Why would you keep the MacBook always plugged in, whenever possible, for long periods?

[Alpha Centauri]

what I want to know is why does my MBP stop charging at 80%, unless I make it 'charge to full' via battery icon?

It's all explained here. Although my MBP is to 99% plugged in, I never had consistency for optimised charging to be effective on my MBP. As a matter of fact, my iP also had optimised charging only working for the first 6 months and then all became hit and miss with all required criteria met. You can probably tell I'm not a fan...only because of this contrariety.

 

[shadyman]

I have plugged it in 24/7 while using AlDente that keeps it at 80% constantly.

 

[whatnot]

because it's trying to save your battery capacity by default.

oh ok, I had no idea, but how does it work without the battery being fully charged, is 80% some kind of health benchmark? and doesn't it switch to battery power only when unplugged from the cord?

 

[whatnot]

It's all explained here. Although my MBP is to 99% plugged in, I never had consistency for optimised charging to be effective on my MBP. As a matter of fact, my iP also had optimised charging only working for the first 6 months and then all became hit and miss with all required criteria met. You can probably tell I'm not a fan...only because of this contrariety.

ok, coming from a mbp which wouldn't last one minute unplugged, this is this all very space age. from the link:

Optimized Battery Charging is designed to improve the lifespan of your battery and reduce the time your Mac spends fully charged.​

so having it fully charged while on power is bad? ok.

Your Mac learns your charging routine and aims to ensure that your Mac is fully charged when unplugged.​

I suppose I'll just leave it to its wisdom for now.

 

[A.F]

This is something i'm baffled about, i have the relevant setting activated myself and keep the MB consta-plugged in, but after a month from its purchase, the battery remains at 100%.
Needs to be mentioned i guess that:
i) i turn it off before tucking in and do not turn it back on until mid-late evening, no point for me to have it on while away; so maybe it hasn't accumulated the hours necessarily for this? Internet posts on the subject make me doubt that.
ii) in the off chance it has a part, that i did run the Onyx maintenance task 3 or 4 times. OS install, all my programs installed, after all my tweaks were done. Very mild settings on maintenance so sincerely doubting it affected this, but, mentioned.

Maybe in a couple of months this will sort itself out? No idea. Still at 100% as i edit this.

 

[Alpha Centauri]

ok, coming from a mbp which wouldn't last one minute unplugged, this is this all very space age. from the link:

Optimized Battery Charging is designed to improve the lifespan of your battery and reduce the time your Mac spends fully charged.​

so having it fully charged while on power is bad? ok.

Your Mac learns your charging routine and aims to ensure that your Mac is fully charged when unplugged.​

I suppose I'll just leave it to its wisdom for now.

That's right. Apple has optimised charging set to 80% as laid out in these support pages. An extract from it:

Optimized Battery Charging: "This feature helps to reduce the wear on your battery and improve its lifespan by learning your daily charging routine. It delays charging the battery past 80% when it predicts that you’ll be plugged in for an extended period of time, and aims to charge the battery before you unplug".

In the first six months of owning my 13 Mini optimised charging worked as advertised. It learned my location routines, usage patterns and capped charge overnight at 80%, fully charging a couple of hours prior to my alarm going off. After 6 months that feature stopped working entirely.

My M2 MBP's feature worked (sort of) but the algorithm had it easy with realistically only dealing with one location. If you recall, I mentioned the App AlDente? Don't mean to push it that much but it's been wonderful for my usage scenario. Afaik the limited base version is still free but the not overly costly Pro variant is just so much more customisable. What is interesting is that I actually got some percentages back on the battery health (just checked). Anecdotal, considering the inaccuracy of health measurement but "something" is doing its job.



PS Still got my 2009 MBP that survives 30min of not being tethered. It's had many many batteries in its lifespan.

 

[chmania]

"This feature helps to reduce the wear on your battery and improve its lifespan by learning your daily charging routine."

