10 Replies Latest reply: Apr 1, 2009 4:40 PM by bechard
Steven Adamson1 Level 1 Level 1 (15 points)
When using the Air at home, is it ok to always leave the computer plugged into the AC adaptor, whether in sleep mode or in shut down mode? The magsafe plug on the computer stays green because the battery is charged. If I unplug the ac adaptor, even for a day without using the computer, the plug is first amber as some charging takes place.
What is the best way to use the computer at home to preserve battery operation over the long term?

Macbook Air Rev b, Mac OS X (10.5.6)
  • RonAnnArbor Level 4 Level 4 (2,705 points)
    You can leave it plugged in 24/7 if you want, and you will see no battery degradation. There is nothing you need to worry about to preserve the battery life. Use your MBA exactly like you would any other notebook computer, and enjoy it.

    For the past 8 years I have been using Macbooks, Macbook Pros, and now the MBA first gen and second gen for the last year, and I have never seen any battery degradation in any of my notebooks over the course of their very very active lives -- within a couple years I've upgraded to a newer model and the battery in the last machine has never shown more than a percentage point or two of degradation with 18 hours of use, 7 days per week for years.

    Don't worry about it, and enjoy your MBA. Plug it in when you want, Unplug it when you want. There is no routine that will change anything.
  • David Hirsch Level 1 Level 1 (0 points)

    Your experience defies the laws of physics. All rechargeable batteries lose the ability keep a charge due to chemical changes that happen within the battery each time it is discharged. I have replaced the battery on my 4 year old powerbookG4 twice because it could not hold a charge for longer than an hour. This is not Apple's fault ... it's just how batteries work.

    However, your answer is correct. Keeping your computer constantly plugged in is not only safe to do, it preserves the life of the battery ... something you MUST do to maintain the useful life of your MBA.

  • RonAnnArbor Level 4 Level 4 (2,705 points)
    You will note that I mentioned that I have never kept a Mac portable for more than two years before upgrading...during that time I have never seen any degradation beyond a couple percentages...sorry about your experience...
  • Soft Reset Level 4 Level 4 (1,790 points)
    Some other users already hit on the main points...

    One thing worth mentioning, the purpose of the MacBook Air was to be super portable and I'd imagine for the typical user who purchases the machine they're anticipating being very mobile with it. I know on mine, I've already crossed the 100 charge cycle threshold and the machine is only about 3 months old. I use it a lot, both plugged in at night and unplugged during the day.

    No matter how you use your battery, charge the machine, or leave it plugged in, ultimately the battery's longevity will be depleted. There are ways to prolong it, but it's impossible to prevent it. My advice to you, is to use the machine how you see fit.

    Regarding charging at night, there's no evidence to support that leaving the machines plugged in overnight (on, off, sleep or otherwise) is problematic. I personally unplug mine at night, unless it requires charging. But again, that's a personal preference.
  • emilcar Level 1 Level 1 (10 points)
    When I am working at home with the AC adaptor plugged, and the light turns green, after 10 or 15 minutes the temperature starts growing and the fan starts running a 6200 rpm. If I unplugg the AC adaptor, the fan goes 2500 after a couple of minutes
  • Soft Reset Level 4 Level 4 (1,790 points)
    Hi emilcar,

    Interesting. When the LED goes green, it's switched to what's called "trickle" power where there should be minimal heat generation. You're not really charging the battery at this point, the adapter is pretty much just keeping the battery topped off.

    Are you using the machine when this happens or is it sitting idle?
  • RonAnnArbor Level 4 Level 4 (2,705 points)
    The previous poster is also running off of a different current than here in the US...while theoretically it shouldn't make a difference, we can't really comment on that -- how does the MBA work on AC vs DC current...perhaps an engineer can comment, or someone else from Europe can comment...but I am not sure us US users will be able to really help with this one.

    Like with all Apple questions, if you are concerned that something isn't working right, make sure that Apple takes a look at it.
  • HyperNova Software Level 6 Level 6 (8,530 points)
    It makes no difference what country or voltage.

    The Apple Magsafe power supply converts whatever it is to the same voltage at the Magsafe end.
  • emilcar Level 1 Level 1 (10 points)
    Hmmm, after reading your posts and other forums I was thinking in my problem and I tried to do something different. After all, I have assumed that the plugged cable was not the problem BUT the proximity of the table with the rear side of the MacBook Air.

    I went to the local APR and bought Tucano "Fresko Gel", soft technogel feet designed to be placed under the notebook to enhance ventilation and heat dispersion.

    After many hours working with this "new configuration" under the desk and under my Belkin CushTop, I can say that my problem has been resolved (but now I feel a bit stupid for my first post)
  • bechard Level 1 Level 1 (0 points)
    " You can leave it plugged in 24/7 if you want, and you will see no battery degradation. There is nothing you need to worry about to preserve the battery life. "

    Not according to Apple via: http://www.apple.com/batteries/notebooks.html March 2, 2009

    "Standard Maintenance
    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. Need a reminder? Add an event to your desktop’s iCal."