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I can connect external monitor to macbook via type C port. But the battery starts charging when I do so.

This causes the laptop to always be charged at 100% (which is not good for battery life)

How do I avoid this charging when the monitor is connected to laptop?

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  • 1
    My workaround is to unplug the laptop after work. Use a script to consume some battery before allowing system sleep.
    – amdyes
    Commented Mar 15, 2019 at 9:02
  • @amdyes Where can I download that script?
    – Vahid Amiri
    Commented Apr 18, 2019 at 14:26
  • @VahidAmiri You don't need, there is a builtin command caffeinate, just run caffeinate -i.
    – Daniel
    Commented Jun 25, 2019 at 12:50

3 Answers 3

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I spoke with Apple chat support. They did not have a solution for this issue.

My tested and working solution is as follows:

I bought 2 things

  1. HDMI Cable (one end connected to external monitor)
  2. USBC to HDMI converter (one end connected to macbook)

Now, the macbook does not charge because of external monitor connection.

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  • So if the Macbook is at 50% (for example) when you plug in the HDMI cable, does it stay at 50%?
    – Bataleon
    Commented Jul 1, 2019 at 9:42
  • @Bataleon yes. it is as if there is no charging cable
    – xxx374562
    Commented Jul 6, 2019 at 13:50
  • That's really good news. Lithium-ion batteries hate being kept at a high state-of-charge + high temperatures. I'm glad Apple have finally come up with a solution.
    – Bataleon
    Commented Jul 8, 2019 at 8:39
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    @Bloke It's difficult to say exactly how significant, but for example, charging a lithium-ion cell to 4.1v instead of 4.2v (usually seen as "100% charged") will result in double the cycle life of the cell. There's an excellent talk on YouTube titled "Why do Li-ion Batteries die ? and how to improve the situation?", presented by Prof. Jeff Dahn (world renowned battery chemistry expert currently working for Tesla) which I urge you to watch. He provides lots of interesting data in his presentation.
    – Bataleon
    Commented Aug 5, 2019 at 8:56
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    @Bloke There is some hard research here as well: accubattery.zendesk.com/hc/en-us/articles/…
    – dlsso
    Commented Mar 4, 2020 at 19:46
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Use Apple's optimized charging feature. This may not have been available when the question was originally asked but anyone with a similar concern has this as an option today. (That is unless Apple changes things again in the future.)

Apple documentation on the feature is here: https://support.apple.com/en-us/HT212049

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Try the AlDente app.

There's a free version which has the features "Charge limiter" and "Discharge" (drawing from battery even when plugged into a screen).

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