"Helps to reduce," doesn't really mean much, don't you think so?

 

[Alpha Centauri]

"Helps to reduce," doesn't really mean much, don't you think so?

It means everything actually. If you look across the board of use (EV's for example), the same rule applies also. The theoretical "green zone" for Li-ion batteries is to keep them at 80% (or below) when mainly tethered to power, and to not go below 20% to avoid a deep discharge state. So Apple's suggestion is correct. Now, if that's practical or indeed helps, the battery's chemical life will ultimately dictate that.

Also I understand obsessions with folks on MR constantly checking their battery's health status on MR but there's also nothing wrong with developing healthy charging routines IF these don't negatively impact intended use. We should be master of tools used and not the other way around. Certainly if tethered constantly or mainly, there's no sacrifice to keep thing's at 80%.

 

[chmania]

...there's no sacrifice to keep thing's at 80%.

Correct.
You can keep your MacBook charged up to 80%, and without it being always plugged in. You can always plug it in, when the battery level goes down to 20-30%, and that without the danger of some algorithm going haywire and, for example, heating up the battery.

 

[Alpha Centauri]

Correct.
You can keep your MacBook charged up to 80%, and without it being always plugged in. You can always plug it in, when the battery level goes down to 20-30%, and that without the danger of some algorithm going haywire and, for example, heating up the battery.

Or...you can let tools do this for you like Apple's solution, AlDente, etc instead of letting the device dictate the plugging/ unplugging.

 

[A.F]

If one takes away (and i do) the "Apple knows best" and the "newer technology=definitively better", one may begin with the basics

- Is the battery, as are all other batteries of this type, one with finite charge cycles?
Because if it is, keeping it plugged to the charger 24/7 is better, "algorithms" or not.

As to whether algorithms can further improve longivity, tbh, i cannot know.
- Temps (your area's, your home's)
- Humidity
- Use case

They all have a part to play and as such "algorithm" ""results"" are at best indicative.
At best because companies far, far less greedy than Apple cherry pick their results, on top of procuring them in very, but very controlled environments. Ours are not.

Lastly, most folks upgrade so often circa 2020+, the truth is we'll probably never really know.
(you'd need select individuals with multiple identical machines, in multiple real-life scenarios, over prolonged periods of time and so on)

I mean i'm here to ask about it, but.. let's keep it real
As to EVs, not the same. Generally speaking, it's the differential and the way the device copes with its alterations overtime. Moot comparison.

 

[chmania]

Or...you can let tools do this for you like Apple's solution, AlDente, etc instead of letting the device dictate the plugging/ unplugging.

Apple doesn't exactly state that they have a solution, do they? AlDente might have one. Anyway, the MacBook was designed for mobile use, but for stationary use, Apple has four desktop models, and they need to sell those too. Why would they want to assist in making a MacBook (Pro) a desktop machine? I suppose no one is trying to keep a MacBook Air constantly plugged in?

 

[Alpha Centauri]

Apple doesn't exactly state that they have a solution, do they? AlDente might have one. Anyway, the MacBook was designed for mobile use, but for stationary use, Apple has four desktop models, and they need to sell those too. Why would they want to assist in making a MacBook (Pro) a desktop machine? I suppose no one is trying to keep a MacBook Air constantly plugged in?

1. Apple's solution = optimised charging.
2. Designed for mobility..yes. Does it have flexibility of usage..also yes. Attach large displays if you want.
3. Why is optimised charging for all their mobile devices then?
4. Many folks don't want to be desk bound.

 

[Alpha Centauri]

As to EVs, not the same. Generally speaking, it's the differential and the way the device copes with its alterations overtime. Moot comparison.

Not moot at all mentioning EV's. First hit when gogling it.

The 80% rule: Why you shouldn't charge your EV to 100%

Did you know that your EV's battery is improved when kept below 100%? Read to learn more about the optimal charging percentage.

witricity.com

 

[mpetrides]

I keep my 16 inch M4 MBP plugged in virtually all the time and charge it to 100% because, on those rare occasions when I need to use it on battery, I want to be sure I have a fully charged battery.

