With batteries being such an integral part of smartphones, it’s little wonder that extending the period between charging and battery replacement has led to many theories and outright myths about what may affect the lifespan of these lithium-ion batteries. To bust some of them, [HTX Studio] over on YouTube has spent the past two years torturing both themselves and a myriad of both iOS and Android phones to tease out some real-life data.
After a few false starts with smaller experiments, they settled on an experimental setup involving 40 phones to investigate two claims: first, whether fast charging is worse than slow charging, and second, whether limiting charging to 80% of a battery’s capacity will increase its lifespan. This latter group effectively uses only 50% of the capacity, by discharging down to 30% before recharging. A single control phone was left alone without forced charge-discharge cycles.
After 500 charge cycles and 167 days, these three groups (fast, slow, 50%) were examined for remaining battery capacity. As one can see in the above graphic for the Android group and the similar one for iOS in the video, the results are basically what you expect. Li-ion batteries age over time (‘calendar aging’), with temperature and state-of-charge (SoC) affecting the speed of this aging process, as can be seen in the SoC graph from an earlier article that we featured on built-in batteries.
It seems that keeping the battery as cool as possible and the SoC as low as possible, along with the number of charge-discharge cycles, will extend its lifespan, but Li-ion batteries are doomed to a very finite lifespan on account of their basic chemistry. This makes these smartphone charging myths both true, but less relevant than one might assume, as over the lifespan of something like a smartphone, it won’t make a massive difference.
The graph on the top shows that fast charging does – contrary to what the article says – not degrade the batteries faster. The capacity loss with fast charging was lower than with slow charging. But I would expect that the effect is not statistically significant as the variance is quite high.
Yeah, after reading the article, I’m still not sure what the results were (now I have to actually watch the video).
And using the statement “…the results are basically what you expect.”, in an article about challenging popular thought is less than useless; it is actively confusing.
Sometimes it can make a dramatic difference.
Once upon a time I took part in a family quarrel which, unfortunately, escalated. Family members who were not aware of “ACAB” slogan and the simple fact of life that cops are NOT your friends, decided to get state involved in a matter which should’ve been settled internally. The result was loss-loss for everyone as cops, acting against family pleas and wishes, decided I should be taken to a mental hospital for “observation”. I guess it’s called “hospital” only for legal reasons as in practice it was more of a state-run detention facility where you spend day after day locked up in a room which is watched 24/7 by staff and their CCTV. There’s nothing to do except lie in bed and stare at the walls. To keep you sane in an insane asylum, twice a day they give you a healthy dose of antipsychotics and muscle relaxants which make you feel extremly drowsy. I had to fight myself just to stay awake.
After first five days of doing nothing staff finally determined I am “stable enough” to be given back my smartphone (although they took away both SIM cards). I could use it from morning (after breakfast, around 8 AM) until bedtime (around 9 PM). I had to hand it over for the night though.
I was SO GLAD that I always took care not to overcharge my phone, to use 500 mA charger, to disable all the bloatware and apps which do nothing useful. Wardens were supposed to charge our phones overnight, but they often “forgot” and laughed when asked about it. Having a battery which is not excessively worn and will easily last two days of use really came in handy.
I have a library full of interesting books on my phone. While the next 25 days of being kept in a drugged (pretty much zombified) state were still miserable and every day I had to struggle just to stay awake, at least I could read plenty of interesting books on software engineering, electronics and other topics. This helped me remember who I am, stay strong, stay focused and not get “broken” awful treatment from the hospital staff. Unfortunately some of the more “normie” guys with whom I’ve done time in a room together were not so lucky…