Studying the Slow Decay of a Laptop Battery For an Entire Year 363
First time accepted submitter jradavenport writes "I've been keeping a log of the health of my MacBook Air battery for the past year, taking samples every minute I use the computer (152,411 readings so far!). This has allowed me to study both my own computing/work habits, but also the fascinating rapid decay of battery capacity. Comparing it to my previous 2009 MacBook Pro, the battery in this 2012 Air is degrading much faster."
Love my MacBook Air, hate the battery (Score:5, Informative)
I got 10 hours of battery life on my 2011 macbook air when I first got it. I don't just mean 10 hours of it sitting idle either. I could get 7 hours of continuous play of movies. Then Mountain Lion came out and I was lucky to get 3 hours tops. That lasted 6 months until they "fixed" it and I was able to get 5 again. Now in I can consistently get 4 hours with it sitting mostly idle.
I love the machine but I hate that I cant change the battery myself. I'll have to pay the Apple tax to get this fixed. I am holding out hope for Mavericks though, hopefully the power saving features can breathe some new life into this thing.
Re:Survey says... (Score:5, Informative)
We live with what we got now. That is life. But ...
Within a few years that will change with lithium-sulfur batteries if the lab geeks have anything to say about it.
http://www.extremetech.com/extreme/157525-new-sulfur-based-battery-is-safer-cheaper-more-powerful-than-lithium-ion [extremetech.com]
Letting the battery cycle? (Score:4, Informative)
Most modern lithium batteries should *not* be cycled or discharged "fully"--such a practice degrades the battery capacity quite rapidly. I think the practice of fully discharging the battery comes from the NiMH-type rechargeable AA(A) batteries.
Yeah, sometimes people recommend fully discharging a lithium battery during operation so that the monitoring software can recalibrate it's battery power meter to adjust for the decline in total capacity, but I'm not sure it's worth it.
As mentioned earlier, temperature is a big factor as well. Maybe Haswell will save the day...
Re:Ah, I see the problem. (Score:5, Informative)
You have to do that every once in awhile if you want the battery status indicator to be correct. This is because the voltage curve is so flat there really is no other way to determine level of charge other than to count power out and calibrate what the battery should hold periodically.
Re:Love my MacBook Air, hate the battery (Score:5, Informative)
What do you mean you can't change the battery?
Do you not own a screw driver? And you call yourself a geek.
http://www.ifixit.com/Guide/Installing+MacBook+Air+Models+A1237+and+A1304+Battery/848/1 [ifixit.com]
Re:Laugh (Score:4, Informative)
Bad batteries something Apple is famous for, RAM fixed to the logic board, insecure and buggy OS, and a host of other complaints makes me wonder why anyone pays the premium for Apple any longer.
Maybe because that hasn't been most peoples' experience [osxdaily.com]? I have a MacBook Pro that is almost 3 years old and the battery is still almost as good as the day I bought it. Of course, I make sure to run mine down once a month as recommended.
Re:Power storage that doesn't degrade... (Score:5, Informative)
Because of the whole host of other problems with that suggestion.
Here is a small set of them, there are many more
1. expensive fuel cell
2. low density storage unless you go with expensive metal hydrides
3. H2 embrittles everything
4. far cheaper to make H2 via steam reformation of natural gas than electrolysis
Perfectly valid (Score:5, Informative)
I love studies with a sample size of one. No statistics, no variability. Definitive.
every apple product (Score:2, Informative)
Re:Love my MacBook Air, hate the battery (Score:4, Informative)
If your battery was great until a software update, then the problem probably isn't the battery but the software, and replacing the battery won't solve your problem.
Re:Survey says... (Score:5, Informative)
Re:Two Things (Score:4, Informative)
Re:Laugh (Score:3, Informative)
Though, to be honest, I've rarely ever installed additional RAM in any PC I had - given its cost, it's usually cheaper to buy the max up front than in a few years when memory standards change and it's difficult to buy it cheaply (e.g., DDR or DDR2) - especially the larger modules - they either simply stop existing or are still wildly expensive years later.
I've never bought a Mac with RAM fixed to the logic board; and with pretty much every Mac I've ever bought, I've bought it with the minimum RAM configuration and then gone third party to top it up either immediately or within 2 years -- usually saving a few hundred dollars. The one thing Apple IS known for is overcharging for RAM. They've always done this, even back in the SIMM days. They argue that it's because they have higher standards, and thus you're only getting the best RAM from them. I've NEVER had a problem with using properly sourced cheaper RAM with a Mac.
Re:Survey says... (Score:5, Informative)
PROTIP: Remove your laptop battery if you are running from the mains most of the time and keep it in a cool drawer somewhere.
MacTip: DON'T. Your Mac automatically scales back its clock speed to 1 GHz tops. Brownouts can crash your computer immediately because there is no battery to supply power. Magsafe connectors and no battery are an obvious bad combination. And you'll get dust into your computer.
Re:Ah, I see the problem. (Score:5, Informative)
If you don't care if the battery gauge is inaccurate, you should never cycle the battery completely. Lithiums thrive with frequent top-ups.
Unfortunately, having a useful gauge is handy so it's useful to cycle the battery occasionally.
I rarely use battery power deep into a battery's cycle so I don't worry too much about it.
Re: Here's the real problem (Score:4, Informative)
For example if a wheel is making noise have it checked either by a shop or your self if you know what to look for and make the noise go away:
It might be the pad wear indicator just starting to scrape (replace the brake pads and enjoy your new found stopping power) It might be that you have run the pad backing into the rotor in which case you avoided a very bad problem but you might need you hearing checked since it got this far
The bearing might just be a little dry in which case greasing it solves the problem
If the bearing is completely dry you just avoided a very bad problem
If the needle bearings are gone you just avoid a very bad problem but why did you wait so long as it should have been making nose for a while so go get your hearing checked