My MBP is large enough and heavy enough that it's really more a "luggable" than a portable computer anyway. So I use its portability primarily to be able to relocate it within the house--out on the deck, on the couch in front of the fire, etc.. I rarely need to take it with me on trips or to a coffee shop and in the latter instance I usually bring my iPad Pro instead.

How do I deal with the issue of battery degradation? Why with "battery replacement insurance" (oops I mean AppleCare+ 🤣 ) of course. And, should the unexpected actually happen and I slip and drop the MBP, my AppleCare+ will cover that, too.

Peace of mind when I need to use it on battery (charging to 100% and keeping it there) and peace of mind with respect to battery life (with AppleCare+). Works for me. YMMV.

 

[chmania]

I did a little research on Aldente.

• AlDente’s core function is to limit charging to a user-defined percentage, which helps reduce battery wear over time.
• It doesn’t modify system files or firmware. It uses macOS’s built-in battery management APIs and kernel extensions to control charging.
• It only acts when the MacBook is plugged in - so there's no risk of it interfering with battery behaviour while on battery power.

Sleep, unplug, and replug with AlDente active

• AlDente's charge limit (80%) is enforced only while the MacBook is plugged in.
• If you put the MacBook Pro to sleep at 80%, unplug it, and leave it overnight, the battery may drop slightly (say to 78–79%) due to sleep drain.
• When you plug it back in, AlDente will resume charging only up to the set limit (80%) and then stop again. AlDente just allows charging until the set threshold is reached, then blocks further charging.

Shutdown overnight

• No battery drain (or negligible).
• Upon boot and plug-in, AlDente resumes its limit enforcement - charging only up to 80%

Why not leave it plugged in overnight?

• If the battery is already at 80%, AlDente blocks charging, but the MacBook remains connected to power, which means no battery wear, but also no benefit.
• Best practice for battery longevity would be to unplug overnight if you're not using the MacBook. Plug in only when needed, and let AlDente do its job keeping the battery at your set threshold.

I killed one MacBook Pro's battery while trying out Apple's Optimised Battery Charging Mode. The Apple software kept the battery level at around 80% most of the time, but its "health" deteriorated, and the cycle count increased rapidly when I used the MacBook Pro on battery a few times. I'll try the free version of Aldente for a few weeks to see how it goes, both at sleep and shutoff. I've never tried this Aldente software before.

So, while the MacBook Pro is "at work," it will be plugged in, and when it is not in use, it will either be in sleep mode or shut down.

 

[Alpha Centauri]

I'll try the free version of Aldente for a few weeks to see how it goes, both at sleep and shutoff. I've never tried this Aldente software before.

Cannot recall the differences between the free vs Pro version, possibly thermal protection, calibration mode and scheduling custom tasks, but the free download will give you a good idea on its functionality.

I've been using Pro (lifetime license) for 1 yr+ and have been very happy with the reliability, customisation (Pro) and the inevitable battery health and cycle count. The M2 is pretty much plugged in and sleeps and is only restarted when absolutely required i.e. software update.

Do post back on your experience after a couple of weeks.

 

[psingh01]

My currently laptop has been plugged in almost all of the time for the past 6 years. As was the one before that and the one before that… In 25 years of owning Mac laptops I’ve only ever had to replace batteries twice and both times was when the laptop was no longer my main machine. Meaning it was 4 or 5 years old backup.

 

[Apple_Robert]

I keep my MacBook Air plugged in all the time. I do use AlDente pro to help regulate the battery to keep it in proper health.

 

[A.F]

Not moot at all mentioning EV's. First hit when gogling it.

/pedantic-seeming, but sincerely not the intention!
Google's algorithms /= facts, rather they are an amalgamation of variables, such as (primarily) what result other people clicked on the most, what nets in the most profit for Google (not you), et al; but, aside that.

