I used to use a Galaxy Tab A 2019 for torrenting until it stopped getting updates. While torrenting, it would be plugged in for days or a week at a time.
I still use the tablet daily for off-line games and haven't noticed any battery issues.
I used to stop charging at 85% for all my phones but I have enough evidence (at least for me) that leaving a modern android on charge is a non-issue.
[deleted] in that case if you do the same on pixel with grapheneos after something like 2 or 3 days it will start discharging from 100% and then stay at 80% with a message "Charging optimized to protect your battery" it is a similar but different feature from the one that OP speak about
collector yea i edited that message, but multiples brands say the same, i know of Apple, Google, Samsung and Huawei at least, i have read the same in the huawei p8 manual despite of it not having that feature at the time they still recommended to charge it to 80%, so i'm not sure what to think about it, why would huawei said that if they didn't even had a feature to limit the charging at that time?
anyways i would not use that feature so i don't mind, i just charge to 100% and unplug
collector So, I gave it a read to the article attached in the link and first of all thanks akc3n for detail explanation. But, I do have a doubt regarding the wireless charging overnight :
As explained in the article, when the device is 100% charged and the lockscreen is displaying the status as "charged", the battery is in idle maintenance mode and the phone is powered via external source (here in my case apple magsafe charger). I know, for sure, that when magsafe charger is charging something (especially mobile phones), it tends to get warm. But, when I wake up in the morning, I see my phone on the charger at 100% and I find magsafe charger at room temperature.
This observation does not sit well with what was mentioned in the article, as if the phone was getting its power from external source and not battery, the magsafe charger should have been a ltl warmer than room temperature. Could anyone explain this or mention something which I am missing right now?
dsjvhjdjhgvcjhsdc More current --> more heat. While the charger is just supplying enough power to keep the phone on, it is supplying a lot less current than while also charging the battery, hence the heat generated is a lot lower. Keeping the phone on draws very very little current.
The charger should produce far less heat than a discharging battery, since there is no chemical reaction, therefore I wouldn't expect to be able to detect any heat from the charger just by touch in these circumstances.
I really hope to see this feature in GOS.
I have personally noticed a big increase in the battery life (over time) of my devices (laptop, smartphone) since I no longer systematically charge them to 100%.
My 2015 Dell XPS Laptop still has its original battery and still lasts several hours unplugged. The BIOS generally prevents charging beyond 90% and in any case does not allow charging to be resumed when the battery has not dropped below a certain level.
Here we have people confusing the possibility of limiting charging with the role of the bms.
The bms, which is hardware, protects the battery by preventing overcharging, deep discharge, overheating, etc. But it's not a charge limiter. There will be no danger in charging your battery to 100% every day, but its lifespan will be shorter.
On the other hand, I strongly doubt the usefulness of not using fast charging (apart from safety issues).
The Pixel range is already very conservative in terms of fast charging, and above 50% the charging speed is significantly reduced, and the temperature is well controlled.
Phones already have this! If you are on a USB-C PD charger (atleast with the official one) it will give the device just as much power as it needs.
If the battery is charged, this means the phone will not even use it but run off the charger.
We dont need such a charge limiter as there already is one.
missing-root You don't need a PD charger to gain charge protection. Charge limiter is part of the PMIC inside the phone.
missing-root Unfortunately, this clear-cut opinion on battery use is only shared by Graphene Os.
They talk about a bms that protects the battery, but they say you need the Google charger. The bms protects the battery whatever the situation, even when it's not being charged!
Of course the battery doesn't stay in charge once it's at 100%, but that's not the problem.
The majority of devices with lithium batteries have the option of limiting charging, precisely to avoid premature wear and tear associated with constant full recharging.
Examples include ecoflow batteries, recent Samsung phones, electric vehicles, even some flashlights, etc. But of course, a pixel with Gos is not concerned. 😏
The difference between a bms that protects the battery (but allows a full recharge cycle) and a charge limiter doesn't seem clear to everyone.
Some sources related to the AccuBattery project: https://accubattery.zendesk.com/hc/en-us/sections/202397985-AccuBattery-Research-and-Methodology
missing-root I've heard a lot of people say this (and yes, I've read akc3n's article in full many times) but I haven't seen any proof.
Much research has been done (already linked) showing that a charge level of around 4.05V/cell provides extreme benefits to total battery life (not just cycles but total lifetime).
I'd like to at least see some data showing that this is the maximum charge given to e.g. Pixel phones at 100% based on the actual phone or a reliable app reporting as such. In my experience the charge at 100% is 4.2v or higher.
If someone can show that Pixels are limited to 4.05v then I'd be impressed.
