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Ask HN: Should I unplug my laptop charger at 100%?

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Re: Ask HN: Should I unplug my laptop charger at 100%?

#161

Post by r00fus »

tjohns wrote: post #68
hvjackson wrote: post #63

Earlier quoted context omitted.

The fact that Apple no longer has this statements on their website makes me think it's no longer true for their batteries (if it ever was).

They do have some advice on "long-term" storage here, which is roughly along those lines: https://www.apple.com/batteries/maximizing-performance/ They don't say what "long-term" is, but monthly seems reasonable to me.

It specifically calls out recharging it to 50% every six months, so I assume it's a month+ kind of long term.

Also Apple seems to indicate that storage in a deep discharge state is far more damaging than storage at near-capacity based on the wording.

So if you're in doubt, charge it before you store it.

Finally, I don't think there's anything on that page that says you shouldn't keep your laptop plugged in when it's at 100%. I would be very surprised if they didn't have some cycle-conditioning going on. I have both a 2008 unibody and 2010 MBP, both essentially remaining plugged in for years. I don't think the battery life is abnormally low for their age, they still are capable of several hours of usage on battery.

Re: Ask HN: Should I unplug my laptop charger at 100%?

#162

Post by izolate »

hvjackson wrote: post #63
paulannesley wrote: post #18

> For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for…

The fact that Apple no longer has this statements on their website makes me think it's no longer true for their batteries (if it ever was).

Or they're trying to bolster sales of their warranty initative: Apple Care

Re: Ask HN: Should I unplug my laptop charger at 100%?

#163

Post by lh7777 »

JoshGlazebrook wrote: post #125
DavideNL wrote: post #107

Earlier quoted context omitted.

That's nice to know. However, i'd rather buy a new battery after 5 years (if my laptop is still fit and the battery is dead), than having to complicate my life and think about when to unplug or charge my laptop multiple times each day for 5 years... My Macbook air from mid 2011 is currently at 100/6700*5629 = 84% battery health. (6700 = design capacity, gathered from "ioreg -l -n AppleSmartBattery -r".

Is your machine even operational? My macbook air from 2011 (with Yosemite) is sluggish to the point of being unbearable to use and just collects dust.

My 2011 11" Air (i7) runs 10.10 just fine. I haven't noticed any slowdown over the past 4 years, although I do disable all the unnecessary transparency and animations Apple keeps adding for seemingly no reason.

By the way, my battery health is also around 85% after 500 cycles and being plugged in and charged to 100% whenever possible.

Re: Ask HN: Should I unplug my laptop charger at 100%?

#164

Post by misnome »

gpvos wrote: post #115
bkanber wrote: post #58

Source: I have a master's degree in mechanical engineering in hybrid vehicle powertrains, and a big part of my research was battery technology. I spent some time working with the folks at National Semiconductor learning this, so I have several primary sources. Disclaimer: my knowledge of the field is from ca 2010. 1) Lots of deep discharge cycles do negatively affect battery life. Try not to jump between 0% and 100%…

So what my laptop should do automatically is to stop charging once it hits ~90%, and start charging again when it hits ~40%. And the OS should give me an easy-to-reach option to "charge to 100%" for when I'm about to make a trip. Why hasn't anyone implemented this yet?

Macbooks have also done this for, like, forever, but more with the top few percent than 10%-60%

Re: Ask HN: Should I unplug my laptop charger at 100%?

#165

Post by hsitz »

rexf wrote: post #120
DavideNL wrote: post #107

Earlier quoted context omitted.

That's nice to know. However, i'd rather buy a new battery after 5 years (if my laptop is still fit and the battery is dead), than having to complicate my life and think about when to unplug or charge my laptop multiple times each day for 5 years... My Macbook air from mid 2011 is currently at 100/6700*5629 = 84% battery health. (6700 = design capacity, gathered from "ioreg -l -n AppleSmartBattery -r".

I agree with you. Instead of optimizing for battery life by constantly checking & adjusting my charging, I'd rather live my life focusing on other things. What I do is super simple: plug it in whenever possible.

Same here. I have no reason to dispute the expert who says Lithium-ion batteries "don't love 100%". Fine, but they don't seem to dislike it too much, either. So far I haven't had any batteries that didn't perform well when they were mostly plugged in, occasionally discharged in mobile use.

I see some similarities to, e.g., medical pronouncements that some particular food increases risk of cancer. It's easy to get alarmed, but there's a big difference between it increasing my likelihood of getting cancer by 0.05% and making cancer, say, (just to illustrate the point) 100 times more likely. The former I would likely ignore and the latter would probably make me give up the food instantly.

