Serenity12

Q: Can you charge iPhone with an iPad chargers?

Does using the iPad charger to charge an iPhone affect the life of the battery?

iPhone 5s, iOS 7.0.1

Posted on Jan 23, 2014 5:23 PM

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Q: Can you charge iPhone with an iPad chargers?

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  • by stedman1,

    stedman1 stedman1 Jan 23, 2014 5:28 PM in response to Serenity12
    Level 9 (73,667 points)
    Apple Watch
    Jan 23, 2014 5:28 PM in response to Serenity12

    No. It is perfectly fine to use the iPad charge for iPhones.

  • by Lawrence Finch,

    Lawrence Finch Lawrence Finch Jan 23, 2014 5:31 PM in response to Serenity12
    Level 8 (37,947 points)
    Mac OS X
    Jan 23, 2014 5:31 PM in response to Serenity12
  • by gaberdine mac,

    gaberdine mac gaberdine mac Mar 8, 2014 9:35 AM in response to Serenity12
    Level 1 (30 points)
    Mar 8, 2014 9:35 AM in response to Serenity12

    Yes it does. It shouldn't - but it does.

     

    People will tell you this is impossible - and they're wrong.

     

    People will twll you Apple say it's OK so it must be - and they're still wrong!

     

     

     

    iPad chargers are rated at 2A and iPhone chargers are rated at 1A because anything higher damages the battery. Of course the iPhone firmware should limit the charge current it draws to 1A or less (according to Apple's spec), regardless which adapter it is plugged into - but it does not!

     

    I have measured an iPhone 4s drawing 1.7A charge current at 5.2V from a plug adater (not Apple but a good make, designed for iPhone, rated at just 1.2A) - this is way too much.. When connected to a proper iPhone USB mains adapter rated at 1A, the same phone drew just 0.7A charge current - which is safe and correct.

     

    Apple seem to have written the firmware to allow faster charging of some iPhones if the source can provide more than 1A - this includes the iPad charger. I believe Apple have screwed that up since excessive charge current means an early death to Lithium batteries.

     

    In fact I firmly believe that this high charge current has reduced my battery life from a day and a bit to just half a day.

     

    Moral: Always use the wall charger that came with your phone. Don't mix iPhone and iPad chargers.

  • by Meg St._Clair,

    Meg St._Clair Meg St._Clair Mar 8, 2014 9:48 AM in response to gaberdine mac
    Level 9 (58,834 points)
    iPhone
    Mar 8, 2014 9:48 AM in response to gaberdine mac

    gaberdine mac wrote:

     

    Moral: Always use the wall charger that came with your phone. Don't mix iPhone and iPad chargers.

    Well, I'm going to take Apple's reccomendation and my own experiences over your single data point. I've been using iPad chargers with my iPhones since my iPhone 4S. Never had a problem of any kind. But then, I only use OEM chargers and cables.

  • by Chris CA,

    Chris CA Chris CA Mar 8, 2014 10:02 AM in response to gaberdine mac
    Level 9 (79,523 points)
    iPhone
    Mar 8, 2014 10:02 AM in response to gaberdine mac

    gaberdine mac wrote:

     

    I have measured an iPhone 4s drawing 1.7A charge current at 5.2V from a plug adater (not Apple but a good make, designed for iPhone, rated at just 1.2A) - this is way too much.. When connected to a proper iPhone USB mains adapter rated at 1A, the same phone drew just 0.7A charge current - which is safe and correct.

    So you used a non-Apple charger that feeds more power than it is rated for, it damages batteries and that is Apple's fault how?

  • by gaberdine mac,

    gaberdine mac gaberdine mac Mar 8, 2014 10:04 AM in response to Meg St._Clair
    Level 1 (30 points)
    Mar 8, 2014 10:04 AM in response to Meg St._Clair

    Whatever you do, Meg, I'm glad your experience is more positive than mine.

     

    I can only offer my experience, both empirical and experimental, that it appears this can be a problem.

     

    As for me being a single data point, the whole reason I looked into this was another thread (now locked) with various people claiming to have suffered loss of battery life from using iPad chargers with iPhones (it's not an unknown claim)... and a bunch of others telling them they were stupid and it was "impossible" for an iPhone to draw a higher charge current than 1A. Quite clearly it is not "Impossible".

     

    https://discussions.apple.com/message/19482712

     

    I don't claim my experience applies to all iPhones but I do stand by my claim that it applies to some. Whether I have a faulty iphone/firmware or there is a wider issue affecting a certain number of iPhones, I cannot say. But if the general question is "is it safe to use an iPad charger on an iPhone?" I will always advise the cautionary approach and say "no - not neccessarily".

  • by gaberdine mac,

    gaberdine mac gaberdine mac Mar 8, 2014 10:24 AM in response to Chris CA
    Level 1 (30 points)
    Mar 8, 2014 10:24 AM in response to Chris CA

    Chris CA wrote:

     

    So you used a non-Apple charger that feeds more power than it is rated for, it damages batteries and that is Apple's fault how?

    Oh Chris, you're missing the point.

     

    The charger is just a 5V power source. It doesn't dictate the charge current, except for its rated upper limit. Yeah it's an issue that the 1.2A charger is actuaslly providing 1.7A and I'll take that up with them - but Apple made the charging circuitry that controls what current it draws.

