Mohamed Kamal

macrumors member
Original poster
Jan 5, 2020
58
33
The theory is if you use it plugged in, it will use external power thus not exhausting battery’s charge cycles.
Is this true in real life? Will it otherwise harm the battery? Is it overall advisable?
 

AxelFoley

macrumors regular
Feb 16, 2015
102
69
You know what is true in my real life? I do not worry about the battery. I keep my MacBook Air plugged to external power whenever I can and use the internal power whenever I need to. Never worried about it and my oldest MacBook is 5 years old (MacBook Pro Mid-2015) and my newest MacBook Air is 6 months old. All is well and I am focused on enjoying my devices rather than use the devices with saving battery in mind.
Having talked about my real life, above, let's talk about yours. If your MacBook is charged externally 98% of time (for example) then it will not reduce your battery's theoretical life cycles and thus prolonging its lifespan. There is one other element that decreases battery capacity and that is time. As time elapses the battery will decrease in its performance regardless of whether it is used or not. There are other environmental elements as well such as ambient temperature etc.
My recommendation is, enjoy your MacBook.

Axel F.
 

Weaselboy

Moderator
Staff member
Jan 23, 2005
31,809
11,518
California
My recommendation is, enjoy your MacBook.
I'm with Axel here... just use your MacBook and enjoy it and don't sweat the battery.

Apple used to have some business on their web site about periodically exercising the battery, but a couple years ago they removed that recommendation and now talk more about charge cycles. So my thought it the exercise uses up charge cycles and is not really helpful.

I use my MBP in clamshell mode with it plugged in 24/7 for weeks on end, and never have had any battery issues.

Here is some battery info from Apple you can look over.


 

kohlson

macrumors 68020
Apr 23, 2010
2,423
729
In my experience keeping it plugged in all the time will shorten the battery life. While single-point experiences, my wife kept her 2012 MBA plugged in full time. Got the Replace Battery warning after 3 years and less than 250 cycles. When I asked the Apple tech about this, he told me something I already knew - keeping them plugged in full time shortens battery life. He also said batteries typically last from 3-6 years. My daughter had a 2011 MBA that she ran down every day and then fully charged (college student). Over 1000 cycles. About 4-1/2 years.
FWIW I have a MBP purchased in March 2014. The battery is still pretty good - 80+%. It is off power most of the time I use it, but usually between 50 and 90% charge.
 

Jim Lahey

macrumors 65816
Apr 8, 2014
1,108
1,817
Sunnyvale
Not worth worrying about. On the one hand, leaving it plugged into the mains all the time saves charge cycles. On the other hand it's good to keep the electrons moving, so running on battery at least intermittently might help to keep it healthy.

I'm in the "just enjoy it" camp. The battery can always be replaced if necessary. My 2017 15" MBP has been used almost exclusively on mains power for over two years, and Coconut Battery is reporting ~98% health and 14 charge cycles. From time-to-time I run it down to around 50% and then plug it back in for several more weeks.
 

flaubert

macrumors 6502
Jun 16, 2015
361
94
Portland, Oregon
There is an app called Fruit Juice that some people use to manage their battery charging:

 

Mohamed Kamal

macrumors member
Original poster
Jan 5, 2020
58
33
Thanks to everyone who replied! I fully intend to not compromise my experience by worrying about battery, but I intend to use my macbook on a desk anyway so i can easily keep it plugged or unplugged. That’s why i was wondering about which would be better for battery because i can do both.
 
  • Like
Reactions: chabig

26139

Suspended
Dec 27, 2003
4,315
376
Thanks to everyone who replied! I fully intend to not compromise my experience by worrying about battery, but I intend to use my macbook on a desk anyway so i can easily keep it plugged or unplugged. That’s why i was wondering about which would be better for battery because i can do both.

