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?

      • jbk@discuss.tchncs.de
        6·
        3 days 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!

  • davidgro@lemmy.world
    51·
    4 days 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
      11·
      4 days 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)

    • SqueakyBeaver@lemmy.blahaj.zone
      2·
      3 days ago

      Not entirely sure if this would apply in your case, but for future reference you can sort of “recalibrate” the battery percentage by:

      1. charging the device to 100% and keeping the charger on for a while (normally a few hours)
      2. drain the battery until the device shuts off
      3. charge the device back to 100% without unplugging it (keep it connected for a few hours again just to be sure)
      • rumba@lemmy.zipEnglish
        3·
        3 days ago

        That generally works when replacing OEM with OEM. But when you replace a 3000 milliamp hour battery with a zero lemon 10,000 milliamp hour pack, Samsung’s algorithm just couldn’t sort that out.

        My old Note 4 ran for years with a giant zero lemon pack It always thought it had about 27 hours worth of life at full charge, but I would constantly get 40 hours plus.

      • davidgro@lemmy.world
        1·
        3 days ago

        It didn’t help that old phone, there seem to be limits to just how much adjustment it can make (including to dying batteries with less capacity also)

      • SuperSpruce@lemmy.zipOP
        12·
        3 days ago

        I don’t like doing that because it wears the battery. Better to have slightly inaccurate percentages than to actively make the long term situation worse

        • infeeeee@lemm.ee
          4·
          3 days ago

          1 up-down cycle doesn’t wear the battery, negligible. It would only count if you would do this every day. It’s recommended to calibrate a new battery

        • LilB0kChoy@lemm.ee
          21·
          3 days ago

          I was under the impression that’s not how LiIon batteries work. Was it a NiCad or some older type?

          • davidgro@lemmy.world
            1·
            3 days ago

            I think they are referencing how Li-ion batteries just generally have a limited number of charge cycles, so they don’t want to waste a whole one.

            • LilB0kChoy@lemm.ee
              1·
              3 days ago

              That’s why I asked. I knew about the cycles but I’m not aware of it causing any additional wear. I thought maybe there were new findings recently. I’ll have to go look myself, just to satisfy my curiosity.

  • 𝕽𝖚𝖆𝖎𝖉𝖍𝖗𝖎𝖌𝖍@midwest.social
    91·
    4 days ago

    No. If mine goes single digits, it’s a crap shoot. It can take 30 minutes to go from 20% to 10%, but it will shut down 5, 3,or 1 minute after it hits 10%.

    I have never had a phone where the developers were such shit at coding the voltage estimation, or designing the hardware doing the measuring, or whatever combination makes it so random.

    Never buying another Samsung again. Mainly because if the uninstallable bloatware, but crap like this battery thing is also infuriating.

    • CmdrShepard42@lemm.ee
      7·
      3 days ago

      It’s a bad battery that’s causing this issue. You can’t calculate for a battery that’s out of spec which is why they drop from 30% to 2% in minutes or shutoff when you still show 20% remaining. The voltage sags below the minimum capable for the hardware.

    • SolOrion@sh.itjust.works
      4·
      4 days ago

      I’ve been using exclusively Samsung phones for a long time- is any battery % below 15 being a crapshoot not a normal android thing? I remember it happening a long time ago with my LG phone too, so I kinda just assumed it was difficult to estimate battery capacity once it got low.

      • 𝕽𝖚𝖆𝖎𝖉𝖍𝖗𝖎𝖌𝖍@midwest.social
        2·
        3 days ago

        This is my first Samsung. I’ve had a few Pixels, HTC before Pixel, a Sony… a variety of phones. Low single digits, sure. And I’ve seen phones where the seem to have a consistent rate of drain until they get low, then suddenly start dropping faster. But this Samsung is a new level of inaccuracy. I was using it once and it got to 7% while I was finishing a writing a response, and it just turned itself off. I know, because I was nervously watching the battery level; it just shut down at 7%.

        I don’t think comparing the really old phones to new ones is fair because battery tech and software changes so much, but my previous Pixel was really good - at 2%, I was playing with fire, but a long as I plugged it in before that I was safe. With this Samsung, as soon as it hits 10% it’s Russian Roulette.

  • PhilipTheBucket@ponder.cat
    111·
    4 days ago

    Measuring the amount of battery that’s left is always a total crapshoot. I don’t know for sure but I strongly suspect that they try to smooth over the phone’s inability to tell what’s going on by showing a gradual decline in the battery level regardless of what is happening, adjusting the speed of the decline as time passes depending on what vague and incomplete information it’s able to gather about what it actually happening with the battery.

  • some_guy@lemmy.sdf.org
    3·
    3 days 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.