Laptop Battery Lifetime Revisited

[TromboneAl]

Here's how I've been using my new Macbook Air:

During the week, it sits unused. Every Saturday, we go into town, and I use it for an hour or two at a coffee shop. Sometimes we go on a several-day trip out of town, and I use it then.

I've seen some say that with the latest batteries and technology, it's okay to just leave the laptop plugged in. Also, Apple says that it's the number of discharge/recharge cycles that's important.

OTOH, Apple says that if you're going to not use your machine for months, you should leave it charged to about 50%.

I will probably use this laptop long after newer versions have come out, and I can't just buy a new battery on Amazon and put it in myself. So: Lifespan is important.

If the laptop is on sleep, waking it up just takes a touch of my finger on the fingerprint reader. If I shut it down, it takes much longer. But if it's only on sleep, it discharges by 10-20% per day.

I'm considering this system:

1. I calculate how much it discharges in 24 hours when sleeping. Let's say it's 15%.
2. I calculate how long it takes to recharge it by 15% (Let's say two hours).
3. I let the charge drop to, say 60%.
4. I plug it in, but on a timer that's set so that every night it recharges for two hours.

Result: It's always available with a touch of my finger, but it stays in the middle ranges of charge.

But maybe that's worse that just leaving it plugged in.

 

[ERD50]

Just like I told you on the first go-around of this, you are trading one thing for another. Yes, best to not leave it at full charge, but if you do that by discharging it, you are trading for increased charge cycles, which also degrades the battery.

Which is worse? I dunno.

But that is not the same as some of the 'smart' algorithms in firmware that charge to say, 80%, and stop charging, but keep powering the device from the line. That's not adding charge cycles. That's what you really want. Maybe Apple offers this? I'd check that out. After all, they keep claiming the tight integration of HW/SW gives them these advantages.

If you typically only use it once a week, I'd let the last charge cycle go to 50-80% and turn it off. What's an extra boot cycle once a week?

-ERD50

 

[Sunset]

J...

If you typically only use it once a week, I'd let the last charge cycle go to 50-80% and turn it off. What's an extra boot cycle once a week?

-ERD50

+1
Exactly the right way to do it.
This way it will not need recharging until 3 or 4 weeks are up. About 6-8 hrs usage.
This is nearly once per month (there are 4.3 wks per month on avg) so that's 13 charges a year !

 

[mpeirce]

Check your "Power Nap" setting. https://support.apple.com/en-us/HT204032

And more info from Apple on "Maximizing Battery Life and Lifespan": https://www.apple.com/batteries/maximizing-performance/

 

[TromboneAl]

Check your "Power Nap" setting. https://support.apple.com/en-us/HT204032

And more info from Apple on "Maximizing Battery Life and Lifespan": https://www.apple.com/batteries/maximizing-performance/

You're right. I think I overestimated the discharge when sleeping. Powernap is off now, but maybe it was on before. I'm retesting now.

 

[ERD50]

I was curious, did some poking around. You def want Power Nap off. Hope that fixes it for you.

But I came across this thread:

https://forums.macrumors.com/threads/why-do-macbook-pros-drain-battery-while-sleeping.2111961/page-6

Geez, lotsa people having issues ( 10-20% loss overnight in sleep mode) and it seems hard to pin down. Some resorted to 'hibernate' (essentially a power /off/on, but memory/settings are stored to the hard drive and reloaded on power up.

Lotsa blaming recent versions of the OS. Lotsa digging into the terminal. Man, I'm on Linux and can't recall the last time I had to go to the terminal to troubleshoot anything.

But worse case, if you really go days w/o use, just power down.

-ERD50

 

[folivier]

How many seconds does it take to boot up from off?
IOW how impatient are you?

 

[Lakedog]

Leave my MacBook Air plugged in most of the time unless on the road and have since new (2012 model). Still on the original battery which has just recently been showing markedly decreased performance (only get 3 hours or so on full charge).

You can buy replacement batteries online (Amazon) and replace yourself so I will likely do that soon. Apple says they cannot (or will not) replace the battery due to age of my Air.