     

    The control of the charging current is done by the iPhone firmware. That's why it should be safe to use an iPad charger on an iPhone - just because it can provide 5v at 2A doesn't mean the iPhone is forced draw more than its rated charge-current (usually given as 1A). But in my tests it did. And not just on one phone.

     

    As for whether this really is the cause of my sudden nose-dive in battery life... well of course I cannot be certain. It would a cohort study of all users complaining of this issue. But it would be a mistake to assume that all iPhones perform the same or that because one phone suffered no harm, another won't. iPhones are not neccessarily identical maybe the affected ones have a different battery supplier - it wouldn't be the first time that Apple had experienced issues around components from differing source.

     

    So my advice remains, if you want to protect your battery only use an iPhone charger. I could be wrong - but nobody will be harmed by it.

  • by TJBUSMC1973,

    TJBUSMC1973 TJBUSMC1973 Mar 8, 2014 10:23 AM in response to gaberdine mac
    Level 5 (7,631 points)
    Mar 8, 2014 10:23 AM in response to gaberdine mac

    gaberdine mac wrote:

     

     

    Moral: Always use the wall charger that came with your phone. Don't mix iPhone and iPad chargers.

    No, the moral is to only use Apple-approved chargers.  Your example involved a non-Apple-approved charger, and therefore, your data is faulty & corrupted.

  • by stedman1,

    stedman1 stedman1 Mar 8, 2014 10:24 AM in response to gaberdine mac
    Level 9 (73,667 points)
    Apple Watch
    Mar 8, 2014 10:24 AM in response to gaberdine mac

    While you were measuring the output current, did you also monitor the output voltage to be a steady state 5vDC?

  • by gaberdine mac,

    gaberdine mac gaberdine mac Mar 8, 2014 10:31 AM in response to TJBUSMC1973
    Level 1 (30 points)
    Mar 8, 2014 10:31 AM in response to TJBUSMC1973

    Well, I know what you're saying but see my reply to Chris above.

    The charge current is controlled by the phone not the mains adapter.

     

    And I take it you don't recommend using any docking stations or iPhone alarm clocks or iPhone sound systems or iPhone DJ systems or anything else that charges an iPhone while you're using it? Cos there's quite a few of those in the Apple Store...

     

    http://www.apple.com/iphone/accessories/

  • by TJBUSMC1973,

    TJBUSMC1973 TJBUSMC1973 Mar 8, 2014 10:35 AM in response to gaberdine mac
    Level 5 (7,631 points)
    Mar 8, 2014 10:35 AM in response to gaberdine mac

    If it is approved by Apple for use with the device, then yes, I would recommend it.  By definition, if it is available for sale directly from Apple, and it charges the device, then it is an Apple-approved charger.

     

    Show me a charging accessory for sale from the Apple online store that is not approved by Apple.

  • by Chris CA,

    Chris CA Chris CA Mar 8, 2014 11:26 AM in response to gaberdine mac
    Level 9 (79,523 points)
    iPhone
    Mar 8, 2014 11:26 AM in response to gaberdine mac

    gaberdine mac wrote:

    The charger is just a 5V power source. It doesn't dictate the charge current, except for its rated upper limit. Yeah it's an issue that the 1.2A charger is actuaslly providing 1.7A and I'll take that up with them - but Apple made the charging circuitry that controls what current it draws.

    Then why doesn't the iPhone draw the full 1A available (or attempt to draw more) from the Apple charger?

    The charge current is controlled by the phone not the mains adapter.

    Then why doesn't it draw more from the Apple iPhone charger?

  • by gaberdine mac,

    gaberdine mac gaberdine mac Mar 8, 2014 11:53 AM in response to Chris CA
    Level 1 (30 points)
    Mar 8, 2014 11:53 AM in response to Chris CA


    Chris CA wrote:

     

    gaberdine mac wrote:

    Then why doesn't the iPhone draw the full 1A available (or attempt to draw more) from the Apple charger?

    The charge current is controlled by the phone not the mains adapter.

    Then why doesn't it draw more from the Apple iPhone charger?

     

    Sophisticated electronics. It draws what it "thinks" it needs to correctly shape the charge current over time. usually for an initial fast charge followed by a reduction to trickle charge.

     

    Both chargers present 5v nominal ± 0.2v

     

    The initial charge from both devices spikes at 1.7A then it drops down to 0.7A with the Apple iPhone charger but remains high with the more powerful charger. This is controlled by the iPhone. Testing carried out repeatedly on same phone with very similar charge levels

     

    If I'm right in my suspicion that this fast charge harms the battery life, it would be a firmware problem. I have no data on that, just emirical evidence and word of mouth experience. Much like all the people who say "it was never a problem for me".

  • by TJBUSMC1973,

    TJBUSMC1973 TJBUSMC1973 Mar 8, 2014 11:57 AM in response to gaberdine mac
    Level 5 (7,631 points)
    Mar 8, 2014 11:57 AM in response to gaberdine mac

    In other words, you're making uneducated guesses and using 'psuedo-science'.

     

    Apple says that the charger is compatible.  That's the final word.

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