Rapidly climbing cycle count on battery...

Discussion in 'MacBook Air' started by petestein1, Mar 26, 2008.

  1. petestein1 macrumors member

    Feb 8, 2008
    So first off, I absolutely LOVE my MBA. Now that we have that out of the way...

    Since day 1 I've noticed that the cycle count on the battery seems to be climbing MUCH faster than it should.

    -- I've had the machine 51 days. I was out of the country without it for 9 days so really, I've had it for 42 days.

    -- According to iStat and System Profiler my battery's cycle count is 37

    -- According to System Profiler my battery's health is "Good"

    -- According to iStat my battery's health is at 98% (It started around 96%, has been as low as 94% but seems to have settled in at 97 or 98% for some time now)

    -- According to system profiler my maximum charge is 5006 mAh. (It's also gone up a bit since the machine was new).

    I thought the definition of a cycle was the equivalent of 100% depletion of the battery -- whether that's one long unplugged stint that sucks it dry or 10 really short ones -- a cycle is the same as using ~5000 mAh of battery power.

    So here's the thing. I've been REALLY good about keeping it plugged in while I work (the outlet is conveniently located). I've run the battery most the way down maybe 5 times. I do, however, run it down 10 or 20% almost every day as the machine travels with me in sleep mode or spends the night unplugged in sleep mode at my girlfriend's place)

    I haven't done any careful testing but it seems though that if I run the battery down just 20% or 30% or so and then charge it all the way back up the cycle count increases by 1.

    Considering I've only used it for 42 days, and the cycle count is already at 37, I'm worried that it will hit 200 cycles by the time it's 8 or 10 months old. Isn't the point where battery performance starts to wane?

    Anyone else out there notice a rapidly climbing cycle count? Any suggestions or ideas?

    Oh yeah, and I love my MBA. ;)
  2. mac jones macrumors 68040

    Apr 6, 2006
  3. aristobrat macrumors G5

    Oct 14, 2005
    I've noticed the same behavior with my MBP over the last year that I've had it. Even if I only drain the battery a little bit, when I hook it back up to the charger, it shows as a cycle.

    The only thing I can think is that the way the battery counts cycles is "everytime it's plugged into the charger, that's a cycle".

    When Apple says a battery is supposed to have 80% of its charge left after 300 cycles, I think they mean 300 full discharges/recharges.

    In the end, I agree with mac jones ... don't worry about it. At least, not too much. :)
  4. UltraNEO* macrumors 601


    Jun 16, 2007
  5. petestein1 thread starter macrumors member

    Feb 8, 2008
    I haven't calibrated it yet. I keep meaning to get around to it and my days keep filling up.

    I'll try to do it next week though I doubt that would make a difference.

    Keep in mind, my battery performance is pretty good. I started today with a full battery and then spent 2.5 hours working off of battery (wifi off mostly, just working in MS Word). After 2.5 hours of work it said I still had 2 hours of battery left and I bet it would have lasted 3 hours, not 2.

    Proving my original point though, after draining the battery 40% today the cycle count increased to 38. :-/

Share This Page