I also have my MBA plugged in a lot to a monitor and power.
I haven’t noticed any difference in battery health in doing so compared to the other six Mac laptops I’ve owned.
 

chrfr

macrumors G4
Jul 11, 2009
11,189
4,740
Thanks to everyone who replied! I fully intend to not compromise my experience by worrying about battery, but I intend to use my macbook on a desk anyway so i can easily keep it plugged or unplugged. That’s why i was wondering about which would be better for battery because i can do both.
Lithium-ion batteries such as those found in laptops do need to be periodically used. Leaving these batteries fully charged all the time is not good for their lifespans either. It's not uncommon for a battery that's several years old but only has a few charge cycles to need replacement. Batteries will age and lose capacity regardless of whether or not they're discharged, however.
 

sprague.rod

macrumors regular
Sep 29, 2017
101
47
This has been such a contentious issue for so long and there are credible arguments both ways. In the end I think I would agree with the first reply; it really doesn’t matter, just use and enjoy it and what will happen will happen. My MBP is plugged in most of the time, occasionally while travelling I may flatten the battery but I don’t go out of my way to do that regularly. No matter what you do to preserve it you may, like me, encounter an unpredictable situation where the battery swells and needs to be replaced when only 2 years old. This is the result of microscopic impurities and entirely random.
 

smirking

macrumors 68030
Aug 31, 2003
2,777
2,424
Silicon Valley
Never allowing your battery off the charger and always running it down all the time are both ways to shorten your battery's lifespan. Of course, lots of people do it anyway and get away with it and on the other side, some people rigidly follow guidelines like always keeping the charge between 20% and 80% but still somehow end up with premature battery death.

Having apps that rapidly drain the battery can also stress it out. Heat is bad for it. Long periods of inactivity is bad too.

Yeah, it's a pretty daunting list. So much of it is out of your control so you might as well just use your machine. I'm sure you didn't buy that laptop so you could spend all of your time obsessively monitoring the battery meter. Just try to avoid hitting 0% and don't leave it at 100% all of the time.

If you have AppleCare, they're replace the battery if it drops below 80% and an out of warranty battery replacement isn't prohibitively expensive for MacBook Airs anyway.

If you still want to geek out on battery management, head over to Battery University and go nuts.
 
Last edited:

smirking

macrumors 68030
Aug 31, 2003
2,777
2,424
Silicon Valley
No I’d rather just forget about the whole thing and use my laptop normally lol.

Hehe, that’s exactly the conclusion I came to.

I killed one battery by running it to 0% all the time so then with my (wrong) lesson learned I rarely ever let my next battery off of the charger. That died an early death too.

I figured I was doing something wrong so I started reading up on battery care. All the things you'd have to watch out for were just too much hassle for me so I simply decided to avoid either extreme and not worry too much.

MacBook Airs are very power efficient so you’ve got that going in your battery’s favor.
 
Last edited:

flygbuss

macrumors 6502a
Jul 22, 2018
668
1,202
Stockholm, Sweden
Still have a 2011 MBP and the GPU died several times. Now it runs a 2012 logic board with Nvidia instead of AMD GPU.
I also upgraded Memory and Storage over the years.
The battery on the other hand is still the original one the MBP came with.. No issues at all even though I never thought about special battery treatment and just used the it.

Edit: One thing maybe worth mentioning: I try not to exhaust the battery below 5 % but of course that happens also from time to time.
 
  • Like
Reactions: AxelFoley

LeeW

macrumors 68030
Feb 5, 2017
2,610
4,791
Glasgow, Scotland
I have used Apple laptops for close to a decade in clamshell mode about 80% of the time it is in use. Whenever I am at my desk at home or in the office it sits in a dock always plugged in. I never had a single issue with a shortened battery life that I am aware of.

My experience is that most people that have a view on it being bad never actually used it that way but just like to comment on why you should not do it.

Sure, someone will have an experience that they attribute to clamshell but really, how many times have you heard of a machine being damaged due to using it in clamshell? Exactly. A bit like running the CPU at 90c most of the time. How many cases of a failed CPU as a result? Indeed.

Use it the way it works best for you, not how others tell you how you should use it.
 
  • Like
Reactions: AxelFoley

MarkMissoula

macrumors member
Nov 15, 2008
92
1
I can attest to shortening your battery life. I bought my late 2017 air and mostly left it plugged in all the time instead of draining it periodically. Now with only a little over 200 cycles its pretty toast. Shuts down all the time randomly at different battery levels when not charging. Now I'm on the hunt for a good after-market battery.
 

LeeW

macrumors 68030
Feb 5, 2017
2,610
4,791
Glasgow, Scotland
mostly left it plugged in all the time

Ok, but

Now with only a little over 200 cycles

200 cycles do not sound like leaving it plugged in most of the time and not draining it periodically.

