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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?

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

  • So if the Macbook is at 50% (for example) when you plug in the HDMI cable, does it stay at 50%? – Bataleon Jul 1 at 9:42
  • @Bataleon yes. it is as if there is no charging cable – xxx374562 Jul 6 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 Jul 8 at 8:39
  • @Bataleon How significant are the effects of keeping it on the charger almost all the time? I've heard various things about what Li-ion batteries don't like... Do you have a source to support this with some data? How exactly do you use your laptop when at work for example? – Bloke Jul 31 at 16:20
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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 Aug 5 at 8:56

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