Macbook slow charge, fast drain and says full at 90% (late 08 unibody)

Discussion in 'Mac Basics and Help' started by g35, Aug 22, 2013.

  1. g35, Aug 22, 2013
    Last edited: Aug 22, 2013

    g35 macrumors 6502a

    Joined:
    Dec 13, 2007
    #1
    I just bought a used Macbook late 2008 unibody version. Everything seems good except some quirks with the battery. It was sold to me while running OS X 10.9 (13A538g) which I understand is a beta. Could that be the cause of these problems/should I try to revert to an older OS?

    It charges slowly (like 3-4 hours) despite only having about 2-2.5 hours battery life. I thought if it's quick to drain, it's also quick to charge? And while charging, the estimated time left to recharge goes up and up for a while, then eventually descends but very slowly, like takes an hour to go from 0:55 to 0:30 - even though I'm not doing anything very intensive on the computer.

    Another thing is the battery indicator near the clock will say fully charged, but if I unplug and replug the charger it will show some amount in the 90s. Then very soon it will again say fully charged, and the whole process can be repeated if desired.

    It also drains a lot overnight while sleeping, like 30%.

    So far I have done an SMC reset (or I think I did - I don't know if it was successful). I have also made sure there are no runaway CPU processes.

    Now I'm planning to charge for 2 hours, run down the battery, then let it rest for 5 like Apple says to calibrate the battery. But if that doesn't work does anyone have any suggestions on how to fix this, short of buying a new battery? Coconut battery says 83% health after 1238 cycles and option-clicking the battery icon says condition is normal.
     
  2. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #2
    The estimated time to recharge actually very up-and-down, based on the workload on your system at any given point in time. If you have resource-intensive apps running, it will naturally take longer to charge than if you had little or nothing running. The time required to drain the battery has no impact whatsoever on the time required to charge it.

    It's normal that your battery may stop charging between 93-99%. For details, read the CHARGING section of the following link. It is draining 30% overnight, it is possible that it is not remaining in sleep mode during the entire time. It should drain approximately 1% for every hour of sleep.

    Instructions for resetting the SMC appear in the link at the bottom of the CHARGING 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. g35 thread starter macrumors 6502a

    Joined:
    Dec 13, 2007
    #3
    Thanks for the link. Some things that came up:

    -according to the link and all google results, I think they are referring to the battery saying it's fully charged and showing 95% (or similar) in the percent at the same time. Mine says 100% and fully charged even though it seems able to take some more capacity. Is this the same issue for both me and what's linked in the article/Google? Because mine never says fully charged while showing a number in the 90s. But the Apple article specifically refers to showing full charge but percent between 95-99.

    -and do you know why it could be taking so long to charge, or is 3-4 hours a typical amount? This is on different plugs in different buildings. As far as I can tell the charger is genuine but who knows.

    I appreciate you taking the time to reply to my thread :)
     
  4. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #4
    Your battery will not charge beyond 100%. Once the battery is fully charged, it stops charging and runs on AC power, if left plugged in. Only in very rare circumstances will your MacBook draw power from both AC and your battery, such as during extreme gaming.

    If it is taking longer to recharge, it may be because you have processes that are placing higher demands on your system. To determine if this is true, follow every step of the following instructions precisely. Do not skip any steps.
    1. Launch Activity Monitor
    2. Change "My Processes" at the top to "All Processes"
    3. Click on the "% CPU" column heading once or twice, so the arrow points downward (highest values on top). (If that column isn't visible, right-click on the column headings and check it, NOT "CPU Time")
    4. Click on the System Memory tab at the bottom.
    5. Take a screen shot of the entire Activity Monitor window, then scroll down to see the rest of the list, take another screen shot
    6. Post your screenshots.

    The other possible culprits for slow charging may be a bad connection with your power adapter, a faulty power adapter, a defective battery, a loose battery connector inside your MacBook, or even a problem with your logic board. If you have properly reset the SMC using the instructions I linked, and determined that there are no processes placing high demands on your system, you may consider taking it to Apple to have them run some hardware diagnostic tests.
     
  5. jav6454 macrumors P6

    jav6454

    Joined:
    Nov 14, 2007
    Location:
    1 Geostationary Tower Plaza
    #5
    There is your problem. You bought it used which means the battery is the original one. By now, that battery has very likely lost a 75% battery charge capacity. How do I know? I own one, and the exact same thing happened to me 4 months ago.

    Want to know the state of your battery? Download and install CocunutBattery. It's a free app that will tell you the state of your battery and how much it an hold. It will also list the cycle count (how many times it has charged and discharged completely) of the battery.
     
  6. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #6
    From the OP:
    Although, it's very unlikely that the health is accurate.
     
  7. phoenixsan macrumors 65816

    phoenixsan

    Joined:
    Oct 19, 2012
    #7
    Maybe.....

    you have to consider a simpler approach: If the battery is the original one, maybe this is worn out. I know you checked about the cycles and health, but sometimes software is not so acurate.

    Maybe you can check with a local Mac shop with a newer battery what fits your computer and sees how that goes. Can be worth, IMHO.....



    :):apple:
     
  8. jav6454 macrumors P6

    jav6454

    Joined:
    Nov 14, 2007
    Location:
    1 Geostationary Tower Plaza
    #8
    I read that and ignored it immediately. No battery is "normal" after 1238 cycles.
     
  9. g35 thread starter macrumors 6502a

    Joined:
    Dec 13, 2007
    #9
    Thanks for the advice everyone but I decided to sell it and that it wasn't worth the risk of having something stop working + poor battery life.
     

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