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fully charge then drain battery? or keep plugged in?

Discussion in 'MacBook Pro' started by charlestrippy, Jun 21, 2006.

  1. macrumors 6502


    I'm curious:

    What's the best way to keep your keep in good order...

    should you fully charge it than drain it or should you try to keep it plugged in most of the time?

    I ask this because in a month's time my battery (according to coconut battery) went from 100% capacity to 96% in ehhh, 20 days i think?

    At this rate, i'm going to be "hurting" down the road hah

    any suggestions?
  2. macrumors 6502a

    i always thought that you should charge, drain, charge your battery since overcharging a battery is bad. At least with the iPod (and cell phones) you should do this to prolong life. but, a lot of people use their notebooks plugged in all the time and there doesn't seem to be a problem, but maybe thats just because their plugged in all the time...
  3. macrumors 6502


    I think the official word from Apple is charge...drain...charge once a month or so to properly calibrate the thing. My only problem with this is that fully discharging lithium ion batteries is not good for them. Give it a try, but don't do it all the time.
  4. macrumors 6502



    so i should main draink it to about 50-60% and than start charging it again....then about once a month drain it fully?
  5. macrumors regular

    I think it's different for different models. I know the iBook was just drain it all the way down then recharge. My MacBook is a much more involved process of charging, using it for awhile, letting it drain, letting it sit for at least five hours, and then charging it up.
  6. Moderator


    Staff Member

    To prevent the battery to go into an endless charge -> discharge -> charge loop every time the battery goes below 100% (since a typical lithium based battery has a lifespan of about 500 charge cycles), Apple has set it not to start charging before it dips under 95%.

    Apple - Batteries - Notebooks
    Apple - Batteries

    You can find information on your battery's performance in System Profiler -> Hardware -> Power.
  7. macrumors 6502



    thanks dude!
  8. macrumors 6502


    You don't have to fully discharge your iPod before you charge it again. And I believe new cell phones follow the same rules. Where before you had to fully discharge your phone, it doesn't matter if you charge it when it's at 80% now or whatever.

    As for the MacBook. It's recommended you calibrate it once a month and that's it.
  9. macrumors 68030


    i get yelled at by my fiance (in jest) because i always run to a charger when i hit 20%.. apparently, lithium ion batteries will start to "learn".. what i mean is, if that last 20% of cells are never used, then they will "learn" they're not used, and eventually stop holding a charge... so i don't know if always going to 50-60% and then charging, other than that one time a month that you drain your battery, is such a good idea, either...but perhaps someone else here may have more expertise to lend?
  10. macrumors 6502


    According to the Apple battery website:

    edit// I just checked the Wikipedia entry on Li-on batteries, and it also states that they have no memory effect.
  11. macrumors 6502



    any idea why in 20 days my capacity level went from 100% to 96% according to coconut battery than maybe?
  12. macrumors 68030


    sweeeeet.. i was able to yell (in jest, again) at my fiance for feeding me BS this whole time! thanks for the info :D

    his response: "er.. crap. what was i thinking of this whole time then?" heh

    ....it's the little things. :rolleyes:
  13. macrumors regular

    Yeah... Lithium-Ion proccessors do not have the memory effect, but fully discharging them can damage them (it's hard to fully discharge a LiIon battery because they have a microproccessor inside that shuts off your computer/phone/ipod). But if a device turns itself off due to low battery and you keep turning it on to try and get a few more minutes/seconds out of it, thats bad.
    It's the old NiCd and NiMh batteries that suffer memory effect.

    Also again, it is not possible to overcharge your MacBook battery (and most other devices that use Lithium Ion batteries) because the microproccessor inside them stops the charging once they are at full capacity. Same applies to iPods.
  14. macrumors 6502

    it hasn't. as the earlier poster said, to avoid using up precious charge cycles, the battery does not charge until it dips below 95%. and for some reason it doesn't always charge to 100% either. anyways, you are good, your battery is fine.

    also, i used to think about discharging my battery and then recharging, but i read about it and learned that i shouldn't do that.

    your battery has a certain number of charge cycles (ie. use 70%, charge 40%, use 30%, charge 60%, this qualifies as a charge cycle) and to drain your battery more than necessary will reduce the number of remaining charge cycles you have faster than you need to.

    look up the proper way to calibrate your battery, and do that how ever often it says to do it. other than that, if you have access to an outlet, plug it in. it won't overcharge. batterys and their chargers have made great advances over time and overcharging isn't something you have to worry about with most new equipment.

    plus, if you plug it in, your processor will run at a higher level, because it doesn't have to worry about conserving battery.
  15. macrumors 6502



    killer - thanks everyone for the imput!
  16. macrumors newbie

    i was also wondering whether i should always keep it plugged in. Ive had my macbook for a week now and its already down to 97% with 8 cycles...is this normal? how can i get it back up to a 100%?

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