Macbook Pro Battery

Posted:
in Current Mac Hardware edited January 2014
Hi all.



New to the forums, and only had a mac for three months, so I hope i'm welcome!



Erm, for the last few days i've been worrying about my battery, I know it's silly and everything, but it's supposed to have 7 hours. It will go for a good 5 hours, sometimes more than that. But the percentage rate seems to be going down quite quickly. e.g half an hour ago it was at 73%, now at 62%.



The battery time also changes quickly, from 6 hours 42, to 2hrs 32, back up to 4hours, etc.



I have checked the condition on Coconut Battery and it's at 100%.

Comments

  • Reply 1 of 2
    mr. hmr. h Posts: 4,698member
    The battery life you get will depend on what you are doing with the machine. The battery life is "up to" 7 hours, when browsing the web (presumably with very few, if any, animations, video or flash content) with the display brightness set to 50%.



    If you increase the CPU or GPU usage, battery life will go down, possibly dramatically. The battery life indicator tends to give a battery life according to what you're doing right now (i.e., if it says 2 hours, the battery should last 2 hours with the current CPU and GPU usage. If CPU and GPU usage then decrease, the battery life indication will go up).
  • Reply 2 of 2
    Quote:
    Originally Posted by ryanbridgwood View Post


    Hi all.



    New to the forums, and only had a mac for three months, so I hope i'm welcome!



    Erm, for the last few days i've been worrying about my battery, I know it's silly and everything, but it's supposed to have 7 hours. It will go for a good 5 hours, sometimes more than that. But the percentage rate seems to be going down quite quickly. e.g half an hour ago it was at 73%, now at 62%.



    The battery time also changes quickly, from 6 hours 42, to 2hrs 32, back up to 4hours, etc.



    I have checked the condition on Coconut Battery and it's at 100%.



    Have you calibrated your battery recently, i.e. fully charge, then fully discharge and recharge with 2 hours between each section?



    As Mr H. has pointed out, the time indication is based upon the current load placed on the battery. Load comes from the following;

    CPU usgae

    HD usage (especially standard drives)

    Memory access

    Display driving (the brighter you have your display, the shorter the battery life)

    Any sounds being played

    Optical drive usage

    Bluetooth (both just being turned on and actual usage)

    Wireless access (including what encryption is being used and how good your signal is. A weak signal boasts the output power and also requires more error correction on inbound traffic.)



    The two biggest though are CPU and display brightness.



    You can run activity monitor and close all windows of it excecpt the floating CPU usage. You will notice that if the bars are long for a long period, your estimated time will drop, whilst if they are low for a long period of time, it will increase.



    In terms of the 7 hours quoted by Apple, I believe that it can only be achieved in perfect wireless conditions (likely to be no encryption / error correction) with a very low screen brightness. I also think they didn't browse any Flash or Java on the internet as both can increase CPU usage considerably!!



    I typically get 5.5 to 6 hours usage on battery. It dropped about 20 to 30 minutes upon installation of Snow Leopard but I would expect service releases to increase this back to where it was with Leopard.



    Phil
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