Huge mistake here - he says he cycles his battery! DO NOT DO THIS TO LITHIUM ION BATTERIES! Lithium Ion will last longer by NOT allowing the cells to be fully discharged!
This is the opposite of Nickel Metal Hydride and Nickel Cadmium - these types of batteries DO require a full discharge and full recharge in order to provide a longer life.
In addition, the number of discharges, the temperature, etc all come into play with lithium ion. These thinner laptops are actually lithium ion polymer, where the materials are folded into packs...much more susceptible to the elements, like heat.
Edit: Just want to point out that charging a laptop while using it could potentially create more heat, degrading the battery. I'm not sure what is more damaging - letting the li-ion battery drop below 70%, or charge it while the laptop is being used. So many variables!
The really dumb thing is that, as far as I can tell, a battery's controller generally counts a "cycle" as "started discharging, started charging", regardless of time in between. At least, that's how it was with my MacBook a few years ago. Unplug, plug in, cycle count increases.
The crappy thing about that is warranties. Apple, for example (at least last I checked; I don't use a Mac anymore) , would replace a battery if it had under some number of charge cycles (and presumably was less than a year old), but not if it had more than that number.
That means that if you treat your battery really nicely by always keeping its charge between 40% and 60%, and it turns out to be defective, they probably won't replace it because of how many "cycles" it has gone through.
Of course, those kinds of cycles have very little to do with the longevity of a Li+ or LiPo battery anyway. A better metric would be total energy output over time, which would be far simpler to calculate anyway.
As they say in the renewable energy field: the majority of batteries do not die peacefully, they are murdered.
As a bit of a re-assurance, the typical laptop power circuit in a laptop using lipo is aware of this and will simply refuse to drop the battery below a certain level so likely the damage is somewhat limited. Still, if you don't need to discharge a battery all the way as far as the circuitry will let you with lipo's you'd better not.
Fully discharging any battery isn't good for it. NiCd had the particular problem of "memory" developing though, so going through a full discharge cycle was necessary to prevent the memory forming. It wasn't good for the battery, but it was better than letting the memory develop.
I'm not aware of NiMH developing a memory, so that wouldn't be a good thing to do with NiMH either. I always tried to avoid full discharge of my NiMH batteries and always got a pretty long life out of them.
Really the full discharge cycle is an artifact of the needs of one particular chemistry (NiCd) that became something that "everybody knows" you should do long after it became counterproductive.
I believe you are correct on the "cycling the battery", which I believe you want to avoid, so that you battery will be able to charge fully for longer.
"A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could listen to your iPod for a few hours one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle. Each time you complete a charge cycle, it diminishes battery capacity slightly, but you can put notebook, iPod, and iPhone batteries through many charge cycles before they will only hold 80% of original battery capacity." - http://www.apple.com/batteries/
Interesting. Last I looked, the supposed optimal way to prolong a Li-Ion battery was to not let it get below 50% (ie, plug it in to charge when it gets to 50%). I think it was from a link off of Lifehacker a while back. Storing at 40-60% was recommended as well.
I do typically use a smart charger on my NiMHs, and make sure to "break-in" (full discharge -> trickle charge to full -> full discharge -> trickle charge to full) every three months (12 for the new LSDs); I've managed to keep some AAs for well over a decade doing that, albeit I have plenty of spares, so I cycle through them and most are kept at room temperature storage. I used to freeze, but read that that might not be good for them long term (not to mention you have to wait for them to warm up before you can swap, defeating the purpose of spares; also, there's the possibility of thermal shock if you don't warm them up slowly/gently in the fridge).
Wouldn't all modern power management ICs operate the laptop directly from the power supply while float-charging the battery resulting in negligent amounts of heat?
If your cycle count is 223 and you are nearing 80%, then your battery is defective, plain and simple. Apple will replace it. It's happened to me a couple times and Apple took care of it with no hassles.
I had my first macbook's battery replaced. I took it into the apple store for an unrelated problem, the tech noted the awful battery life and asked me how old the laptop was, said, "that's not right...," and grabbed another battery. Nice and easy.
Really? I got a 2006 MacBook Pro in Dec 2006, and each year I had to buy a new battery from Apple as it generally got down to 30-40% capacity.
First time it happened (and was still under warrantee), I took it into Apple, and they said it was normal, and they only replaced batteries if it was defective.
I went through 5 batteries until I got a 2011 MacBook Pro.
How do you prove this to Apple? I have a 1year old MBA that is definitely not getting anywhere near 3 hours on battery, let alone the 7 they advertise.