 

[TromboneAl]

Without Powernap:

1/6/19 1:25:01 PM 51%

1/6/19 2:26:08 PM 51%

1/6/19 3:36:02 PM 51%

1/7/19 6:24:13 AM 48%

 

[TromboneAl]

How many seconds does it take to boot up from off?
IOW how impatient are you?

I'm pretty impatient when it comes to computers.

Recover from sleep:

Push Touch ID button
Instant on (all windows open)

Total time: Less that a second​

Recover from shutdown:

Push Touch ID button
Wait for User selection screen
Select User
Enter long password (without being able to see it)
Password wrong
Enter long password again
Wait about 40 seconds for bootup
Computer on

Total time: 1 minute 9 seconds (would require extra time to open all windows)​

 

[folivier]

I get it. I've never been accused of being patient, especially by my DW.
On my Macs there is an option when shutting down to reopen all windows when starting up. But on my MacBook I hardly ever shut it down.

"Total time: 1 minute 9 seconds (would require extra time to open all windows)"

 

[FUEGO]

40 seconds to boot? Do you have an SSD or a regular spinning hard drive? I usually put my Win10 computer to sleep so I get the instant wake up. But I just tested hibernate (it saves the current OS state to the SSD) and it only takes 8-10 seconds to boot. And this is on a cheapo mid-range notebook that cost $350 2 years ago.

 

[Chuckanut]

Note that the Power-Nap feature needs to be set for battery power and adapter power. You can sent it differently for the battery so as to preserve more battery energy. My battery power-nap is off. But, when plugged in, it's own. Works for me.

 

[ERD50]

Without Powernap:

1/6/19 1:25:01 PM 51%

1/6/19 2:26:08 PM 51%

1/6/19 3:36:02 PM 51%

1/7/19 6:24:13 AM 48%

And how exactly does this compare before/after?

I think you were saying you lost 15% in 24 hours? But was that an estimate? Now maybe 4% with Power Nap turned off?

I'm not sure about those numbers - I think you need to capture some data over several days, with and w/o Power Nap.

-ERD50

 

[Jerry1]

This is something I don't quite understand. I use the machine how I want. If the battery dies a bit early because of that, so be it. If you think you will get the computer to live past the life of the battery and the time that the manufacture supports new batteries, then I would set a reminder to keep tabs on the manufacture and when they announce that they are going to discontinue the support, buy a new battery. If you're doing this because it's in your nature, that I can relate to, however, for this scenario, it's not in my nature. I don't abuse my equipment, but I use it how I desire and I've never had equipment last shorter than how long I wanted to keep it. I just gave my MacBook Air to my daughter after several years and it's working fine, battery and all. I think I bought it in 2012 (it was before the backlit keyboard) and I gave it away because I just wasn't using it since I got my iPad (and she needed a computer).

Just use it and enjoy it.

 

[ERD50]

This is something I don't quite understand. I use the machine how I want. If the battery dies a bit early because of that, so be it. ...
Just use it and enjoy it. .

OK, so let me explain it to you from some one who does understand.

Sure, use it how you see fit, enjoy it, all that's fine. But if there is something you can do to extend its life, and that 'something' doesn't take much time/effort, why wouldn't you do that?

It makes perfect sense to me. It keeps something (the battery or the entire computer) out of a landfill for a longer time. Don't you care about those things?

It's worth researching, isn't it? Now, if it turns out it took extraordinary and inconvenient effort to extend the life just a little bit, sure, you can decide that's not worth it. But if you don't research it, you don't know that. I'm a big fan of informed decisions.

-ERD50

 

[TromboneAl]

Thanks for the info, ERD50. Looks like that problem is what I'm dealing with.

I've made an end-run around the issue by setting things up so that after five minutes, the laptop hibernates instead of sleeps. That is, it saves the info to disk then shuts down. Because it has a solid-state disk, we're only talking about a few extra seconds here. Also, I can use my fingerprint instead of a long password to confirm my identity.

