How long will a MB battery hold its charge for?

Discussion in 'Mac Basics and Help' started by MST, Aug 25, 2008.

  1. MST macrumors 6502

    MST

    Joined:
    Dec 3, 2007
    Location:
    Surrey, UK
    #1
    I have been thinking about getting myself an extra battery for my MB so that I can use it for longer when I don't have access to a power outlet, but I've been wondering how long an unconnected battery would hold it's charge for, can anyone shed any light?
     
  2. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
  3. Scepticalscribe Contributor

    Scepticalscribe

    Joined:
    Jul 29, 2008
    Location:
    The Far Horizon
    #3
    My MBP averages much the same, 4-5 hours on a charge. Cheers
     
  4. MST thread starter macrumors 6502

    MST

    Joined:
    Dec 3, 2007
    Location:
    Surrey, UK
    #4
    Thanks for the responses, but what I really want to know is if I fully charge a spare MB battery how long will it hold that charge for before I connect it to the MB?; I got the impression that your response was stating your average battery life, apologies if this was not the case.
     
  5. clevin macrumors G3

    clevin

    Joined:
    Aug 6, 2006
    #5
    depends, screen brightness, wi-fi are all big drain, you can get anywhere from 3-5 hours with normal usage.

    battery also degrades through time. especially at elevated temperature.

    ooo, it will hold for years.

    But if you were to store a battery for a lengthy period of time, you might want to keep it at 40% charge, and in a cooler environment.
     
  6. misterredman macrumors 6502a

    misterredman

    Joined:
    Oct 3, 2007
    #6
    Taken from here:

    http://www.apple.com/batteries/notebooks.html

    Long Term Storage

    If you don’t plan on using your notebook for more than six months, Apple recommends that you remove and store the battery with a 50% charge. If you store a battery when it’s fully discharged, it could fall into a deep discharge state, which renders it incapable of holding any charge. Conversely, if you store it fully charged for an extended period of time, the battery may experience some loss of battery capacity, meaning it will have a shorter life. Be sure to store the ejected battery at the proper temperature. (See “Notebook Temperate Zone.”)
     
  7. iToaster macrumors 68000

    iToaster

    Joined:
    May 3, 2007
    Location:
    In front of my MacBook Pro
    #7
    It's generally not recommended to leave a battery unused for long periods of time without use on a full charge, but the charge won't go down to zero easily in a few weeks. I have an unused PowerBook battery sitting around (as it needed a new battery) and every once and a while I'll pull it out to check on it. I pulled it out at 100% and haven't used it yet since the beginning of April. As of now the LEDs on the bottom indicate an almost full charge (4/5). I'd say it wouldn't be wise to leave one battery unused for a long as it would have an effect on its overall health, but one cannot deny the advantages of a second battery.
     
  8. MST thread starter macrumors 6502

    MST

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    Dec 3, 2007
    Location:
    Surrey, UK
  9. DoFoT9 macrumors P6

    DoFoT9

    Joined:
    Jun 11, 2007
    Location:
    Singapore
    #9
    a second battery is an excellent idea.

    i have two and use them on a rotational basis because im at uni all day long. i have my newer battery as my "good" battery which i completely use everytime to keep it healthy. my other battery i use as a "whatever" battery and i recharge it whenever because it doesnt need to be healthy.

    the battery will probably hold its charge for years.. however its said by apple that if your gonna store it for more than a few months reduce the batteries charge to 50% so that it doesnt damage it.
     

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