I was just doing random stuff on my phone and went to click a button near the top right of the screen, and was mildly horrified to see “1%”, so I immediately put it into the charger, where the phone promptly started showing “0%” for the next ~30 seconds. The phone never died.

Has this happened to any of you?

  • davidgro@lemmy.world
    42·
    2 months ago

    Yup. Battery percentages are an abstraction over the actual voltage and remaining amp-hours - it’s a complex formula which requires calibration and can easily be a bit off.

    On one of my first smart phones, after replacing the battery with a much bigger one (both capacity and physically) it would still use the old formula, so it said 100% when halfway charged and after fully charging, during use it would stay near 0 (or at it - can’t remember well) for half the actual usable time. I found an app that could show the actual voltage in the notifications, which helped a lot. (When it went under 3.5 or something, I knew it was almost out) But that number also varied with how much power was being drawn, etc.

    • entwine413@lemm.ee
      10·
      2 months ago

      Yeah, more amps being drawn will cause a larger voltage drop. I got to play around with this with my old vapes that had DNA chips. The software suite allows you to generate battery profiles by discharging the battery over an hour or so at different wattages to get the discharge curve. I even built my own resistor group on a heat sink to run the tests (4x heavy duty 1ohm resistors in parallel)

      • jbk@discuss.tchncs.de
        4·
        2 months ago

        i found a debug command in Android’s battery service: cmd battery set level 99. probably only accessible via adb shell. don’t do this without charging your phone unless you’re in for a surprise!

  • some_guy@lemmy.sdf.org
    3·
    2 months ago

    Any quality phone will / would “under promise and over deliver.” What I mean is, you lie about being at zero charge when you really have one or two or three percent left to give the user time to get to a charger. This is better than turning off because it allows time for circumstances that don’t allow the user to plug into a charger. Having a bit of breathing room means that one can call emergency services while on the way to plug in, for example, rather than being screwed because it’s a ten minute walk home.