Today I'm revisiting a topic I've been fascinating (obsessed?) with for many years: my laptop battery (e.g. see past blog posts here, here, here, here...)10 Years of Data
I started semi-regularly keeping track of my laptop battery's health using coconutBattery back in 2009, with my big 15" MacBook Pro. Once I figured out how to automate the process myself with cron, I began in late 2012 keeping a record of my battery status every minute I used my laptop. Here is the complete 10-year record of my laptop(s) battery charge capacity:
the "cost" of keeping battery data for every minute of use over many years is only a few hundred Mb
Comparing Mac Batteries
For the hardware nerds (incl. me) who are curious how these batteries hold up over many years of daily use, here are all 4 computers' lives overlaid, including the 2016 MacBook Pro (w/ Touch Bar) I am using to write this:
Interesting stat: the standard deviation of the capacity data (about a ~14 day rolling mean) is a scant 0.6%!My 2009 MacBook Pro really started to decay at the end of its life (I used it a couple more months past this data). The 2012 Air (red points) was a definite anomaly. In fact, after I blogged about this problem, Apple reached out and replaced the computer with a new model - my favorite computer of all time, the 2013 MacBook Air. Amazingly this workhorse is still under daily use, on loan to a student!
I've given the 2016 13" MacBook Pro with TouchBar a lot of grief, as I've had many problems with it. However, the verdict seems to be in: the 2016 MacBook Pro's battery appears to be the best I've had over the past 10 years! After 2.5 years of use, it's still claiming to hold 90% of it's original charge! I wonder... if we start making batteries that substantially outlive the host computers, will they be up-cycled? Could we start to see removable Mac batteries again? Pure speculation.
I have changed...
Despite all the advances in hardware over the past 10 years, I think the data suggests the biggest change is with myself... or at least how I use my laptops. Consider this slightly hard-to-read figure, showing the distribution of charge fraction (how full the battery is) for my past 3 computers. For all computers I tended to keep them charged most of the time (peaks near 1), but for the 2016 MBP I keep it fully charged (i.e. plugged in) almost always... which is not surprising since I have chargers at home and at the office. These are really more portable workstations, and less "laptops" for me now.
I make the conscious effort to not work in the evenings
Here is the now-classic digital fingerprint, first popularized by Stephen Wolfram, of my life: 1 dot for every data point, tracing the time of day versus years of use. This is a classic diagram for examining the "quantified self". Obvious big features are: I sleep at night, I take a break near dinner, etc. You can also see some seasonal variations, especially during the 2nd half of grad school (2013 MBA, purple), where I seem to work later in the winters (probably getting ready for the AAS conference).
There's some big data errors present in the 2016 MBP data (blue), which show up as stripes here (i.e. every minute was recorded). My laptop appears to have occasional insomnia? Strange... (note: I've tried to remove these spurious days from here on). I don't think this figure tells the right story, however.
My daily computer usage has changed too - this is the figure I'm most proud of. Here I show the time of day used for each computer. Despite using the iMac at work during the day, my evening laptop usage has dropped a TON. Reason: I make the conscious effort to not work in the evenings! This may seem silly to many, but for an early-career academic it's a serious choice.
My work day is now a bit shorter, with a slightly later start, and an earlier end. Reason: this is largely driven by my toddler's daycare schedule. Yay!
But, my workday is also more consistent. See how there's no dip for lunch? I'm in lunch meetings or eating at my desk most days now. Boo.
Most interestingly (to me), when you fold this data over days of the week (0=Monday, etc), you can see a very big change as well. While I always was fairly good at working less on the weekends, now you can see I have almost NO computer usage on Saturday and Sunday. I also seem to work a LOT more on Friday mornings than I used to... but I think this is because my wife and I work from home some Fridays, and so my laptop usage would seem higher (since the iMac is at my office).
Conclusion
There are many metrics one could use to trace their digital lives - social media activity, emails, screen time (basically equivalent to my battery record). Given the explosion of use my iPhone has seen over the past decade, I'm very glad to see Apple (and others) are finally getting on board with providing this data to users, and (maybe) helping them use their devices more mindfully. As I've written before, the "cost" of keeping battery data for every minute of use over many years is only a few hundred Mb (and probably could be 5-10x smaller if I cared to compress it at all), and so I encourage Apple to make the usage archive part of every computer's "permanent record".
As always, all the Python code to do this analysis and make these figures (including the very clumsy parser I wrote for the ugly battery log data) is on my GitHub! Also, the simple cron script I use is also posted, including detailed install instructions, if you want to try this yourself.
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