Should I leave the MBA plugged in when it’s at my desk, regardless of battery level?

Continuing the discussion from M1 MBA and the progress toward the "holy grail" of workflows (ramble-y with questions at the end!):

Yes. The electronics and control software for battery maintenance knows a lot more about batteries than the majority of people who use them.

Apple’s advice: use your device. Plug it in when you can. If you store it, charge it to 50%. That’s it. That’s the tweet :slight_smile:

Something to remember is battery life is measured in charge/discharge cycles (and parts thereof), so if you use FruitJuice or some other misguided utility to run your battery down, and charge it back up, you’re just wasting cycles. People learned a lot of habits back in the NiCad days that just do not apply any more.


In regards to MBP plugged in all day, this is not the same situation, to my knowledge. But my 2014 MBP was plugged in 24/7 when I converted my workflow from portable to desktop style with an external monitor. It was plugged in for maybe 2-3 years in clamshell mode. When I was moving furniture, I had to disconnect everything, then noticed that the MBP battery was now bulging out pretty bad and rendered my keyboard and trackpad useless. Not sure if the batteries have been changed or updates since 2014, didn’t really follow up on that technology component.

Things have moved on thankfully.

I mentioned in the other post, but it’s worth bringing up here too: Lithium batteries don’t do well when constantly charged to 100% so Apple has addressed that by learning your usage patterns and not charging fully when you don’t need it. On any modern Mac running a reasonably modern version of the OS, it’s fine to leave it plugged in all the time :slight_smile:


Does Mojave consider modern? Maybe it is time for me upgrade one of the older Macs to Big Sur.

No mention of the (new?) optimized battery charging feature in MacOS?

Edit: I’ve not been able to tweak it but after a while I find that the battery stays charged to 80% constantly. For a full charge I disconnect it then reconnect and it understands I want a full charge. (At least I think that’s what happens)

My three year old 2018 15-inch MBP i7 went back to Apple for a battery beginning to bulge after being attached in clamshell mode to an LG UltraFine 4K monitor. I’m still not sure what to believe about Li-ion batteries.


See, that’s the weird thing. Every time I go to my computer, the battery is at 100%. It doesn’t look like Apple is ever letting off. The battery hasn’t been used since Wednesday, but it’s been at 100% that whole time.


At some point it decided charging to 100% was best given your usage patterns. Now that it’s at 100%, it isn’t going to discharge the battery. The wear and tear that Apple seeks to minimize occurs when charging above 80%. So it made the call, then charged to give you the best experience.


I’ve owned it for a week. And the first two days are the only battery usage I’ve ever had. Five full days of that time it’s been on the charger, because it’s been on my desk.

Can that possibly be “optimal”?

Edit: I think a balloon is a better analogy - most of the stretching happens when it’s almost full. But once “stretched”, there’s no need to deflate, as you’d just need to inflate/stretch again. Or you’d set off on a journey with a partially deflated balloon.

It’s like a water bottle connected to the tap. Once it’s full, it’s just hanging out waiting to be used. All the water is coming from the tap, the bottle is just sitting there with no wear and tear. When you disconnect, the water comes from the bottle.

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Hi guys,

Take a look at AllDente it’s awesome and solves all of your concerns.

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.

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I think the optimized/smart/whatever-Apple-branded-it charging was introduced in Catalina.

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TBH, I’m not sure why I should trust an independent developer (however talented and well-intentioned) over Apple when it comes to the best way of maintaining their batteries. It seems an unnecessary risk to take.


I can do a Option-Apple menu-System Information and then click Power to see more details about the battery condition, charge cycle.

I just changed the battery for my old 2013 MBA running on Mojave. The MagSafe is showing green i.e. it is fully charged. Going to the System Info, it shows that it is “Not charging”. I am betting that Mojave is also smart enough not to charge the battery once it is full.


It has to stop when it’s full, or you’ll end up with a fire :wink:

The optimized charging feature tries to understand your use patterns and will stop charging at around 80% until it anticipates that you’ll need more or you tell it to fully charge. Keeping a lithium battery fully charged for long periods is more chemically stressful than keeping it at around 50% to 80%

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Has anyone found a way to manually activate optimised charging? It only seems to kick in after a few days of me having it permanently on the charger (with the pref setting active).

I haven’t. It tries to learn your usage patterns so maybe that’s why it takes a few days?

I Don’t have a new MBP (yet) but I will add this to the discussion. My wife’s 2015 MBA is running (just recently), Catalina mostly Mojave. She has no concerns about optimizing battery life - she uses it when she needs it, plugs it in when she is lower on power. If I had to guess, I would say it has been mostly used 35% on battery, the rest of the time plugged in at her desk over the last 6 going on 7 years. It’s had 337 load cycles over 2450 days.

I just ran a Coconut Battery test and her battery is still at 83.2% capacity. So without giving it a second of thought, she has lost 2.8% of her battery life per year. To my way of thinking, that is more than acceptable and leads me to conclude I won’t worry about plugging in, leaving it plugged in or not. Just use it.

I had a G4 PowerBook (loved that laptop) and was very careful with battery maintenance. Had 2 battery bulges - both covered by Apple.


Exactly. The prospect that these two guys, or any app developers, know more than the fleet of engineers at Apple and their vendors would be a difficult case to argue.