Re: Ask HN: Should I unplug my laptop charger at 100%?

#166

Post by arrrg »

adrusi wrote: post #106
brador wrote: post #47

Consider the cost of a replacement battery and if it's worth the subconcious mental strain this consideration places on you. In short, leave it in because it's not worth worrying about.

Assuming your computer has a replaceable battery, which is not the case always. Replacing a $80 battery is worth it to avoid stress, but replacing a $2000 ultrabook may not be.

Apple charges something like $120 for changing the battery out. Not worth the stress to micromanage that, really not. It’s never about $2000.

Re: Ask HN: Should I unplug my laptop charger at 100%?

#167

Post by johnymontana »

DavideNL wrote: post #107
bkanber wrote: post #58

Source: I have a master's degree in mechanical engineering in hybrid vehicle powertrains, and a big part of my research was battery technology. I spent some time working with the folks at National Semiconductor learning this, so I have several primary sources. Disclaimer: my knowledge of the field is from ca 2010. 1) Lots of deep discharge cycles do negatively affect battery life. Try not to jump between 0% and 100%…

That's nice to know. However, i'd rather buy a new battery after 5 years (if my laptop is still fit and the battery is dead), than having to complicate my life and think about when to unplug or charge my laptop multiple times each day for 5 years... My Macbook air from mid 2011 is currently at 100/6700*5629 = 84% battery health. (6700 = design capacity, gathered from "ioreg -l -n AppleSmartBattery -r".

Could you clarify how you arrived at 84% battery health? After the command "ioreg -l -n AppleSmartBattery -r" I see DesignCapacity, but where does the other number (5629) come from? I'd like to compute battery health myself...

Re: Ask HN: Should I unplug my laptop charger at 100%?

#168

Post by mc32 »

bkanber wrote: post #58

Source: I have a master's degree in mechanical engineering in hybrid vehicle powertrains, and a big part of my research was battery technology. I spent some time working with the folks at National Semiconductor learning this, so I have several primary sources. Disclaimer: my knowledge of the field is from ca 2010. 1) Lots of deep discharge cycles do negatively affect battery life. Try not to jump between 0% and 100%…

It'd be nice if the battery controller/charger had the intelligence to make these optimizations transparent to the end user. So present them with 100% or whatever, but in actuality, the battery is at 90%, most of the time it's plugged in, and so on.

Re: Ask HN: Should I unplug my laptop charger at 100%?

#169

Post by 0942v8653 »

JoshGlazebrook wrote: post #125
DavideNL wrote: post #107

Earlier quoted context omitted.

That's nice to know. However, i'd rather buy a new battery after 5 years (if my laptop is still fit and the battery is dead), than having to complicate my life and think about when to unplug or charge my laptop multiple times each day for 5 years... My Macbook air from mid 2011 is currently at 100/6700*5629 = 84% battery health. (6700 = design capacity, gathered from "ioreg -l -n AppleSmartBattery -r".

Is your machine even operational? My macbook air from 2011 (with Yosemite) is sluggish to the point of being unbearable to use and just collects dust.

Yosemite is a total mess, but it has gotten slightly better with 10.10.3 (if you are willing to ignore the Photos app, which launches constantly for no reason).

If you are willing to mess with drivers, you may want to try installing Linux. On a 2013 Air, battery life and performance (even graphics!) are surprisingly better with Debian Jessie than with OS X. Of course, it is a newer model than yours, but the drivers will only be more stable and mature with a 2011. Especially if you have 4 GB RAM and you're running into a memory barrier with OS X, you should see a significant improvement.

Re: Ask HN: Should I unplug my laptop charger at 100%?

#170

Post by bluedino »

johnymontana wrote: post #167
DavideNL wrote: post #107

Earlier quoted context omitted.

That's nice to know. However, i'd rather buy a new battery after 5 years (if my laptop is still fit and the battery is dead), than having to complicate my life and think about when to unplug or charge my laptop multiple times each day for 5 years... My Macbook air from mid 2011 is currently at 100/6700*5629 = 84% battery health. (6700 = design capacity, gathered from "ioreg -l -n AppleSmartBattery -r".

Could you clarify how you arrived at 84% battery health? After the command "ioreg -l -n AppleSmartBattery -r" I see DesignCapacity, but where does the other number (5629) come from? I'd like to compute battery health myself...

He's just dividing the current battery capacity by the 'new' battery capacity. You can just let a program like Coconut Battery do it for you.
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