what is the secret to good battery health?

Discussion in 'MacBook Pro' started by bchamorro, Feb 22, 2010.

  1. bchamorro macrumors regular

    Dec 31, 2007
    I've heard it is bad to let it discharge completely. What is the secret to good battery health?
  2. MrCheeto macrumors 68030


    Nov 2, 2008
    The secret is, use it or lose it.

    You have to put some sort of load on the battery and then charge it back up to keep it in good condition.

    Leaving your computer plugged in for eternity will just let the battery waste away.

    Ni-Cd batteries have what's called "voltage depression", meaning they lose capacity the more you use them. We use Lithium batteries these days, which don't have this effect, however, like all batteries, need to be charged and discharged to remain healthy.

    At least once a month, drain the battery completely and recharge it. I have heard of people using their original iBook batteries from about 2000 with about 30 minutes to an hour of use at best, and those were Lithium-Ion, an old cell composition.
  3. Alvi macrumors 65816


    Oct 31, 2008
    Don't have it plugged in all day, after that plug it out 30 mins, plug it back in, after some hours again and so on, if you plug out your computer drain it, especially if you rarely do that, while travelling turn the backlit level as low as you can and turn of automated sensor features which use more battery, sometimes it can give you more than what apple claims, especially if you're just writing text on a plane or something like that

    The main thing is being ok with it, accepting that it will perform worse in 2 years and so on, The secret for any product satisfaction is enjoying it without having to be super careful with it, like having a super thick case on your iPhone and so on, use the battery as it's comfortable for you as long as it lasts, then replace it, they're not that expansive for the satisfaction it will give you, sorry for offtopicing btw
  4. Batt macrumors 65816


    Dec 17, 2007
    Syracuse, NY
    I leave mine plugged in 99.9% of the time. Once in a blue moon I decide to let the battery drain. I've done this maybe 4 times in 2½ years, and the battery still shows a 99% charge and still shows up healthy in System Profiler.
    There is no standard answer, it all depends on how you use your laptop.
  5. bsizz234 macrumors member

    Jan 25, 2010
    mine shows a 100% charge when it's done charging. problem is that now 100% is only 48% of what it used to be.

    time for a new battery for the second half of the computer's life...
  6. dehory macrumors regular


    Sep 17, 2008
    Both of these points are incorrect.

    The most well-reasoned and definitive response to this question that I've seen is from iLounge. Obviously what applies for a 2008 iPod battery applies for the newer generations of Apple portable computers.

  7. m85476585 macrumors 65816

    Feb 26, 2008
    But most people aren't leaving their ipods plugged in 24/7.

    Storing a battery at 100% charge is bad for it, and is essentially the same as leaving it plugged in 24/7.
    As you can see in the first table on this page
    A battery stored at 100% charge and 40C may drop to 65% health after a year, as opposed to 85% for one stored at 40%. A battery in a laptop will do better than that since it gets used at least a tiny bit, but the point it leaving the battery at 100% all the time is bad for it. Discharging and recharging the battery, at least partially, refreshes the chemicals inside and prevent the health from dropping.

    In short:
    -Using the battery regularly is good
    -Try to keep the computer cool. Don't run it on a blanket, and don't leave it on 24/7 if you aren't using it.
    -A full discharge until the computer shuts off is not necessary except to calibrate the battery life meter.
    -Don't worry about the battery and it will probably be OK.
  8. applesupergeek macrumors 6502a

    Nov 20, 2009
    Wait a sec guys, surely if you use your battery more frequently than others, that will decrease it's life cycle. So you might need to occasionally unplug your mac, but I don't know if you mostly unplug it and let the battery drain to a certain point if you are helping anything, apple has made it clearly there are certain finite charge and discharge cycles.
  9. m85476585 macrumors 65816

    Feb 26, 2008
    If you have one that is rated to last 1000 cycles, it will last 3.8 years if you use 1 cycle per weekday.

    I leave my laptop plugged in most of the time, and I'm already on my third battery (mine is older and the batteries are rated for 300 cycles). Both batteries had right around 100 cycles on them when they were replaced, and they were both a bit less than 80% health (the point at which Apple will replace it). Using the battery will decrease the life, but that doesn't mean not using it won't decrease the life (triple negative). Basically, batteries have a finite life no matter what. If you don't use it, you will shorten the life, and if you use it excessively (multiple cycles per day), you will also shorten the life. Moderate use seems to be best.

    With this battery I've started keeping it cooler and using the battery more. I run SMCFanControl at 3K RPM all the time, I have an aluminum cooling pad that keeps the CPU 10C cooler, and I put the computer to sleep at night instead of leaving it on 24/7. I am trying to intentionally use it on battery more, but I still don't do that much because I am forgetful.
  10. ARF900 macrumors 65816


    Oct 30, 2009
    The secret is to just use it however you want, however if you are going to leave it plugged in 24/7 Apple does recommend you calibrate the battery once a month to keep it in good health for that time when you really do need it.

    But why buy a notebook just to leave it on a desk all the time?
  11. SDub90 macrumors 6502a

    Nov 9, 2009
    Long Island
    I completely discharge my macbook once a month at least, typically keep it plugged in all the time when I'm using it if I can and unplug it if it's at 100% when i put it to sleep. If I'm storing for over a few days without expected use (ie I go away and leave it home) I drain it to roughly 70% and leave it sleeping and unplugged.