BTW, in my research for my legal thriller, I learned that police that force you to use your fingerprint to unlock a device but can't force you to give them your password. It's a fifth-amendment issue. Same for keys vs combinations.

 

[TromboneAl]

And how exactly does this compare before/after?

I think you were saying you lost 15% in 24 hours? But was that an estimate? Now maybe 4% with Power Nap turned off?

I'm not sure about those numbers - I think you need to capture some data over several days, with and w/o Power Nap.

-ERD50

Yes, IIRC, I just slept the laptop at 100% and the next day it was at 80%. Said, "Huh." I don't remember whether I had powernap on or not.

Yes, I could experiment and get a definitive answer, but at this point, I have a solution that works, and I don't need powernap.

 

[ERD50]

...

I've made an end-run around the issue by setting things up so that after five minutes, the laptop hibernates instead of sleeps. That is, it saves the info to disk then shuts down. Because it has a solid-state disk, we're only talking about a few extra seconds here. Also, I can use my fingerprint instead of a long password to confirm my identity.

...

I'm a little confused. How is this different from turning it off, which you said you don't want to do?

As I understand it, and I'm pretty sure this is the same in the Apple world ( they call it "Safe Sleep"?, "hibernate" is shutting it 'off'. The difference from a 'normal ' shutdown is it writes current RAM to your hard drive/SSD before it shuts down. So on start up, it reloads this so you are right back where you left off (documents and windows recovered). This will likely take just a little longer than a regular off/on cycle.

It makes sense to do it that way, there just seems to be a disconnect between this and you saying you didn't want to wait for it to boot up, Did you change your mind on that?

I think I read there may be a delay before it actually hibernates (edit - OK, you mentioned after 5 minutes....) - maybe you are actually seeing a fast start up because it is really just in regular sleep mode, it has not hibernated yet?

-ERD50

 

[Jerry1]

OK, so let me explain it to you from some one who does understand.

Sure, use it how you see fit, enjoy it, all that's fine. But if there is something you can do to extend its life, and that 'something' doesn't take much time/effort, why wouldn't you do that?

It makes perfect sense to me. It keeps something (the battery or the entire computer) out of a landfill for a longer time. Don't you care about those things?

It's worth researching, isn't it? Now, if it turns out it took extraordinary and inconvenient effort to extend the life just a little bit, sure, you can decide that's not worth it. But if you don't research it, you don't know that. I'm a big fan of informed decisions.

-ERD50

Either I’m just lucky or my natural habits are in sync with the battery, but I’ve never had a battery problem and frankly, never gave it much thought. I think my first iPhone lasted over 4 years before work made me turn it in. My next one lasted another 4 years before I retired and my laptop is still working. They just don’t seem as fragile to me as is described. My laptop was mostly plugged in, but the battery is still working fine. My phones, I plug in at night and I’ve never had them not last through the day unless I was on a bunch of conference calls. I guess luck is fickle and ignorance is bliss. Seems to be working, so I won’t mess with it.

And yes, I do care about keeping things out of a landfill. Until they improved the batteries on hand tools (cordless drills), it was very disturbing that, one, the battery would go bad very quickly, but two, and most disturbing, is that the battery cost as much as replacing the tool, which gave you a new battery and a new tool and charger. Thus making the old tool worthless as no one would buy a battery for $75 when on sale you could get a new tool for say $90. That was frustrating.

 

[TromboneAl]

Just like I told you on the first go-around of this, you are trading one thing for another.

-ERD50

You had me worried that I'd recently brought this up and forgotten, but it's been a while, right?

The situation with my old laptop was different in that I used it every day.

 

[TromboneAl]

I'm a little confused. How is this different from turning it off, which you said you don't want to do?

As I understand it, and I'm pretty sure this is the same in the Apple world ( they call it "Safe Sleep"?, "hibernate" is shutting it 'off'. The difference from a 'normal ' shutdown is it writes current RAM to your hard drive/SSD before it shuts down. So on start up, it reloads this so you are right back where you left off (documents and windows recovered). This will likely take just a little longer than a regular off/on cycle.