But that aside, you're attributing having it plugged in as the reason for the issues your machine has yet offered nothing to support what is at best an unproven theory.

It could simply be that that battery has turned or there is an issue with the device itself causing battery drain/spikes. Not uncommon and a new battery won't fix it.
 

chabig

macrumors G3
Sep 6, 2002
8,193
5,480
I can attest to shortening your battery life. I bought my late 2017 air and mostly left it plugged in all the time instead of draining it periodically. Now with only a little over 200 cycles its pretty toast. Shuts down all the time randomly at different battery levels when not charging. Now I'm on the hunt for a good after-market battery.
Your battery is under warranty. If it's truly toast, Apple will replace it for free.
 

LeeW

macrumors 68030
Feb 5, 2017
2,610
4,791
Glasgow, Scotland
Your battery is under warranty. If it's truly toast, Apple will replace it for free.

Not if it's faulty, that would only be covered under standard warranty. They will only replace out of device warranty if it's under 80% and less than 1,000 cycles.
 

MarkMissoula

macrumors member
Nov 15, 2008
92
1
Not if it's faulty, that would only be covered under standard warranty. They will only replace out of device warranty if it's under 80% and less than 1,000 cycles.
You're saying my battery is covered by apple if i meet that criteria?
 

Ghostrider72

macrumors member
May 24, 2020
44
11
The theory is if you use it plugged in, it will use external power thus not exhausting battery’s charge cycles.
Is this true in real life? Will it otherwise harm the battery? Is it overall advisable?
I would never do that, never. I have a six years old laptop and the batteries show no memory effect, no degradation or whatsoever. The secret? Working with batteries and recharge them only when they are at low level. In this case you are allowed to plug in and then continue working but as soon as they are full, disconnect the plug.
The reason? When the power charger is connected and the battery reaches its full charge, it keeps on pumping juice into the battery with the so called trickle charging. Why's that? That's because the underlying philosophy is to keep the laptop at full charge should the need to go without the grid, arise. And this is the problem, because this constant trickle causes the battery degradation. In my office we have tried over years the two different school of thought and the results were absolutely clear: work with battery and disconnect it whenever it reaches 90/100%.
Hope this helps.
Ps. My laptop stops me when battery reaches 7%. I believe it's better for you if this or the 5% threshold is never trespassed.
 

Arctic Moose

macrumors 6502
Jun 22, 2017
485
501
Gothenburg, Sweden
I'm with Axel here... just use your MacBook and enjoy it and don't sweat the battery.

Me too. I’ve done the same since my first laptop (PowerBook 5300) about 25 years ago, and my mid-2010 MacBook spent a lot of its life plugged in and is still fine.

Catalina now has battery health management, making worrying about it even less useful:

 
Last edited:
  • Like
Reactions: Weaselboy

teidon

macrumors 6502
Dec 22, 2009
441
205
There are at least three things that affects Li-Ion battery's lifetime: time, heat and charge level. Time will inevitably move forward, so there's nothing you can do about that. The higher the temperature of the battery is the faster it will degrade. Too low and too high charge level also causes degradation.

Heat is problematic in the sense that if you use the device, it will heat up and cause the battery to also heat up. You can reduce this by making sure there are no pointless applications using CPU or GPU. You might also want to lift the laptop off the table so that air can more easily circulate around it.

If you use the laptop plugged in all the time the battery's charge level will be around 100% all the time. It's impossible to say what is too low and too high, but if you want to be safe you might want to avoid less than 20% and no higher than 80%. Too high charge level with elevated temperature is double bad for the battery. There are applications that can limit the max charge to something lower, AlDente being one such app. It has a nice menubar item that allows you to easily change the max charge if you for example want to top the battery to 100%.
 

chabig

macrumors G3
Sep 6, 2002
8,193
5,480
Not if it's faulty, that would only be covered under standard warranty. They will only replace out of device warranty if it's under 80% and less than 1,000 cycles.
That would meet my definition of “toast”. So yeah, Apple will probably replace his battery for free.
 

LeeW

macrumors 68030
Feb 5, 2017
2,610
4,791
Glasgow, Scotland
That would meet my definition of “toast”. So yeah, Apple will probably replace his battery for free.

Well, as always, we don't actually know, need ask Apple first, there are plenty threads where they won't replace out of warranty and some where they did.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.