdrive requires more power than a standard USB port can provide, so Apple's Macbooks are able to deliver additional power over the USB ports when the Superdrive is connected.

    There are reports of various USB chargers where people have disassembled them to figure out the specifications and power limitations, in addition to power quality. Google is your friend.

    But you are correct this is my opinion, and Apple has not stated this in any public documents.

    On a related note, there have been other published reports and technotes by Apple explaining that a standard USB port on some computers will not charge an iPad or an iPhone, as those ports only can supply 2.5w as power available is 5v @500ma.

    And the original aluminum 15" Powerbook complained if a USB device that consumed more than 500ma was connected, and hut the port down.

    So...if you have a voltmeter, a dynamic load, something to measure current, and some design skills, you too can take a peek behind the curtain and discover what capabilities Apple devices have.

    Just a word of caution though, you can't always count on using hardware capabilities that are not actually guaranteed by Apple for non-Apple use. Especially on the software side, as there are many internal system APIs that Apple has not published but uses with their own applications. Developers get bit when they use them without authorization.
  11. bniu macrumors 6502a

    Mar 21, 2010
    I hear you on this, I don't bother with 5W chargers and only buy the 12W versions and have them plugged in all over the house. This way, all I have to do is find a lightning cable and plug it in, no need to think if it's a high wattage one or not. Same with my MacBook chargers, all 85W, works on any macbook I have.
  12. DaveTheRave thread starter macrumors 6502a

    May 22, 2003
    Lol it's annoying to have to explain to family that yes the iphone charger can also charge an ipad but very very slowly. So both chargers work on both but only one works really well on both…

Share This Page