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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?

xxx374562
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3 Answers3

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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.

xxx374562
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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 Jul 01 '19 at 09:42
  • @Bataleon yes. it is as if there is no charging cable – xxx374562 Jul 06 '19 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 08 '19 at 08:39
  • @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 '19 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 05 '19 at 08:56
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    @Bloke There is some hard research here as well: https://accubattery.zendesk.com/hc/en-us/articles/210224725-Charging-research-and-methodology – dlsso Mar 04 '20 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

MacGuffin
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0

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).

mb21
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