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I try to buy an old mac book pro mid 2012. Old user of this mac uses mac by electric all the time, so the life cycle till now just 3 cycles, but this computer has been used for 1.5 years.

My question is: if this mac is only 3 cycles, does this mean the battery still as good as new mac ?

Thanks :)

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I can speak from experience that the battery from by 2011 MBP 13' died (like only 10% of designed capacity left) after 56 cycles. It met a precipitous decline after a certain point. You may want you weigh your risk on the cost of replacing the battery.

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In my experience one of the worst things for a battery is to leave it plugged in and not cycle it. After doing this for a few months most batteries seem to become useless, sometimes not even keeping a charge for 5 minutes.

  • How come that is a problem? – Ruskes Sep 26 '14 at 0:20
  • I honestly don't know, but that's been my personal experience. an otherwise good battery a year or so old, leave it plugged in for a few months and it becomes next to useless. – Bill K Sep 26 '14 at 16:16
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There are 3 main factors that age a battery.

One is of course the constant charging and discharging.- the more the faster.

Second one is less know and it is the shelf life. Even if you do not use a battery it will eventually die due to the internal currents / shelf life.

Third and worse is Charging at all times in a elevated temperature environment.

In your case based on standards the battery is about 1/3 of its life based on age.

Suggested reading material to learn more about batteries.

  • You forgot to mention heat. – Bill K Sep 25 '14 at 23:46
  • @BillK you are right, I was assuming room temp. – Ruskes Sep 26 '14 at 0:19
  • @Buscar웃 and I have tested as you said, battery might go about 1/3 of its life. now it just works for about 5 hours if simply browse web :) – hqt Sep 26 '14 at 20:05
  • @Buscar웃 can you tell me. I read some links. here for example, wired.com/2013/09/laptop-battery so, do we always try to put battery from 40% to 80% ? (so, when battery is down under 40$, i will charge until 80%, and unplug and continue to use) Thanks :) – hqt Sep 26 '14 at 20:06
  • If you have OS 10.9 and above open the Activity monitor then the Energy tab, there is a lots of information of interest. My battery on a MacBook Air last about 4-5 hours max, mainly using the Browser, no movies ect (sound off), Brightness (the biggest consumer) to lowest acceptable levels. – Ruskes Sep 26 '14 at 20:31

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