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Studying the Slow Decay of a Laptop Battery For an Entire Year
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."
You're discharging it wrong, don't do that.
Let's see the comparative graph where you did identical tracking over time for both, instead of detailed now against casual before, which seems a bit weak. I'd also like to see how you factor out the constant logging's effect as well.
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.
1) It's "without further ado," not adieu.
You're making much adieu about nothing.
Cockadieudledoo!
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.
Presumably the same reason someone pays big bucks to drink coffee made from coffee beans that have been in a civet's anus.
Apple get the same batteries from the same places everyone else does. They're as fungible as AAs at this point.
No kidding!!! What do you say at this point?
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
I love studies with a sample size of one. No statistics, no variability. Definitive.
Calculated battery capacity is an estimate, nothing more, used by power management to decide when the computer should be force-slept, then suspended to disk to keep from damaging the battery (ie, it's not useful to wake up too late from sleep to do the suspend-to-disk.)
The SMC's estimate is just that: an estimate. Errors build up over time, and certain things fake it out a bit. For example, note the capacity, unplug the laptop, use it for 30 minutes, plug it in. Immediately the value will be different. It'll change again when fully charged. Your battery capacity didn't actually change. Even in a perfect world, since batteries have internal resistance, capacity gauges can never be perfect(if you draw at X you'll get less power out than if you draw out at X*0.8), and the battery's capacity varies with temperature. Battery degradation is impacted by temperature as well, so unless you're controlling for temperature of the pack, this was a completely useless endeavor. The only way this would have been useful would've been to cycle several (probably a dozen or more) batteries on lab-grade equipment in a temperature-controlled environment.
The noise and big upward swings alone should tell you that using the SMC's estimate for the purposes of statistical analysis or trending is virtually useless.
The stupid shit I see "enthusiasts" of any product obsess over is absurd. The time wasted on such an exercise far outweighs the impact it possibly could have had on the author (and probably even 9-10 other people combined.) The batteries last for well over 6 hours. Most people using a ultrabook with the battery life of a Macbook Air have plenty of opportunities to charge their machines during the course of a day.
Please help metamoderate.
It shows that you don't know the details of Apple's power delivery architecture. Magsafe-equipped Apple laptops are intentionally crippled in that the charger is artificially disabled if you use an unauthorized one. There's a chip in the magsafe plug that connects to the middle pin and is interrogated by the system management on the mainboard. If the interrogation fails, you can still use the power source, but the charger is disabled.
All it takes not to charge the battery is to cover the middle magsafe pin. I've done it by keeping in use one charger with a bad magsafe plug where the chip had died. Died how? Ah, exposure to the saliva of a 1 year old, he liked to lick those plugs, they admittedly taste "funny" since they are energized :)
That way you have the best of both worlds: you don't lose your work if the magsafe plug is kicked loose, and you don't charge the battery if you don't want to. Win-Win.
A successful API design takes a mixture of software design and pedagogy.