I have a 2010 MBP 17 which reports 8772 vs. 13000 (39 months old, with 186 cycles) -- it should be around 10000. AppleCare expired 95 days ago and I didn't think to check before then. Presumably I have a decent shot at getting it replaced in variance to official policy, but I'm not sure if I actually care. (I mainly just use it as a desktop.)
I can attest to that: my Macbook white bought on October 2009 (that's 46 months folks) which I used every single day to this very day has 261 load cycles and 91% of original capacity.
Wow, this is an excellent article! Nice visualization of the battery life.
I am quite nervous about the battery sealed inside my own new Macbook. Is it better to attempt to use the battery as much as possible in order to get a new one before the 3 year Applecare Warranty expires? Or to maniacally keep the machine plugged in if at all possible? Or simply not to care? The price of a replacement will be high, and I wonder how many years it will even be possible to replace these batteries.
The thinness of my laptop is amazing, but I would rather have a battery that is not GLUED inside the machine.
I believe Apple charges $199 for a battery replacement, which is definitely not cheap, but might be worth it if you were still happy with the rest of the machine. I'm not sure how long it takes them to do it, though. I'd expect they'd continue to offer that service for quite a few years to come.
As other posters have mentioned, it seems to me like the glued-in batteries don't rapidly decline like the old ones did. I don't have any numbers, though, just impressions.
The best approach is to not worry. The battery is supposed to retain 80% capacity after 1000 charges, which should still be enough for decent battery life. The $200[1] cost to replace the battery is well worth it for two years of moderate to heavy use without worrying about wear.
Not an Apple consumer here, but my netbook battery only lasted about one year, and I attribute this rapid failure to my use of a cheap, (I live off-grid) modified sine wave, voltage inverter, but I have no valid proof of my assumption. As likely a cause for the battery failing to take a charge is the fact that I often ran the netbook until the battery charge depleted to the point of shutting the PC down.
When I bought my current, pure sine, inverter I noticed that my new battery lasted nearly twice as long, but since switching to FreeBSD last year my second battery quickly bit the dust...
I'm expecting the present battery to last somewhere between one and two years, but I'm not taking that expectation to the bank.
To confirm or disprove your idea, you could look at the output of the battery charger rather than the input to it.
In general, AC-DC converters are pretty insensitive to the harmonic content of the AC input because their role is to remove any harmonic content they do find. They do this with huge low-pass filters with corner frequencies well under 1Hz, whether the charger is either linear (unlikely) or switching (much more likely).
When AC becomes distorted, you start seeing harmonics (i.e. contributions at higher frequencies). Low pass filters are progressively more effective at higher frequencies. This is to say, I wouldn't be at all surprised if the efficiency of the charger itself suffered, but the output voltage was unaffected, meaning the laptop was unaffected.
Wait- I thought that was for NiCd batteries and Li-ion batteries where suppose to always be topped off? Furthermore going below 15-20% charge hurts their max charge level?
*By cycle he means running it down and charging it up?
Assuming we're talking about lithium ion chemistry, The most significant thing that will impact the longevity of the battery is heat, and keeping the battery at a high level of charge generates it. In particular, if you're always plugged in and the charging system is keeping it at 100%, this will impact the longevity in a meaningful way.
Not sure about Macbooks, but my laptop has settings to control this. I typically have it setup to only start charging when the charge drops below 40% and to stop at 85%.
Some other points:
- It's preferable not to discharge fully. Very deep discharge can damage the battery, although all modern batteries have circuits to protect against this.
- For long term storage, ~40% charge is best. That's why new phones typically come charged at around this level.
"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 infrequent travel, Apple recommends charging and discharging its battery at least once per month.
[...]
If you don't plan on using your notebook for more than six months, Apple recommends that you store the battery with a 50% charge." [1]
I've only recently started collecting data for my Early 2011 MBP, but I'm starting to see a pretty steep decline. From 72% capacity down to 58% in a little over a month feels like I might be nearing the end of life for my battery.
Yeah, not pegging the axes at zero makes for a much more dramatic graph -- a classic way to lie with data viz. Sometimes it's fine to do that (e.g. because without scaling it's impossible to visually understand some of the data), but the context should be made clear.
That said, the plot of the Macbook Air's battery performance vs. the Macbook Pro's is really interesting. I haven't done the tracking, but this agrees with my anecdotal sense is that my 2011 MBP (likewise a main work+personal system) has had really excellent battery longevity relative to prior Mac/other laptops I've used.
As far as I understand, there are two major factors that will shorten the battery life considerably.
