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  • How Can I Limit Battery Charge to 80%

yourmother
I set the alarm clock every time i plug in for charging. Its the only method i could fathom.

I use a 5v1a adapter and that can charge the phone 10% every 23 minutes. I set the timer according to my desired charge level. You get used to it pretty fast.

It makes sense to limit the maximum charge of a Li-ion battery to a lower voltage than the one decided by the manufacturer for people who would like to use their battery longer than what is targeted by the
manufacturer. See the first answer to this question on stack exchange for an indepth explanation.

I would also love such a feature but it's only possible on the official operating system as far as I know. Another cool feature would be the possibility to prevent charging above 60%, for example for using the phone as a cheap 5G router and leaving it at home always plugged to its charger.

you could also use an external device like https://chargie.org
it sits between the wall charger and your phone and it communicates with the phone via BT.
in the Chargie app, you can specify values and once these valules are met, the charging stops.

using it since years and the batteries barely degraded. i am quite happy with it
note: i am not related with the company behind chargie or to the product in any way. i am just a happy customer

Samsung has a feature called "Protect Battery" since Android 12 (other manufacturers may also have it). When it is switched on, the charging process stops at 85% (i.e. not only the threshold described by bookreader , but also the 85% display value).

If you are out of range of power sockets for a longer time, you can simply deactivate "Protect Battery" beforehand and the device will charge to 100%.

If this really helps to extend the life of the battery, I would also think it would be cool to have such a toggle on GrapheneOS.

    Murcielago
    Kindly ask to not point to bookreaders post, because it is just not true.

    If you still question if and why a li-ion battery should be operated in a range between 20% - 80% read the essay on batteryuniversity (link above)

      bookreader Why do so many manufacturers have options to limit charge to 80% though? MacBooks and iPhones both limit charge to 80% for as long as possible (until they think you're likely to remove them from the charger). OnePlus phones, Pixel phones running stock firmware, and Samsung phones all have this by default as well.

      Why does everyone do it if it's "not a thing"? Everything I've read says that batteries typically degrade more quickly as the voltage is higher, and many manufacturers seem to believe this to be true as well. While I do trust the charging circuit to behave sanely, the charging circuit ultimately has to pick some voltage and say "this is the top." I might want the top to be somewhere else. As you said, the chemistry doesn't understand percentages, so there's no magic, 100% agreed upon value for max charge voltage. This is why it makes sense for it to be configurable. If the chemistry knew about percentages, it wouldn't make any sense for it to be configurable, because there would be a universally known "correct" top voltage. But there's not.

      DaRon Many thanks for the link. My point was not so much whether his statement was right or wrong, but that I would find it practical to only charge the cell phone up to 85% and, if necessary, up to 100% by simply flipping a toggle.

      bookreader
      Can you explain it, please? For the stupid among us....
      I am really curious and interested

      i am using the accubattery app, not because of the 80%, the app beeps when the battery is charged to 80.
      it cannot stop charging however, it has to be unplugged manually

      bookreader Is that why? I thought maybe it was because of the substantial body of peer-reviewed research showing that battery degradation accelerates with increased voltage. But I guess if we can achieve results that are based on science we can't complain, even if the results were achieved due to the complaints of stupid people.

      Kudos to all the stupid people demanding research-supported science-based improvements to our phones!

      Hi!
      Have you tried install magisk?
      There's a module called acc(advanced charging controller) that can be modified to limit charge percentage.

      yes, I know and I am quite clear that purists will come to say that installing root goes against the whole philosophy of the project, but it is my cell phone, so be more open minded.
      Excuse my toxicity.

      dgzeij bookreader

      These comments aren't helpful.

      For many people, phone batteries last longer than other parts of the phone do. This topic isn't worth such heated exchanges. My suggestion is to share your thoughts or any articles or research you have found helpful in a respectful manner, let others draw their own conclusions, and let them use their own devices the way they'd like.

      To answer the original question, it's not possible to automatically limit charging to 80% on GrapheneOS, even with a third party app.

      Stock Pixel OS does offer adaptive charging, but that is also not possible on GrapheneOS.

      On the point of whether it makes sense to limit charging to 80%, I don't see any value in continuing that discussion, since everybody has had a chance to make their point heard, and it has since descended into bickering.

      If any one is looking for sources about battery degradation, there is a decent paper from a few years ago that gives a nice run-down with lots of references. https://www.sciencedirect.com/science/article/pii/S2352152X19314227

      A few highlights:

      "Zhang et al. show that a typical laptop battery stored at 25 °C and 100% SoC will irreversibly lose 20% of its capacity each year."

      "Hoke et al. argue that if battery temperature and charge-discharge cycling are kept constant, minimizing time spent at high SoC minimizes degradation. If the next day's energy requirement is known, the battery can be charged to the minimum required level, rather than to the conventional full charge."

      "Lunz et al. show that battery lifetime can be increased by reducing the target SoC to lower values, or by minimizing rest periods at high SoC."

      "Because standby times dominate battery operation, there is a large opportunity to increase battery lifetime by adjusting the time and frequency of charging (smart charging)."

      I'm locking this thread, because of the points raised already, and the continued bickering.

      I would also recommend caution when citing academic references which refer to SoC of a Li-ion battery. There are a number of different definitions of SoC, so it's important to understand which one is being referred to in which article.

      treequell locked the discussion .
      6 months later

      We plan to implement customization for charging. It requires doing research/design work to come up with a sensible approach rather than simply what other operating systems are doing. There's a lot of evidence that providing control over the minimum capacity to begin charging and the maximum charge capacity would be useful for people who want to sacrifice a bit of short term battery life to preserve it better in the long term. Charge rate is already throttled based on capacity where it greatly slows down as it approaches 100%. it's also already throttled based on heat. We have most of the standard battery health features used on Pixels, just not the adaptive charging feature which guesses your schedule and slows down or limits charging in some cases.

      A lot of people are passionate about this topic and there's conflicting information. GrapheneOS developers didn't participate in this discussion and none of it before this post is official info from the project. Current lack of non-standard features in this area doesn't mean we don't want to it, but we generally agree with the standard approach other than adaptive charging often not doing what people want/expect. Providing a bit more control over the standard approach rather than layering another on top may be exactly what's needed. Controlling how much it slows down based on heat, charge capacity, etc. along with controlling how high it goes is probably all we really need. Expecting people to manually set a scheduled time for charging over and over is unrealistic and conflicts with charging whenever you can.