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I recently got the new MacBook Pro 2018 and would like to look after the battery better as I need it for university and would keep it for at least 3 years.

I understand that they are lithium-ion batteries and have a recommended max cycle counts of 1,000. A cycle count is counted as charging it x%, discharging x% and charging x% (if I remember).

If I were to keep the MacBook Pro on permanent charge, I will not have any extra cycle counts. However, would this cause any damage to the computer or not? I also think I read somewhere (a few years ago) about batteries breaking in (just like an engine). If this does happen, how long would this take?

If it helps, I have the 15".

iProgram
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1 Answers1

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These days, keeping your laptop plugged in as much as you like isn't going to make a significant difference to the battery life. The Li-ion batteries in modern MacBooks don't need calibrating, they don't suffer from the "memory" problems that NiCd batteries did, and when they hit full charge, they just allow the battery to drain by a couple of percent before trickle charging back up to 100% again.

Apple's most recent battery health tips can be found here: https://www.apple.com/batteries/maximizing-performance/

calum_b
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  • When reading the info on that link, it says "Conversely, if you store it fully charged for an extended period of time, the battery may lose some capacity, leading to shorter battery life." Does this mean that leaving it fully charged mean that the battery would loose capacity over time? Or is this 'normal' use? – iProgram Jul 30 '18 at 10:05
  • This only applies if you're storing the battery for some period of time. In normal use, the MacBook prevents the battery from staying fully charged for any length of time, by disconnecting power for a while, then re-connecting it. (You won't be aware this is happening, the battery indicator will show '100% and charging' the whole time.) – calum_b Jul 30 '18 at 10:17
  • Also, lithium ion batteries suffer greatly when all charge is removed. So for prolonged storage, keeping them at 25-75% charge is ideal. On the other hand, always plugged in brings on heat issues. Apple power cords will eventually fray and if the computer doesn’t sleep and hangs on processing a task it will overheat. Suffice to say, there are potential fire hazard for leaving a device plugged in and unattended. – vol7ron Jul 30 '18 at 13:47
  • @vol7ron True, the Apple page recommends storage at 50%. – calum_b Jul 30 '18 at 17:24