late 2008 mbp short battery life

Discussion in 'MacBook Pro' started by lensflare, Oct 18, 2010.

  1. lensflare macrumors newbie

    Joined:
    Oct 18, 2010
    #1
    First post here, after doing a lot of research I decided to tap the brains of the experts.

    I have the 15" late 2008 unibody mbp with Penryn P8600 CPU and switchable GPU. I got it as a refurb and have owned it for little more than a year, and during the entire time I have never been able to get more than 2-3h of battery life out of it. Contrast that to the tests and users here reporting up to 5h. Here is a chronological list of things I have done to figure out what's going on:

    • Upgraded to Snow Leopard 10.6, hoping it has better Battery mangagement
    • Got the entire lower case replaced on Applecare, Logicboard was fried
    • Bough a new battery, old on was giving "Service Battery" warnings
    • Just the other day installed a fresh copy of Leopard 10.5 on a separate partition to make sure there is absolutely no software running in the background

    I am using MiniBatteryLogger to monitor health, which is good, and battery current, which is alarmingly high. I also gave CooBook a shot, but only in the Freeware demo mode, where it shows me that my CPU is running at the lowest possible clock speed of 1.6GHz when idle, which seems OK.

    Still, even when the machine is completely idle, bluetooth and WiFi off, brightness way down, and only a single browser (no flash) or PDF document running, I don't get more than 3h where I should be getting 5h or more. In a more typical situation with medium brightness, Wifi, email, iTunes and a couple of documents open, I am immediately down to 2h, and if I switch on the 9600m GPU and do some processor heavy stuff, I can burn through a battery in little more than 1h.

    As I said I already did a lot of research and consider myself fairly knowledgeable in all things Mac, so I guess this is more of a rant than really hoping for a solution. In fact I am beginning to resign myself to the possibility that I' just have to pick up an iPad for the two or three international flights I do every year, rather than trying to squeeze an extra hour out of the mbp. Still, any information would be appreciated.
     
  2. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #2
    Is that actual battery life until it shuts down, or battery life as indicated by MiniBatteryLogger? I'm not familiar with that one. Most use iStat Pro, iStat Menus or coconutBattery.

    Have you calibrated your battery? How often do you run on battery, and how often are you running plugged in?

    This should answer most, if not all, of your battery questions: Apple Notebook Battery FAQ
     
  3. iLog.Genius macrumors 601

    iLog.Genius

    Joined:
    Feb 24, 2009
    Location:
    Toronto, Ontario
    #3
    There's nothing wrong with your battery or your computer. With your usage, you should get anywhere from 2-3 hours with constant usage (and you seem to get that) and 4-4.5 hours with on/off usage. You'll never get anywhere near the advertised time of 5 hours.
     
  4. SBA macrumors member

    Joined:
    Aug 10, 2008
    #4
    I've got the same model computer as OP and am seeing similar battery results. I don't recall seeing anything about the battery being rated better than 3 hours, which is about what I can get using the 9400m with normal usage (web browsing, twitter client, etc.) As far as I'm concerned it's not too bad. I remember when the models after this one came out, the battery was integrated and was rated for longer run times.
     
  5. uMBPi728 macrumors member

    Joined:
    Nov 19, 2010
    Location:
    Glendale, Ca and Berkeley
    #5
    MiniBatteryLogger is a very useful tool. I've been using it now for about a week and seems to give me a good indication of how long I've been on battery power. If you're at all interested in how long you're battery is lasting between charge then MiniBatteryLogger will display that info for you along with other metrics.
     
  6. RKpro macrumors 6502

    Joined:
    Oct 27, 2008
    #6
    I think 2 hours is a bit low, but if you're getting about 3 with a healthy battery, it's normal.

    I have the same model, and yeah, it's got a pretty small battery.

    Mine is at 92% health, and I can get about 3.5 hours of normal usage. Half screen brightness, wifi on, no bt, no keyboard lights. Mostly web browsing (with adblock plus), and productivity software.

    I did manage over 5 hours once, when the computer was new, but I was writing a paper in MS Word and viewing PDFs, occasional wifi usage and 1/4 brightness.
     
  7. aimbdd macrumors 6502a

    Joined:
    Dec 10, 2008
    Location:
    East Cost
    #7
    Mine will last 4 and a half hours with just text edit open typing notes ;)
    Otherwise... no such luck.
     

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