Use-case. Again.
If Macbooks had a setting that permanently disallowed charging above x% (as in actively, read further), if Macbooks had a software->hardware configuration that automatically adjusted for p-states, and if lastly said same config, for Macbooks, allowed for intelligent draining down to but no further than afore-mentioned x%, then i'd be a touch less cynical.

Until i see more (and today have had time to look this up quite exhaustively), i call.. semi-BS.
(which incidentally, albeit for different reasons, would -in a different forum- open up the "EV" subject yet again; a LOT of BS regarding "batteries" on that subject)

So as mentioned, i stick with physics
Finite charge cycles? Keep it plugged in as much as you can, even if you can afford regular replacements.
Now as to software?

Folks might want to have a look at this one, more than just AlDente out there; it's free of charge too:

GitHub - mhaeuser/Battery-Toolkit: Control the platform power state of your Apple Silicon Mac.

Control the platform power state of your Apple Silicon Mac. - mhaeuser/Battery-Toolkit

github.com

Still doesn't solve p-states, still requires the user to manually chase the battery.. but, these are on a level only Apple could go to. It being why i can come here and say BS.

 

[chmania]

Do post back on your experience after a couple of weeks.

Will do.

Why not leave it plugged in overnight?

• If the battery is already at 80%, AlDente blocks charging, but the MacBook remains connected to power, which means no battery wear, but also no benefit.
• Best practice for battery longevity would be to unplug overnight if you're not using the MacBook. Plug in only when needed, and let AlDente do its job keeping the battery at your set threshold.

I'm going to do it this way, put it to sleep or shutoff, and unplug it from electricity, and plug it in after I boot it up the next time.

 

[chmania]

I also found this info;

• AlDente and Optimised Battery Charging can technically coexist, but they may conflict in practice.
• AlDente sets a hard charge limit (e.g., 80%) and stops charging when that limit is reached.
• Optimised Battery Charging uses predictive algorithms to delay charging past 80% based on your habits, not a fixed cap.
• If both are enabled, macOS might try to charge past 80% when it thinks you need it, while AlDente will block it. This can lead to inconsistent behaviour or confusion about which system is controlling charging.

Best Practice: If you're using AlDente to manually manage your battery health, it's recommended to disable Optimised Battery Charging to avoid interference and ensure AlDente has full control.

Hope this helps.

 

[MacCheetah3]

what I want to know is why does my MBP stop charging at 80%, unless I make it 'charge to full' via battery icon?

because it's trying to save your battery capacity by default.

[...] is 80% some kind of health benchmark? [...]

Eighty-percent is a fair, sensible though also somewhat arbitrary compromise between having max battery capacity (i.e., mobile runtime) available and stressing the battery (cells)

Because of their chemical reaction nature err method, batteries become stressed at full charge and full discharge.* These stresses aren’t problematic unless the battery needs to cope with them for long periods, typically weeks, months, or even years.

This is also why:

It charges fast for convenience and slow for longevity.​

Your Apple lithium-ion battery uses fast charging to quickly reach 80% of its capacity, then switches to slower trickle charging. The amount of time it takes to reach that first 80% will vary depending on your settings and which device you’re charging. Software may limit charging above 80% when the recommended battery temperatures are exceeded. This combined process not only lets you get out and about sooner, it also extends the lifespan of your battery.

Batteries - Why Lithium-ion?

Learn why Apple rechargeable lithium-based technology provides the best performance for your iPhone, iPad, iPod, and MacBook.

www.apple.com

Ultimately, a battery cell is most comfortable at 50% (i.e., balanced chemical state).

