Battery health drop

Discussion in 'MacBook Air' started by massi88, Sep 9, 2013.

  1. massi88 macrumors newbie

    Sep 9, 2013
    Hi everybody,

    I've bought a new macbook air 13'' (i5, 8Go, 256 Go) three weeks ago, I had a battery capacity of 7450mAh, and yesterday it dopped to 7100mAh.. is this normal? nearly a 1% health drop after three weeks and 8 cycles? :eek:

    I took care of the battery though (always on sector, 50% use of battery at least once a week) :confused:

    Thanks for the answers.
  2. GGJstudios macrumors Westmere


    May 16, 2008
    It is perfectly normal if your battery health (maximum capacity) is more or less than 100%, even when brand new, or if it fluctuates up or down over time. The gradual decline is not in a straight line downward, and it may decline more rapidly at some times and slower at others. For further details, read the CHECKING STATUS AND HEALTH section of the following link.
    The link below should answer most, if not all, of your battery/charging questions. If you haven't already done so, I highly recommend you take the time to read it.
  3. massi88 thread starter macrumors newbie

    Sep 9, 2013
    Ok thanks! Just out of curiosity, how come a battery capacity can drop over 1% in one night? What's the physics behind these up/down evolutions?
  4. robvas macrumors 68030

    Mar 29, 2009
    Don't watch the specs everyday you will drive yourself nuts.
  5. GGJstudios macrumors Westmere


    May 16, 2008
    The health is only an estimate. Also, a change of 1% in the displayed health could be a change of a fraction of a percent, such as going from 97.5% to 97.4% or going from 98.0% to 97.95%, depending on how rounding is done. Really, a change up or down of even several percentage points is nothing to worry about. I encourage you to relax and enjoy your Mac and not obsess about the battery.

    Run on battery whenever you need to and plug it in whenever you can. You can plug or unplug any time you need to, regardless of the charged percentage, and you never need to completely drain your battery. Just make sure you don't run on AC power exclusively, as your battery needs to be used regularly to stay healthy.
  6. mizaco macrumors member

    Sep 4, 2013
    How old is that battery? When was the date of purchase?
  7. GGJstudios macrumors Westmere


    May 16, 2008
    From the first post:
  8. massi88 thread starter macrumors newbie

    Sep 9, 2013
    Ok I guess I should just enjoy it as you said, but if the battery continuously drops to 90% within one or two months I'll have it checked at the apple store because that wouldn't be normal despite what you explained..I expect it to be above 95% as long as I'm under 150/200 cycles, which according to my usage would be something like a year.
  9. GGJstudios macrumors Westmere


    May 16, 2008
    As I stated previously, it is normal for the decline to be more rapid at some times than others. Apple will usually not consider a battery to be defective until it drops below 80%. Many have reported a drop to around 90% in a couple months, then have it remain near that level for a year or more. It is all quite normal. There is no indication of a defective battery, simply because it drops below 95% before 200 cycles. The only threshold that counts is dropping below 80% before 1000 cycles, which is Apple's criteria for a defective battery.
  10. massi88 thread starter macrumors newbie

    Sep 9, 2013
  11. filmbuff macrumors 6502a


    Jan 5, 2011
    My battery fell to 90% within a few months of purchase but I knew that was normal so I didn't worry. Now my laptop is 13 months old with 178 cycles and it is at 85% and slowly falling. Should I be getting concerned? It's not falling quickly but at this rate I don't see how it will get to 1000 charge cycles.
  12. bp1000 macrumors 65816

    Jul 7, 2011
    My late 2011 is now fluctuating between 76% and 80%. It is also saying service battery on occasion too.

    Lasts between 3 and 4 hours.

    I've tried everything, full drains, partial drains, random charging, charging to 100% from 0, keeping it between 50% and 70%. Nothing improves matters, it just keeps falling.

    Just 2 months ago I was around 83-85% health, 6 months ago 87% health.

    Health is falling off the cliff and I'm doing everything i should be for a healthy battery.
  13. lobo1978 macrumors 6502


    Sep 22, 2011
    your battery 'dropped' to nominal capacity

    Just to remind nominal capacity for 2013 Macbook Air 13" is 7150. For a few first cycles it is higher than nominal...

    Just use it and don't keep it on charger for a long time.

    BTW mine dropped from 7500 to 7212 (I am on 8th cycle now)
  14. GGJstudios macrumors Westmere


    May 16, 2008
    No, you shouldn't worry. As stated earlier, it will decline faster some times than others. If it drops below 80% before 1000 cycles, take it to Apple.
    The "service battery" indication automatically appears when the health drops below 80%. It doesn't necessarily indicate that there is another problem with your battery. If it still holds sufficient charge to meet your needs, you can continue using the battery, even if the health is below 80%.
    There is nothing you can do to prevent a battery's health from declining. Batteries are consumable items and will eventually die. Just relax and enjoy your Mac and replace the battery when it no longer holds sufficient charge to meet your needs.

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