I think a feature that would shut off a phone at 25% would be worth adding as well.
Simply by reading the title, the easiest solution to this problem is to charge it 30 minutes before bedtime.
[deleted]
Yes, or 45 Min. before bedtime, when the battery has about 30–35 % remaining charge.
Charging to about 70% takes about 45 minutes and if you then switch on flight mode and low-power mode for bedtime, the Pixel Phone still consumes a whopping 2-3% instead of zero per cent as expected. For doing nothing in the night!
I guess what the author tries to say is that if you use the normal charger overnight, your battery will stay in idle maintenance, which is better for the battery than normal discharge over night.
If you only charge before going to bed and then leave it alone, the battery will be worn down by normal idle usage during the night. And comparing idle usage vs idle maintenance, then idle maintenance is less stress for your battery.
This would be a very useful feature that GOS developers should consider implementing.
No matter which super-duper-magical-sophisticated technology the hardware/firmware has to manage battery charging, a lithium-ion/polymer battery will always degrade more quickly if charged to 4.2V/cell (4.35V/cell for LiHV, which the battery in my Pixel appears to be) vs limiting the charge to a lower level. The standard charging range is a design decision by the engineers to maximize per-cycle run time at the cost of total cycle life, which likely makes sense for the average user who wants the battery to last through a full day of heavy use and will only keep the phone for a few years, but it isn't necessarily the best trade-off for all users.
What people are asking for is a way to choose whether they want the default trade-off of longer per-cycle run time with shorter total cycle life, or shorter per-cycle run time with longer total cycle life. A simple toggle to limit charging and switch to idle maintenance mode at 85% like what newer Samsung phones have would extend the lifespan of the battery, and allow us to make good use of the 5+ year support life newer Pixels are promised without needing a battery replacement midway through. It would also allow one to easily switch back to 100% charging in situations where longer per-cycle run time is needed, while making sure a full charge is still close to the original capacity of the battery years down the road.
Finally, I find the insistence that one should not try to be a 'power user' and manually manage charging to be rather disrespectful. The phone is not a magic device that can work around the chemistry of battery degradation. The charge cycle is fundamentally a compromise, and it's a showing of basic respect to give users better control over it.
Agree completely with what navxraxe has posted.
The battery in a Pixel 7 Pro, and a Pixel 8 Pro, which both I have run rooted with locked bootloader for a while (therefore maintaining verified boot, and having the bootloader locked making it so no partitions can be flashed to bypass lockscreen, the only half-sensible way to root), however since compiling GrapheneOS with my own keys I find it much better to flash root onto my phone, use backup apps, then flash an OTA update to remove root, therefore getting the best of both worlds. The only thing I miss, is ACCA, and it's daemon AAC. I'm still trying to get a way to make it run without root permissions, and control it through Termux...
With ACC, called Advanced Charging Controller, you can set the battery % to shut down your phone, and the battery % to stop charging, as well as a bypass to run your phone off power and disconnect your battery from the charger's power path once you reach that %. You can also set a Max mW/s control to control how fast your phone charges in each profile, and a Max Voltage setting (between 4100 and 4300mW) to stop charging at instead if a %.
You can also set a "run script on plug" and "run on boot" settings, that can, for example, be used to force enable fast wireless charging on things other than the Pixel Stand, or enable faster charging via USB corded charging. Also, you can set a Job Scheduler daemon, that will select a profile on boot or on certain time of day, so a different profile can be on all night, slow charging to 60%, then half hour before you get up, it could switch to fast charging to 4.25V, or 80%, both of those are about the same...
The battery in the Pixel is a Lithium Ion High Voltage battery. Others have posted the relevant links to Battery University above, and I have noticed in other devices the downwards trend of batteries to loose capacity when plugged in and at 100% all the time. The internal charge controller is for preventing accidental catastrophic reactions from overcharging, not for giving you more cycles than the design was intended! Also, The internal battery is rated for 500 cycles only! "Wait," you ask, "what if I want to keep my shinny new Pixel 8 Pro for the full 7 years that the support runs for, and I'd rather not replace the battery, 500 cycles doesn't seem like enough, that isn't even two years!!"
Well, your right. My nice, 2 year old Thinkpad X1 Extreme Gen 4, was never used unplugged by it's last owner. Plugged in at home, plugged in at the office. All the time! Guess where it's battery capacity is now? Under 80%! However, my just-sold Pixel 7 Pro I upgraded from, which I ran rooted with locked bootloader for most of UT's time with me, (total almost a year) lost 40 mW of capacity according to analysis while charging! Still had 4960mW out of 5000! I used ACC on it since I first rooted it!