    You want to avoid:
    -Going through an excessive amount of full cycles
    -Frequent short discharged (charging to 100%, discharging to some lower % like 30, 50 or 80, then charging to 100% and repeating)
    -Keeping it fully charged all the time
    -Only using the battery for short periods of time

    My first macbook battery lasted 2 3/4 years and lasted 4 hours before I started to go through several cycles a day for 6 months, after those 6 months it went down to 2 1/2 - 3 hours. Had the battery replaced and a year later I still get 4-4 1/2 hours depending on my usage.
  12. w00t951 macrumors 68000


    Jan 6, 2009
    Pittsburgh, PA
    Trust me: 15 laptops of experience.
    The new lithium batteries don't require a full discharge to remain healthy. If you take enough time and peruse the Apple article it says that the purpose of cycling the battery is to make sure that the battery percentage indicator is accurate. By completely cycling the battery you take one charge cycle. Around 1,000 charge cycles, your battery capacity will be greatly diminished. The secret that I've found to keeping your battery healthy is to try and keep down the number of cycles. One cycle is about 50-100 percent of the battery's capacity.
  13. kbt1020 macrumors regular

    Feb 15, 2010
    So usually, is it good to shut down the mbp? sleep w/ it plugged in or unplugged?
  14. m85476585 macrumors 65816

    Feb 26, 2008
    Shutting it down/sleeping keeps it cooler, which can't hurt the battery. I don't think it really matters much if the cable is plugged in or not while it is asleep.
  15. mikes70mustang macrumors 68000


    Nov 14, 2008
    the secret is reading the hundred other threads about how to have good battery life.
  16. Saturn1217 macrumors 6502a

    Apr 28, 2008
    Ugh I hate reading these battery care threads. I always end up more confused than when I started.

    I don't mean to be rude but in your list of what to avoid you basically just list all the possible ways I can think of to use (or not use) the battery. If this is what you shouldn't do then what are you supposed to do?!

    I only ask because my battery capacity (as measured by system profiler) seems to go down every time I use it. At first I tried only partial discharges but that was not so good and now I'm trying longer discharges but it's still dropping more than I'd like. I definitely don't feel like I'm getting the benefits of the built in battery on the new uMBPs :(
  17. ammusk macrumors regular

    Oct 20, 2009
    Discharging it partially hurts. Always try to do a full discharge and consequent full recharge.
  18. MacGiver macrumors 6502a


    Aug 12, 2007
    Sharing my experience here. I bought a MBP end of 2007. I most of the time use it at home and left the MBP plugged on the mains...result is that after a short time the battery died after 10min whenever i used it unplugged.
    My wife left did the opposite with her black MB...result...the battery is still in very good health!

    Conclusion: never ever leave your laptop on the mains all day long! My laptop simply became a desktop...lesson learned for me as i plan to buy the incoming 13" MBP and sell my old one (of course with a brand new battery)
  19. jjahshik32 macrumors 603

    Sep 4, 2006
    My routine involves in leaving the mbp plugged in at all times at home and only use the battery when out and about.
  20. jjahshik32 macrumors 603

    Sep 4, 2006
    I honestly believe that it was a special case for your 2007 mbp. Iv actually heard the opposite that keeping the mbp plugged in is better than to continuously uncharging and charging the battery.

    I know that once in a while it is good to completely discharge the battery and fully recharge.
  21. SDub90 macrumors 6502a

    Nov 9, 2009
    Long Island
    Doing the things in that list frequently will drastically shorten battery life. Everything you do with the battery will shorten its life in some way - some greater than others. My day is pretty routine and I'm always near a power outlet, so it's very easy for me to find the right balance of battery usage to have it hold its charge much longer than most people, but the techniques I use nearly defeat the purpose of having a laptop.

    The most important things are to have at least 1 full discharge each month and to not unplug the charger and drain the battery as soon as it hits 100%.
  22. Gomff macrumors 6502a

    Sep 17, 2009
    Part of it is luck of the draw.

    I have a late 2006 Macbook pro. Apple replaced the battery on it about a year and a bit ago, after I complained that it had only had 46 loadcycles and was running below 80% efficiency. The one I have now is much healthier - 57 loadcycles and 93% efficiency according to Coconut battery. When I got the battery it was 98% so it hasn't dropped too much.

    Usage wise, it's plugged in at my desk most of the time but I usually bring it to the front room to surf in front of the TV a few times a month in the evening, so it gets some usage. I can get about 3 hours out of it surfing, with the screen dimmed to about 40%.

    Conversely, a buddy of mine has a 3 year old Macbook - his battery has about 180 loadcycles and still reads 91% efficiency. He uses it just on battery power a lot and maybe that has something to do with it's great performance. Equally my 2G iPhone will regularly run for 5 days in between charges and seems to show no evidence of wear and tear in the 2 and a half years I've had it.....I think I got lucky with that battery though.

    I still think it's a combination of reasonable usage and getting a lucky break.
  23. Dan73 macrumors 6502a

    Jul 30, 2009
    Use the battery for a few days and report back then
  24. mrsir2009 macrumors 604


    Sep 17, 2009
    Melbourne, Australia
    When I'm using my MBP I never have it on the charger. I use it for quite long periods, and when I'm finished with it there is usually about 20-40% battery left. When I'm not using it its on the charger, so when I go to use it its full (or almost full). This method ensures the MBP gets nice deep battery cycles:D

Share This Page