Want MBA power cord w/o charging

Discussion in 'MacBook Air' started by JesseW6889, Dec 12, 2010.

  1. JesseW6889, Dec 12, 2010
    Last edited: Dec 12, 2010

    JesseW6889 macrumors 6502

    Dec 12, 2010
    I was reading in an online article about 3rd parties that have been creating external battery backups by splicing them with original apple magsafe adaptors.

    In the same article I read that some company had created their own magsafe type adaptor for the same reason, but that it didn't violate Apple's patent because the 3rd party adapter could only power the MBA, not charge it.

    My question is, if something like this (2nd paragraph) exists, wouldn't it be better to use in a situation where my MBA is at a desk, plugged in most of the time, so that the battery isn't degraded?

    Let me reiterate a little bit, wouldn't it be better to have an AC adapter power cord (NOT Battery Pack as mentioned above) to keep your MBA powered on, without involving the batter?

    For now, I am leaving my MBA in till it's charged, then unplugging it until its discharged, repeat. Its kind of a pain as I end up doing it several times a day, and occasionally when I need to go somewhere, the battery isn't charged (as its in the discharge cycle).

    Anyone have any information on this?
  2. alust2013 macrumors 601


    Feb 6, 2010
    On the fence
    Why don't you just leave it plugged in when it is charged? Constantly charging and discharging is not particularly good for the battery, especially several times a day. When it reaches full charge, and the light turns green, it will no longer charge the battery. It will not charge the battery until it is used down to about 95% charge, so it is perfectly fine to use it while plugged in.
  3. JesseW6889 thread starter macrumors 6502

    Dec 12, 2010
    I guess that makes more sense! I'm new to Macs (Read: New to things making sense)
  4. BeyondtheTech macrumors 68020


    Jun 20, 2007
    Funny you should ask this. I just bought a non-genuine AC charger/adapter for my MacBook Air 11.6" from eBay and received it early last week. For $10 including shipping from inside the US, I figured it would be great to leave at home and bring the smaller, genuine one around when I'm on the go.

    Unfortunately, it would not charge my Air, only power it.

    System Profiler showed this for Power:
    AC Charger Information:
    Connected:	Yes
    ID:	0x0000
    Wattage (W):	0
    Revision:	0x0000
    Family:	0x0000
    Serial Number:	0x00000000
    Charging:	No
    Looks like there's specific communication through that little MagSafe connector. Is my MacBook too smart or keen to allow it to be charged by a non-Apple or non-Apple-certified product?

    Needless to say, the eBay dealer, mambate, credited me back $10 and didn't ask for it back.

    Still on the lookout for a less-expensive AC charger/adapter...
  5. JesseW6889 thread starter macrumors 6502

    Dec 12, 2010
    I might be in the market! Honestly, I don't think the battery is even used once it is fully charged (while remaining plugged in). The general consensus seems to be that, once fully charged, the charger stops charging, and the macbook is run by the internal battery until it drops to 95%, at which point, the charger turns back on and charges it to 100%, repeat.

    In practice, I'm pretty sure my MBA is running on AC power after the battery is charged... at no point does the charger 'turn back on' nor does the battery drop to any % below 100... or is this possibly going on in the background without my knowledge? If this were the case, when unplugging the power cord, I should at *SOME* point, catch the power supply somewhere between 99 and 95% but every time i unplug it, it is at 100.

    Is it confirmed thats how old MacBooks run? Is this possibly a new thing for the new air's or is this standard for all of them?
  6. Mike84 macrumors 6502a

    Jun 23, 2010
    Hey, I read your statement and I was curious if you could expand on that. Are you saying it is bad to let a battery drain itself and then to be charged? Doesn't Apple recommend people to let the battery drain until it is dead so that you can cycle the battery?
  7. fjk, Dec 12, 2010
    Last edited: Dec 12, 2010

    fjk macrumors regular

    Jun 9, 2008
    When your battery is plugged in > 95%, the AC powers your laptop exclusively to preserve the battery.

    The battery is therefor left idle, without powering your laptop. Over time it will discharge on its own. It will not be re-charged until it drops below 95% due to idle discharge.

    This is to prevent it from constantly being recharged each time the battery lost some of its charge, or if you unplugged it for a second or a minute and replugged it back in. This avoids needless charge cycles.

    When plugged in at 100%, bc the battery is not in use, it will only discharge very, very slowly. Which is why you probably never or rarely see it dip below 100% when it is idling on AC.
  8. fyrefly macrumors 6502a

    Jun 27, 2004
    The key thing is to also let your battery go through one full charge cycle a month. Especially if you are always using it plugged in.

    Apple recommends letting the computer get 100% charged for 2-3 hours and then using it till it shuts itself off (after the "You are Now Running on Reserve Battery power" warning). Then leave it "Dead" for 5+ hours and then charge it up completely again.

    You should make sure this happens once a month and otherwise not worry too much about how much your laptop is plugged in or not plugged in.

  9. JesseW6889 thread starter macrumors 6502

    Dec 12, 2010
  10. GGJstudios macrumors Westmere


    May 16, 2008
    It is NOT recommended that you run on AC Power without the battery installed.

    This should answer most, if not all, of your battery questions: Apple Notebook Battery FAQ

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