Store it half-charged when you store it long term.​

If you want to store your device long term, two key factors will affect the overall health of your battery: the environmental temperature and the percentage of charge on the battery when it’s powered down for storage. Therefore, we recommend the following:

• Do not fully charge or fully discharge your device’s battery — charge it to around 50%. If you store a device when its battery is fully discharged, the battery could fall into a deep discharge state, which renders it incapable of holding a charge. Conversely, if you store it fully charged for an extended period of time, the battery may lose some capacity, leading to shorter battery life.
• Power down the device to avoid additional battery use.
• Place your device in a cool, moisture-free environment that’s less than 90° F (32° C).
• If you plan to store your device for longer than six months, charge it to 50% every six months.

Depending on how long you store your device, it may be in a low-battery state when you remove it from long-term storage. After it’s removed from storage, it may require 20 minutes of charging with the original adapter before you can use it.

Batteries - Why Lithium-ion?

Learn why Apple rechargeable lithium-based technology provides the best performance for your iPhone, iPad, iPod, and MacBook.

www.apple.com

By the way, some manufacturers may recommend above 50% (e.g., 60%) because there could be trickle discharge over time. Furthermore, that function may also be integrated, for example:

2. Do not store at 100%

To protect the battery cells, normally the batteries will start to discharge down to 50%-70% after the 5 days. If a battery will not be used for 5 days or longer, discharge it to 50%-70% state of charge for storage. If a battery is below 40-50% it should be charged until it reaches this range for storage.

Maintaining and Storing Your ATOM Series Drone Batteries

Most of Potensic drones are powered by intelligent batteries, so what is “intelligent batteries”? Let's take a closer look into Potensic’s intelligent batteries, and this guide walks you through some details, including a brief introduction of the intellige

www.potensic.com

* Even when your Apple device automatically powers off due to (‘critically') low battery power/charge, there’s still a significant amount of charge — I presume ~10% — remaining. This is to allow displaying the low battery icon (when you attempt to power on the device in said state), Find My tracking to be available for briefly longer, and help prevent deep discharge. And when an Apple device reaches 100%, it will stop charging and run off battery until the battery state-of-charge drops several percent, then recharges to 100%, and repeats. This overcharging cycle is not typically shown to users (i.e., the battery charge percentage won’t move below 100% while “fully charged"). You can observe in apps such as coconutBattery though.

 

[chmania]

I shied away from AlDente in the past, thinking that Apple's Optimised Charging Mode would help maintain the battery health at its best, but unfortunately, it didn't. Here's something more I discovered regarding this matter with AlDente (or a command line script) that can stop the battery charging at 80% and redirect the power from the charger to run the MacBook.

How long can you “sit” at 80%?

• Weeks or months at ~80% is perfectly safe.
• Modern lithium-ion packs don’t need “exercise” to stay healthy like old nickel-cadmium ones did.
• The main stress factors are time at very high voltage (≈100%), excessive heat, and many charge cycles.

So if your MBP spends most of its life plugged in, capped at ~80%, that’s actually the ideal storage/usage condition for longevity.

Do you ever need to go to 100% or run it down?

• No requirement for health. Apple batteries don’t need “conditioning.”
• Some people do a full cycle (20–100%) every month or two to help macOS/SMC recalibrate the battery meter -- but this is for accuracy of reporting, not battery chemistry.
• If you never go above 80%, you might notice the macOS percentage indicator becoming slightly less precise over time. Running a full cycle occasionally can fix that.

Practical advice...

• Keep it at 60–80% if you’re mostly desk-bound.
• Charge to 100% only when you know you’ll be unplugged for travel or long work sessions.
• Maybe let it run a full cycle (say 20% → 100% → back to 20%) every couple of months to keep the battery gauge calibrated.
• It's always best to power off your MacBook every now and then to perform that SMC reboot.
  
  I have disabled the Optimised Battery Charging Mode, while using Aldente. The MBP would be shutdown for the night and off the charger.

 

[m1maverick]

80% seems to be the agreed upon limit to charge a battery unless the full capacity is needed. Tesla recommends owners (those without LFP batteries) limit charging to 80% for day-to-day driving. A lot of EV charging times are given up to 80% of capacity.