does charging through the usb port affect macbook battery?

Discussion in 'MacBook Air' started by jetlagged, Mar 28, 2016.

  1. jetlagged macrumors 6502

    Sep 6, 2012
    i own a macbook air 2012 13", (bought it in november 2012)my battery monitor shows my battery is at 4611 mah max capacity now, out of 6700 when i first bought it. it says to replace the battery. but i'll do it in the near future, not right now.

    i like to charge my ipad or iphone, or external mini battery charger, or camera (point and shoot or gopro) through the usb. when i do charge it, i make sure my macbook air is connected to the wall socket for power. i'm wondering, does charging electronics through the usb port affect battery life in the long run? or does it have no effect?
  2. Opes macrumors newbie

    Nov 16, 2008
    No, it will not affect your battery as it is running on power from the Magsafe adapter.
  3. gnasher729 macrumors P6


    Nov 25, 2005
    What affects your battery life is when the battery inside your MacBook discharges. What it does with that energy doesn't matter. If your MacBook was unplugged and you used it to charge an iPad or iPhone, it would discharge and cost battery life. If your MacBook is plugged in it should remain 100% charged, so there is no negative effect on your battery.

    (As always, use common sense. You have about 1,000 battery charges. If you need your iPad and the only power source is the MacBook without a charger, charge your iPad. )
  4. rigormortis, Mar 28, 2016
    Last edited: Mar 28, 2016

    rigormortis macrumors 68000


    Jun 11, 2009
    ever since 2007, when the iPhone came out, and 2010 when the ipad came out, macs have been designed specifically to charge their iOS devices at a higher then normal usb current. your average macbook/mac mini/imac/mac pro puts out the same power output as an ipad charger. this is a feature that cannot be turned off by the user. if apple felt that it was damaging iOS devices or the computer, they would of done something about it by now.

    i don't own any usb c devices or ipad pros, so i have no idea what their current tops out at.

    apple has limited your ability to crank the volume of your macbook pro, so the speakers will last. you think they would be the first ones to stop macs from charging iPhone 6 phones at 5v @ 2100 ma

    the only thing about iPhones you need to know, is that if you want to charge your 6s or 6s plus at 2100 ma using your mac you are required to update to el capitan, if you do not run el capitan , then it tops out at 1000 ma. however the older 6 and 6+ still continue to charge at 2100 ma on mavericks

    the moral of this post is. do not waste money on any Kickstarter cables that promise to deliver double the power to your iPhone if you flick the "charge/sync" switch. those cables are only required for windows machines.

    this is my favorite subject to troll about. i read blogs all the time saying how you can't measure how much current some iOS device takes when you connect the iPad charger. and you have to use a stopwatch. thats a bunch of hogwash. if the magnetic charging cable from your apple watch does not ask for more then 5 V @ 1000 ma from your mac book pro, how is it gong to ask for 2100 ma from the ipad charger?

    the client must ask the host controller how much power it wants. the host can't just automatically dump power to the client. it is not allowed to do this

    this subject is a real pet peeve of mine. people go around and say their phones are better because they have quick charge. yeah , apple invented the quick charge. before the ipad came out, there was no real usb port available that was capable of putting out the voltage the ipad wanted

    maybe if it wasn't for steve jobs, we would be all using point of sale usb
  5. Gav2k macrumors G3


    Jul 24, 2009
    Ok it won't damage your battery BUT given the MagSafe charger in some cases cannot maintain the MacBooks consumption and battery discharge occurs on occasion your iPad/iPhone will be depleting your battery.

    Will this have an effect? Yes. You will go through the battery life quicker resulting in you charging the battery.
  6. rigormortis macrumors 68000


    Jun 11, 2009
    yeah. i think the only situation i can think of where the charger can't maintain the computer is if you bought the 60W adapter for a computer that requires a 85W adapter. i read an apple support article that specifically said that there is no benefit from using the 85W on a 60W , so when my cable got frayed i just bought a new 60W

    i got this weird battery error. PPT 004. i tried resetting pram and smc , its stuck there. i took it to the genius, and they ran their probes on it , and both their test and os x say the battery is fine. i think my macbook flagged the battery as bad permanently , even though its ok

    i think PPT 004 means it runs down quick? i dunno. it past their test
  7. Gav2k macrumors G3


    Jul 24, 2009
    Ppt004 is the battery service warning

    As got the 85w vs 60w if the Macbook came with an 85w you should use the 85w. Using a 60w won't cause any damage but charging speeds will be effected.

    Most MacBooks esp the dgpu models can exceed the ac adapters output and use the battery for suplimentry power. This can be seen more so when the battery is removed or faulty.
  8. rigormortis macrumors 68000


    Jun 11, 2009

    does anyone actually know what PPT004 actually means? and how to clear it? they tested the battery on their system and its fine. I'm worried that this error that appears to be false , will affect whatever selling price in the future

    my theory is apple's test only checks the counters ( max capacity when new charge recycles ) and this ppt 004 means high drainage? or maybe i went to 5% too many times? its like my battery has been permanently flagged by some bios test and there is no way to clear it

    i thought the official apple battery test would check the battery, say its fine, and then tell the apple hardware test that its okay, but it doesn't. i figured apple would clear it like a check engine light, but they can't
  9. Gav2k macrumors G3


    Jul 24, 2009
    The battery requires service. The battery is not functioning normally, though you may not notice a change in its behavior or the amount of charge it holds. You can continue to use your battery before it’s checked without harming your computer.

    Above is exactly what it means. What they should have done is checked the battery then cleared the message for you

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