One is heat. This may not be avoidable depending on the computer usage. My mom "plays" Second Life (for english lessons) and her battery barely lasted two years - expanding to the point that the trackpad on her Macbook Pro was sticking out.
Another is leaving the computer plugged in all the time, which will top the battery - and apparently lithium batteries hate that.
Some electric cars have the option to only recharge the battery up to 80%, to increase the lifespan. Would it be possible to do the same with laptop batteries? Perhaps by patching the SMC?
>Some electric cars have the option to only recharge the battery up to 80%, to increase the lifespan. Would it be possible to do the same with laptop batteries? Perhaps by patching the SMC?
My laptop (X1 carbon) does this, I assumed most did. The Lenovo power manager let's you choose when to start charging and when to stop. I start below 40% and stop at 85%.
One other possibility; does the "battery health" metric actually mean the same thing it did four years ago? My 2012 MBA is showing 92% capacity, and seems to last about as long as it did when new. My 2007 MBP shows ~70% capacity, and lasts about an hour; it lasted about four hours when new. I'm not convinced it's that meaningful a metric.
with background information about batteries. It would be great to hear comments about what these sources say. I need a reality check on how to take better care of batteries in rechargeable devices.
> The rate of degradation of lithium-ion batteries is strongly temperature-dependent; they degrade much faster if stored or used at higher temperatures.
That might be related. MacBook Airs get really hot even if you aren't doing anything too taxing.
So, this inspired me to collect similar data on my laptop. I'm collecting a few more data points, internal battery temp, individual cell voltage, etc. I'm estimating 30-60 MB/year at 1 minute intervals. My script is available on GitHub here https://github.com/mikegrb/Battery-Logger
I've set my thinkpad to 'start charging' when below 40% & 'stop charging' when it reaches 60%. I use it with AC power plugged in while the battery floats ~40-60% charge level. Once a month I power cycle it to re-calibrate the battery. It's been going good for the past 3 years. Shows 500 cycle count with 80-90 hrs/week usage & ~80% capacity.
My laptops (two-year-old MacBookPro and three-month-old Thinkpad W530) are plugged in probably 90% of the time I'm using them (8+ hours per day).
From reading some of the other comments here, it sounds like I shouldn't use them while they're plugged in. When they're being used 8-12 hours per day, however, it's impossible to avoid.
My 2011 MacBook Pro is doing a lot better than my 2007 one. With similar use, the older MacBook went through about a battery every year and a half, replacing once they could only hold up an hour or so of charge. I'm up to 750 cycles and holding high at 98% "health".
The OPs MacBook air sounds defective, or at least, under-performing.
How do you even measure max capacity of the battery? Is it by keeping track of the current balance or is there some other direct physical way to do it?
Measuring once per minute seems like massive overkill for a property that changes on a timescale of months, but the interesting question to me is - does it do anything to the life of the battery?
humm, I suppose I should not be too upset then about my Mac Book Pro's battery. It is now a little over 3 years old and I just hit the 500 battery cycles mark this week, about the same time that I noticed my trackpad is no longer working properly. I have had the computer for a while and have not used extensively for over 1 1/2 yrs (have work computer), so I am unsure what it could be, but think it may be the battery. This year we have had a hot weather in the East Coast and my laptop sit out in the changing weather (can't leave the AC on for it), so this may have impacted the battery's lifetime. In general, I can just add that for moderate average use, my Mac Book Pro's battery has lasted quite a bit, but would have liked it to last closer to the 100 cycles promised by Apple's system specs.
[+] [-] JimmaDaRustla|12 years ago|reply
Huge mistake here - he says he cycles his battery! DO NOT DO THIS TO LITHIUM ION BATTERIES! Lithium Ion will last longer by NOT allowing the cells to be fully discharged!
This is the opposite of Nickel Metal Hydride and Nickel Cadmium - these types of batteries DO require a full discharge and full recharge in order to provide a longer life.
In addition, the number of discharges, the temperature, etc all come into play with lithium ion. These thinner laptops are actually lithium ion polymer, where the materials are folded into packs...much more susceptible to the elements, like heat.
Disclaimer: Spent 3 years in the battery field. http://batteryuniversity.com/learn/article/how_to_prolong_li...
Edit: Just want to point out that charging a laptop while using it could potentially create more heat, degrading the battery. I'm not sure what is more damaging - letting the li-ion battery drop below 70%, or charge it while the laptop is being used. So many variables!