Not everyone has to use such a feature, however I really love how as time goes on, the devs of GrapheneOS are making it so there really isn't as much of a need to root. The recent upgrade to Seedvault is one example. It's D-D backups are just as good, sometimes better than the best root solution out there! Yeah it's not perfect, yes it only looks at and backs up data for recently used apps, and you may need to run it a few times, or disable an app if it is crashing in the background when you get a "backup failed" message, but it does make it so you have the equivalent of a root backup solution, with all the security of a non-rooted GrapheneOS! All we need now are 2 things:
Adblock and tracker blocking! I use this list with 1.5 million lines, it makes the resulting Hosts file @ /system/etc/hosts 56MB in size, when I used to use Adaway to make a larger hosts file. However, without a Magisk Module, /system is not writable because it has 0 bytes of space available. Or at least copy the one that DivestOS uses, since this is ONE thing that they have and GrapheneOS does not!
Secondly, the charging control. It would be a kernel module, or be part of the kernel somehow. I'm sure it is possible, and a belief on the part of the devs (thanks again for all your awesome work!!) Shouldn't be a barrier to them implementing it... If enough people want it, and there's some evidence that it will be useful (as there is), then why not? I know that these batteries are rated for a certain amount of charge cycles, a standard Lion battery in a cell phone is 500. Manufacturers have no reason to raise that, it is another reason to upgrade your device if the battery is not lasting as long! Fits in with this disposable world we live in... I for one would like to keep my perfectly good device around a long time, or when I do sell it, pass it on with a battery in as good of condition is possible!
The Pixel phone runs at too high of a voltage. High voltage will kill a battery quicker. Draining to 0% will do the same. It isn't the full 0% or it would never be chargeable again, and it isn't the full 100% or it would be at risk of catching fire, that's what the charge controller and the engineers who out this all together are concerned with! A battery what will last the specified number if charge cycles, and won't break and not take a charge, or be a safety concern. If however you want your battery to be good for 5X those cycles, so 2500, then charge to 80% and don't go below 20%. That us also not 2500 cycles of the 60% in between 20 and 80, that is 2500 full cycles of 0-100%!
So I think it is clear, this feature is a great one to get! However they are probably also working on more important stuff relating to the core mission of GrapheneOS; security. Perhaps that will take this on later!
The referenced research papers on Battery University are 15-20 years old and where not tested with a BMS and the current used lithium batteries, but solely on smaller lithium cells with different cell voltages 3.3V to 3.7V. Furthermore the references are not directly referenced to the claims in the text. Which research paper proofed the assumption that every 0.1V drop in voltage, will heavily increase the lifespan? Or the assumption that 3.92V is the optimal cell voltage?
I doubt that the discharge into very low voltage areas is even possible with a BMS and normal usage. Normally the cell voltage will stay above 3.2V - even when hitting 0%. At 25% the voltage of a pixel 8 battery is 3.7V according to accubattery. And as long you dont store your device weeks to months at 0%, I dont think you will reach these low voltages of below 2.75V, which could damage your cell.
I don't have any knowledge about charging and cell voltage. The older research paper showed that charging above 4.2V can decrease the life span of a battery because of the build up SEI layer. However the tested lithium cells where likely not the same as currently used in the pixel phones, which peak around 4.4V. I also assume that you cannot charge the phone to the maximum cell voltage, but that the BMS will intervene and your battery - even if it shows 100%, will more likely be charged up to 90-95%.
However I assume that Alphabet introduced the adaptive charging because it will be nevertheless beneficial for the battery health to keep that battery at a lower cell voltage during extensive charging periods e.g. overnight.
Furthermore the temperature will effect your battery life. That's why I try to keep my phone well temperated between 25-30°C. I will not store it in the summer sun, I try to charge it in a colder environment like on tiles and not use it during charging process.
What I wrote are my assumptions, I have no special knowledge in the field - I was just curious how to extend the battery life in general.
collector
I am afraid that article is a bit under complex.
It is true that modern batteries are controlled by a BMS (battery management system). You need that to ensure safe operation of the battery as e.g. Li-ion batteries may explode if charged wrongly.
However, there is no reason to assume that the BMS does anything beyond that, let alone optimization for battery lifetime.
What we can assume is that producers optimize for nice specs. That is usually short charging time (-> high current, high temp) and long battery hours ( -> fully charge). Both is sub optimal when optimizing for battery lifetime.
In fact you can not implement lifetime optimization into the BMS as it is usage dependent:
Therefore battery lifetime optimization control has to be implemented in the OS. In my opinion slow charging to 80-90% should be the default with an option for fast and/or full charging for the user when putting the phone into the charger.
