Prolong health of macbook battery...

Discussion in 'MacBook Pro' started by cameronfield, Sep 13, 2009.

  1. cameronfield macrumors member

    Aug 11, 2009
    So I've got a few questions about ways to prolong the life of may new macbook pro's battery...

    1) How often should I fully charge/discharge?

    2) At what % should I plug in?

    3) At what % should I stop charging?

    4) If my MBP is 100% charged is it bad to keep using it while plugged in? Or is it better for the life of the battery to unplug it and let it get used?

    5) Any other tips/advice?

    Only reason I'm asking is because my 2 month old 13" MBP is already down to 90% health after only 32 charge cycles :(. What am I doing wrong?!
  2. cameronfield thread starter macrumors member

    Aug 11, 2009
    Thanks for the tip!

    Ok, so in this situation:

    "For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her MacBook Pro on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month. "

    So once it's fully charged should I leave it plugged in or unplug and let the electrons "move"?

    Example: right now in at home using my macbook. It's fully charged, and I'm leaving it plugged in. Is this good or bad for the overall health?
  3. cameronfield thread starter macrumors member

    Aug 11, 2009
  4. pharonyk macrumors member

    Sep 13, 2009
    I understand where you're coming from... but I have a specific question that I think will help us find out what we really want to know.

    Let's say I plan on using my laptop for at least 2 hours at home. At the start of the 2 hours, my laptop is charged at 100% and I decide to keep it plugged in.

    Knowing the fact that it's bad to not have the electrons moving in the battery, will the laptop even go through it's charging cycles/battery at all or will it just power the laptop like a desktop within those 2 hours?
  5. zoziw macrumors member


    Feb 19, 2006
    With my four year old iBook G4, I primarily used it plugged in but ran it off battery one or more times a week. It currently retains 61% of its charge and has about 250 cycles on it.

    I'd run it off battery power a couple of times a week to keep the electrons moving while minimizing the number of cycles you are using up.

    I'm not an expert on battery life though.
  6. SpaceKitty macrumors 68040


    Nov 9, 2008
    Fort Collins Colorado
    I had a Macbook that I rarely used on battery. It was mainly used on battery only when the plug would pull lose and sometimes I didn't notice till I got the warning that it was about to shutoff. It had 11 cycles on it when I sold it a year later. The new owner told me it wouldn't charge so I told them to take it to the Apple store since it had only 11 cycles. Apple store replaced it even though it was out of warranty due to the low usage.

    It's very important to let the battery run down every so often like mentioned above.
  7. cameronfield thread starter macrumors member

    Aug 11, 2009
    Thanks for the tips so far guys.

    I know most people on here say "just use it, who cares what the health meter says as long as you get good battery life" and that's true, but it's just really starting to worry me.

    After following some of the tips in this thread, mine jumped back up to 91%. Since then I've been charging it at 20%, then once it's charged leaving it plugged in for a bit, then using it, it's down to 89%...WTF?

    I've had this MBP for 2 months, for 35 cycles total...this is really frustrating :(.
  8. cameronfield thread starter macrumors member

    Aug 11, 2009
    I decided to start trying new things and watching the actual mAh reading instead of the health percentage.

    Today, when it got down to 20% I went ahead and plugged it in. Once it got within 10 minutes of being charged I unplugged it.

    I noticed the mAh reading went from 4898 to 4903.

    I guess I'll keep doing that in hopes that it slowly goes back up!
  9. Azathoth macrumors 6502a

    Sep 16, 2009
    LiIon (and presumably LiPoly) prefers shallow charge and discharge. I.e. don't keep the battery at >80-90% charge level whilst it is at high temperature. Keeping it at 100% and 40deg. C will cause permanent loss of about 30% capacity per year. That's why LiIon batteries ship from the manufacturer at about 40% charge - this is optimal for the battery shelf life.

    Similarly, try to prevent discharge to <15-20%, except when needed to reset the battery gauge.

    On my IBM Thinkpad I pop out the battery most of the time when i work at home (docked) or in the office - currently have 115 cycles in 2 years and about 95% of initial capacity. The utilities that came with this computer also allow you to set when to start charging, and, more importantly, when to stop charging the battery.

    The new battery technology in the MBP may mean the battery is less sensitive to the effects mentioned above, or that the controller chip on the battery has become smarter, to prevent the constant 100% charging. YMMV
  10. cameronfield thread starter macrumors member

    Aug 11, 2009
    Thanks for the advice! So is it better to charge it more frequently, with short charge times? Or is it better to charge it less frequently with longer charge times?

    And if I'm at home and it's charging and hits 100% and I'm going to be using it for another hour or two, should I leave it plugged in or unplug it and let the battery work some?

    I'm back down to 4886mAh btw :/. I got up to 4956mAh yesterday, not sure why it dropped by 60mAh :(. I've been doing a lot of reading on LI-on batteries and am learning a lot, but some of it is still confusing!

    Edit: Right after posting this it's back up to 4924mAh -____- so back up to 90% health. I STILL feel like that's low for a 2-month old macbook though...
  11. bcburrows macrumors 6502


    Mar 25, 2009
    New Battery stats

    Have another battery question.
    Just bought a brand new uMBP 15inch battery
    Had it charging all night as per apple instructions
    Am currently allowing it to run down, however
    Just ran coconut battery and discovered the following

    Battery Loadcycles: 3
    Current Battery Capacity: 4226 mAh
    Original Battery Capacity: 4600 mAh

    Now I realise that the batteries often arrive with a couple of loadcycles as they have been tested, but it the current capacity is 4226 and the original was 4600 (difference of 374 mAh approx 7%), this just seems quite a lot for a brand new battery.

    I will see what happens after it has been properly calibrated but I can not imagine the capacity is going to actually increase.....

    Thoughts please

  12. jsnuff1 macrumors 6502a

    Oct 4, 2003
    I wonder if there are any utilities for the mac to keep it from charging the battery beyond a certain charge level.
  13. cameronfield thread starter macrumors member

    Aug 11, 2009
    Wait, am I missing something?

    The 13" MBP has a 5500mAh battery while the 15" MBP has a 4600mAh?

  14. bcburrows macrumors 6502


    Mar 25, 2009
    Mine is the removable battery not the built in
    Also the uMBP reduced battery size

Share This Page