[+] [-] mistercow|12 years ago|reply
The crappy thing about that is warranties. Apple, for example (at least last I checked; I don't use a Mac anymore) , would replace a battery if it had under some number of charge cycles (and presumably was less than a year old), but not if it had more than that number.
That means that if you treat your battery really nicely by always keeping its charge between 40% and 60%, and it turns out to be defective, they probably won't replace it because of how many "cycles" it has gone through.
Of course, those kinds of cycles have very little to do with the longevity of a Li+ or LiPo battery anyway. A better metric would be total energy output over time, which would be far simpler to calculate anyway.
[+] [-] jacquesm|12 years ago|reply
As a bit of a re-assurance, the typical laptop power circuit in a laptop using lipo is aware of this and will simply refuse to drop the battery below a certain level so likely the damage is somewhat limited. Still, if you don't need to discharge a battery all the way as far as the circuitry will let you with lipo's you'd better not.
[+] [-] jordanb|12 years ago|reply
Fully discharging any battery isn't good for it. NiCd had the particular problem of "memory" developing though, so going through a full discharge cycle was necessary to prevent the memory forming. It wasn't good for the battery, but it was better than letting the memory develop.
I'm not aware of NiMH developing a memory, so that wouldn't be a good thing to do with NiMH either. I always tried to avoid full discharge of my NiMH batteries and always got a pretty long life out of them.
Really the full discharge cycle is an artifact of the needs of one particular chemistry (NiCd) that became something that "everybody knows" you should do long after it became counterproductive.
[+] [-] thehme|12 years ago|reply
"A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could listen to your iPod for a few hours one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle. Each time you complete a charge cycle, it diminishes battery capacity slightly, but you can put notebook, iPod, and iPhone batteries through many charge cycles before they will only hold 80% of original battery capacity." - http://www.apple.com/batteries/
http://support.apple.com/kb/HT1519
[+] [-] npsimons|12 years ago|reply
I do typically use a smart charger on my NiMHs, and make sure to "break-in" (full discharge -> trickle charge to full -> full discharge -> trickle charge to full) every three months (12 for the new LSDs); I've managed to keep some AAs for well over a decade doing that, albeit I have plenty of spares, so I cycle through them and most are kept at room temperature storage. I used to freeze, but read that that might not be good for them long term (not to mention you have to wait for them to warm up before you can swap, defeating the purpose of spares; also, there's the possibility of thermal shock if you don't warm them up slowly/gently in the fridge).
[+] [-] ferongr|12 years ago|reply
[+] [-] YooLi|12 years ago|reply
[+] [-] aeturnum|12 years ago|reply
[+] [-] berkut|12 years ago|reply
First time it happened (and was still under warrantee), I took it into Apple, and they said it was normal, and they only replaced batteries if it was defective.
I went through 5 batteries until I got a 2011 MacBook Pro.
[+] [-] iloveyouocean|12 years ago|reply
Is this replacement worthy? What am I doing wrong?
[+] [-] mmanfrin|12 years ago|reply
[+] [-] rdl|12 years ago|reply
[+] [-] cliveowen|12 years ago|reply
[+] [-] anu_gupta|12 years ago|reply
[+] [-] nakedrobot2|12 years ago|reply
I am quite nervous about the battery sealed inside my own new Macbook. Is it better to attempt to use the battery as much as possible in order to get a new one before the 3 year Applecare Warranty expires? Or to maniacally keep the machine plugged in if at all possible? Or simply not to care? The price of a replacement will be high, and I wonder how many years it will even be possible to replace these batteries.
The thinness of my laptop is amazing, but I would rather have a battery that is not GLUED inside the machine.
[+] [-] glhaynes|12 years ago|reply
As other posters have mentioned, it seems to me like the glued-in batteries don't rapidly decline like the old ones did. I don't have any numbers, though, just impressions.
[+] [-] bjustin|12 years ago|reply
[1] Estimate, no idea if this is accurate
[+] [-] rayiner|12 years ago|reply
[+] [-] jradavenport|12 years ago|reply
Thanks!
[+] [-] D9u|12 years ago|reply
When I bought my current, pure sine, inverter I noticed that my new battery lasted nearly twice as long, but since switching to FreeBSD last year my second battery quickly bit the dust...
I'm expecting the present battery to last somewhere between one and two years, but I'm not taking that expectation to the bank.
[+] [-] Sheepshow|12 years ago|reply
In general, AC-DC converters are pretty insensitive to the harmonic content of the AC input because their role is to remove any harmonic content they do find. They do this with huge low-pass filters with corner frequencies well under 1Hz, whether the charger is either linear (unlikely) or switching (much more likely).