It makes sense to do it that way, there just seems to be a disconnect between this and you saying you didn't want to wait for it to boot up, Did you change your mind on that?

I think I read there may be a delay before it actually hibernates (edit - OK, you mentioned after 5 minutes....) - maybe you are actually seeing a fast start up because it is really just in regular sleep mode, it has not hibernated yet?

-ERD50

Hibernate is quite different than shutting down. It's faster to just restore the memory than go through all the booting up stuff. The sleepimage file is only 1 gig in size:

I set it to hibernate immediately and got the fast startup. Also, I tried setting the delay to only one minute, waited, and got the fast startup. That tells me that a restart from hibernate is much faster than booting up.

There's no way to know if the machine is totally off, and no way to detect disk access, so I only have strong but circumstantial evidence that it has hibernated.

I should probably just set it to hibernate immediately.

 

[TromboneAl]

Just tested. From the moment I open the case to windows open:

When sleeping: 2 seconds
When hibernating: 9 seconds

 

[ERD50]

Hibernate is quite different than shutting down. It's faster to just restore the memory than go through all the booting up stuff. The sleepimage file is only 1 gig in size:


I set it to hibernate immediately and got the fast startup. Also, I tried setting the delay to only one minute, waited, and got the fast startup. That tells me that a restart from hibernate is much faster than booting up.

There's no way to know if the machine is totally off, and no way to detect disk access, so I only have strong but circumstantial evidence that it has hibernated.

I should probably just set it to hibernate immediately.

OK, thanks, you are right. This has either changed from the last time I studied it, or my memory is corrupt, or both.

I was thinking that hibernate did a bare boot, and then loaded this stuff from memory, but I just read that the entire image is loaded from that one file, and that provided the machine with everything it needs, it essentially already is booted. Reading from one file is faster than reading from many files,plus you skip a lot of the processing of each file.

I also just read that they compress that file, which is interesting. In the old days, you compressed to save disk space, but took a hit in performance since the decompress algorithm had to run. Now, CPU is faster than the disk, and disks are big, so compress/decompress saves time!

Bottom line - it looks like hibernate is a good option for you! Success!

-ERD50

 

[ERD50]

Either I’m just lucky or my natural habits are in sync with the battery, but I’ve never had a battery problem and frankly, never gave it much thought. I think my first iPhone lasted over 4 years before work made me turn it in. My next one lasted another 4 years before I retired and my laptop is still working. They just don’t seem as fragile to me as is described. My laptop was mostly plugged in, but the battery is still working fine. My phones, I plug in at night and I’ve never had them not last through the day unless I was on a bunch of conference calls. I guess luck is fickle and ignorance is bliss. Seems to be working, so I won’t mess with it.

And yes, I do care about keeping things out of a landfill. Until they improved the batteries on hand tools (cordless drills), it was very disturbing that, one, the battery would go bad very quickly, but two, and most disturbing, is that the battery cost as much as replacing the tool, which gave you a new battery and a new tool and charger. Thus making the old tool worthless as no one would buy a battery for $75 when on sale you could get a new tool for say $90. That was frustrating.

The tool analogy somewhat applies to these Apple laptops and most phones now. That does make battery preservation a bigger deal.

I also have not noticed big degradation with my laptops, which I use as desktops - they are plugged in almost all the time. But I also have not tested the battery fully in a while, since I so rarely us them off power, but as I recall, they were OK after 4+ years. But I could also buy a snap-in replacement battery for my laptops, so I'm not too concerned either.

It's hard to say how bad it is to keep it 100% charged. It's better not to, but how much is hard to say.

I might take my tool batteries in to have the cells replaced, I've heard that is cheaper? Supposedly, some local places will do it, you need a spot welder to get those cells together. Hmmm, maybe buy a cheap spot welder from Harbor Freight? But the tool is > 10 years old, I have two batteries, so I just swap them. Probably time for a new tool anyhow.

-ERD50