Does plugging phone in bypass battery?

Discussion in 'iPhone' started by Ferris23, Aug 2, 2008.

  1. Ferris23 macrumors 68020

    Sep 24, 2007
    I work in I.T so I am at a computer all day and leave my phone plugged in, when I am home I leave it plugged in as well. My theory is that if I'm not using battery, the battery will have a longer life. I do the same with my Macbook pro.

    I have done 2 discharges on both units to "calibrate" the battery. But my question, is my theory right, to prolong overall battery longevity not use it by using wall power instead?

    Am I a genius?
  2. Interstella5555 macrumors 603


    Jun 30, 2008
    #2 You're just continually charging the device, it's using the battery, but being replenished as it does. The battery will still degrade, and judging by my experience on my MBP plugged in all the time, not significantly different than regular use. Additionally, it's better for the battery if you get it under 20% at least once a month, with a full discharge every couple months.

    Nice try though :)
  3. fireshot91 macrumors 601


    Jul 31, 2008
    Northern VA
    yeah, its actually worse for your battery to keep it plugged in...not good man, itll make it worse n worse day by day, just get it under 30% once everyday, n then charge fully, and then repeat. but then once in a month. let it go down to 0%, and then charge(while it bieng off)
  4. macuserjames89j macrumors newbie

    Aug 3, 2008
    On the iPhone 3G your battery can drain down even while it is plugged in. My battery can drain completely even while it is plugged in while running certain high demand applications. But on the laptops there is a power management chip that takes part of the incoming power to actually run the machine and the other part to charge the battery. This is what allows you to run the machine without the battery attached if it is plugged into the wall. iPhones and iPod do not have this capability like it was stated earlier the phone only uses power from the battery, but the charger replenishes the diminishing charge unless the phone is draining the battery faster than it can be charged.

    Hope this helps.
  5. Ferris23 thread starter macrumors 68020

    Sep 24, 2007
    Thanks. So leave the MBP plugged in but not the phone
  6. marksman macrumors 603


    Jun 4, 2007
    I feel pretty comfortable in strenuously disagreeing with this.
  7. skubish macrumors 68030


    Feb 2, 2005
    Ann Arbor, Michigan
    This was true of older batteries but not modern batteries. Modern Li-ion batteries are rated in number of charge cycles. (i.e. 500) Its culmulative if you use 1% of the battery for 100days or 100% in 1 day its still 1 cycle.

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