When AC becomes distorted, you start seeing harmonics (i.e. contributions at higher frequencies). Low pass filters are progressively more effective at higher frequencies. This is to say, I wouldn't be at all surprised if the efficiency of the charger itself suffered, but the output voltage was unaffected, meaning the laptop was unaffected.
[+] [-] voidlogic|12 years ago|reply
Wait- I thought that was for NiCd batteries and Li-ion batteries where suppose to always be topped off? Furthermore going below 15-20% charge hurts their max charge level?
*By cycle he means running it down and charging it up?
[+] [-] ddeck|12 years ago|reply
Not sure about Macbooks, but my laptop has settings to control this. I typically have it setup to only start charging when the charge drops below 40% and to stop at 85%.
Some other points:
- It's preferable not to discharge fully. Very deep discharge can damage the battery, although all modern batteries have circuits to protect against this.
- For long term storage, ~40% charge is best. That's why new phones typically come charged at around this level.
[+] [-] Arjuna|12 years ago|reply
"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 infrequent travel, Apple recommends charging and discharging its battery at least once per month.
[...]
If you don't plan on using your notebook for more than six months, Apple recommends that you store the battery with a 50% charge." [1]
[1] http://www.apple.com/batteries/notebooks.html
[+] [-] uptown|12 years ago|reply
[+] [-] ballard|12 years ago|reply
[+] [-] Silhouette|12 years ago|reply
[+] [-] saidajigumi|12 years ago|reply
That said, the plot of the Macbook Air's battery performance vs. the Macbook Pro's is really interesting. I haven't done the tracking, but this agrees with my anecdotal sense is that my 2011 MBP (likewise a main work+personal system) has had really excellent battery longevity relative to prior Mac/other laptops I've used.
[+] [-] outworlder|12 years ago|reply
One is heat. This may not be avoidable depending on the computer usage. My mom "plays" Second Life (for english lessons) and her battery barely lasted two years - expanding to the point that the trackpad on her Macbook Pro was sticking out.
Another is leaving the computer plugged in all the time, which will top the battery - and apparently lithium batteries hate that.
Some electric cars have the option to only recharge the battery up to 80%, to increase the lifespan. Would it be possible to do the same with laptop batteries? Perhaps by patching the SMC?
[+] [-] ddeck|12 years ago|reply
My laptop (X1 carbon) does this, I assumed most did. The Lenovo power manager let's you choose when to start charging and when to stop. I start below 40% and stop at 85%.
[+] [-] GuiA|12 years ago|reply
I thought modern batteries had mechanisms in place to prevent that?
[+] [-] rsynnott|12 years ago|reply
[+] [-] post_break|12 years ago|reply
[+] [-] tokenadult|12 years ago|reply
http://batteryuniversity.com/learn/article/how_to_prolong_li...
http://lifehacker.com/5875162/how-often-should-i-charge-my-g...
http://www.latimes.com/business/technology/la-fi-tn-five-fre...
http://gigaom.com/2013/06/06/new-ti-chips-speed-charge-times...
with background information about batteries. It would be great to hear comments about what these sources say. I need a reality check on how to take better care of batteries in rechargeable devices.
[+] [-] ahoge|12 years ago|reply
> The rate of degradation of lithium-ion batteries is strongly temperature-dependent; they degrade much faster if stored or used at higher temperatures.
That might be related. MacBook Airs get really hot even if you aren't doing anything too taxing.
[+] [-] mikegrb|12 years ago|reply
[+] [-] enscr|12 years ago|reply
[+] [-] aroman|12 years ago|reply
I have more than double his cycle count at 569. My battery is at 85% capacity.
I'd say your battery is defective, or you were doing something to it that caused it to degrade more rapidly.
It's also a little unnerving that the 2009 MBP has an apparently far superior battery, despite Apple's explicit claims to the contrary.
[+] [-] jlgaddis|12 years ago|reply
From reading some of the other comments here, it sounds like I shouldn't use them while they're plugged in. When they're being used 8-12 hours per day, however, it's impossible to avoid.
[+] [-] nwh|12 years ago|reply
The OPs MacBook air sounds defective, or at least, under-performing.
[+] [-] sengstrom|12 years ago|reply
Measuring once per minute seems like massive overkill for a property that changes on a timescale of months, but the interesting question to me is - does it do anything to the life of the battery?
[+] [-] rcthompson|12 years ago|reply
I guess that makes me a ... power user? ;)
[+] [-] thehme|12 years ago|reply