Too much draw from battery.. early-2011

Discussion in 'MacBook Pro' started by thermodynamic, Sep 15, 2012.

  1. thermodynamic Suspended


    May 3, 2009
    I've not used the battery in a while so I thought I'd let the MBP run on battery...


    Why would the Current capacity be greater than the designed capacity?

    Is the system (even when idle) using more energy than what can be provided?

    Or is the battery a slightly higher quality?

    With the VM closed down, current capacity goes down to 8751 with amperage going down to 1272 (I have an XP VM used to test web sites during development... that's all it is used for and it runs 512MB with 1 core designated for it... very minimal...)

    With AC plugged in, amperage goes down to 1088 (idle) and skyrockets when the VM is enabled... (or any CPU-intensive task, of course...)

    The number is fairly small, but if the demanded mAh is higher than what the battery is capable of, surely that will wear out the battery more quickly? :(

    Assuming iStat 3 is accurate in its presentation, of course...
  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. For further details, read the CHECKING STATUS AND HEALTH section of the following link.

    Also, It's normal for your MBP to draw power from both AC and battery during periods of extreme demand, such as gaming or other multimedia operations. This can cause your battery to stop charging or even drain, even though it's plugged in. Read the AC POWER 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. dusk007, Sep 15, 2012
    Last edited: Sep 15, 2012

    dusk007 macrumors 68040


    Dec 5, 2009
    I don't understand what you problem is. I think you must have some stuff confused.

    Just enable in iStat the more naturally understandable Watts. iStat actually can calculate that value for you and it is much more meaningful.
    In your screen you are drawing some 43W from your 99Wh battery. Idiots Math will tell you that this means after one hour of continued 43W you'd be at half capacity. It is really simple. I think something about mA is confusing you. No idea what I cannot make sense of it.
  4. afinch1992 macrumors 6502


    Sep 13, 2012
    Dallas, Tx
  5. thermodynamic thread starter Suspended


    May 3, 2009
    Thanks! I do tend to get things backwards at times...

    If I wasn't, then I wouldn't be asking... Per the full message you'd written (I truncated it just to get to the point), I'll definitely look deeper into iStat's settings... thanks!

    Thanks. :)
  6. killerrobot macrumors 68020


    Jun 7, 2007
    Looks normal. FYI I've burnt through a full battery in under an hour while gaming. The AMD card loves sucking that battery up.

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