Leaving MacBook plugged in bad for battery?

I have an M1 MacBook Pro which I use 100% of the time in clamshell mode plugged into an external monitor. I have ‘Optimized battery charging’ turned on but I notice that the battery is always charged to 100%. My understanding is the system is supposed to let the battery drop to 80% every now and then (even when on power adapter) to maintain good battery health or is this not the case?

Is leaving my MacBook plugged in all the time bad for the battery health?

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I favor the Accidental Podcast folks view on this. Use your laptop how you’re gonna use it. There’s a limitation to battery technology, yes. Apple has done it’s best to avoid it with software adjustments.

But at the end of the day your battery is going to degrade no matter what you do. So use your laptop in the way that’s best for you.

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Thanks for the advice @dustinknopoff

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Same here. My M1 MBA is 8 months old and the battery is down to 90%. But I rarely ran out of battery on any of my Intel MacBooks so it’s not a problem for me.

My 2019 MBP has been plugged in most of the past three years – it rarely left the nest during Covid. The battery health is “normal”.

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Who knows? It is very hard to get any straight dope on the matter. My 2018 Intel MacBook Pro went back to Apple to replace its swelling battery after 35 months of powering a 24-inch Apple LG UltraFine monitor in clamshell mode.

That’s when I bought an M1 MacBook Air which I’m using without an external monitor and running it off the battery almost all the time. I make every effort to unplug it when it reaches 80% charge. I’ll be curious to see how well this battery lasts.

Leaving your MacBook fully charged will never result in it being automatically discharged, in my experience.

If you usually have it plugged in and then use it on battery and then recharge it, I believe it will more slowly charge it or not fully charge it at once.

I leave mine plugged in, but about once a week I try to use it on battery, just to give it a ‘workout’ but beyond that I don’t really worry about it.

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This makes a lot of sense. Great tip!

My MBP is plugged in 24x7 for 5 years (except when I am on the deck or just using it disconnected from power ) and never had any issues. I

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My 13" M1 MacBook Pro is constantly connected to power through a CalDigit dock. The “Optimize Battery Charging” setting is selected.

As described by @tjluoma above, I occasionally disconnect the MacBook from the power cable, allow the battery to discharge partially, then reconnect to power. After starting this practice, the battery would initially charge to an indicated 100% and remain there. After 3 weeks or so, I noticed that the battery would charge to 80% while displaying the message “On Hold: 80%” (see screenshot below), remain there for a few hours, then charge to 100% and remain there until disconnected from the power cable again.

CleanShot 2022-02-22 at 09.38.56

I have no way of knowing if this intermittent discharge-recharge to 80% for a short time-return to 100% charge is good or bad for the long-term battery life. I would prefer for a way to hold the battery charge at 80% (or even lower) while connected to the power cable until I manually toggle the battery charging process back on.

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You will probably be upgrading to a new MacBook way before your battery has issues. I have a new 14" MBP M1Max driving two Eizo 27" monitors in clamshell mode. I have had the unit for about 2 months now and it only left my desk to be used as a laptop for about an hour since I use my iPad for mobile computing. So, I’m not too concerned about battery life yet. That said, I do turn off the unit and the power strip when I’m done for the day. I have not used the unit over the weekend, so it stays powered off with no power connection then.
Cheers,
Bud

Take a look at AllDente it’s awesome.

Li-ion and polymer batteries (like the one in your MacBook) last the longest when operated between 20% and 60%. Keeping your battery at 100% most of the time will significantly shorten the lifespan of your MacBooks battery and Replacing an old battery is not only harmful to the environment but also costs up to $ 199. With AlDente installed, you can set a charging limit in a more healthy charging range, and with more features like Sailing Mode or Heat Protection you can keep your battery healthy even longer.

I have no connection with that app or development or whatsoerver but I’m just a happy user.

Also check out this thread.

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I didn’t think there was much I could do about it, but at the rate my MBA’s battery is losing capacity it will be below 80% before it’s two years old. So I tried AlDente for a couple of weeks then purchased a lifetime version of AlDente Pro. If it adds 5 months to the life of my battery it will have paid for itself.

TIL that AlDente Pro is in SetApp.

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How are you using it?

It does for me (with the optimize setting), but the results are very inconsistent on the MacBook that sometimes gets used on battery power. (I have two that are plugged in nearly 100% of the time and they sit at 80% pretty faithfully.)

I really, really, really wish Apple would have made the optimize setting just never charge past 80%, because their “learning how you use your computer” thing doesn’t work especially well.

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I contend that most of the power users here will be upgrading their MBPs every few years or at least way before the battery degrading issues become a real problem.
Regards,
Bud

You may be right. Computer enthusiasts tend to replace their hardware more often than regular users.

Currently I’m still just using it to cap charging to 80%. Occasionally running my MBA down to 30% or so was never enough to trigger its “Optimized Battery Charging”.

I have a powered spinning drive and 2 Samsung T7s connected to my Mac via a small Anker dock that will run the battery down at a rate of 10+ % an hour if I disconnect the dock from power. So now, at least once a week, I let my battery get some exercise while I’m out in the sunlight doing the same.

AlDente Pro has several other features that I may use later but I purchased it mainly to support the developer.

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We do tend to replace our computers regularly around here, but I think a lot of us are handing them down to someone who might ask us about a bad battery.

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