Phone battery maintenance - Page 1
Forum section: electronics / general

author: John B
author_rank: Frequent Contributor
timestamp: March 01, 2024, 11:36:31 pm
content: What are the best habits for charging your phone in this day and age? My last phone went through 3 batteries: the first one ended up swelling due to it being left on the charger a lot at 100%, the second was genuine battery but didn't last more than 12-18 months, by the 3rd battery I learned my lesson. I used a non genuine battery which had obviously less capacity, but I took it off the charger once it reached full charge. It has lasted til present day without swelling up.Unlike the old phone, my new one, a Pixel 8, has a glued in battery in a sealed case like most new phones. So I would like to maximise its lifespan. So far I have only needed to slow charge the device up to 80%, which is plenty of capacity to get me through more than 24 hours. These seem like pretty basic conventional tips to maintain a battery.However I read an article which proposes doing what I used to do:https://akc3n.page/posts/battery-management/ie leaving the device fully charged and connected to power. In fact it proposes my current habits are detrimental to the battery.While many of the points seem like they should be correct, ie a modern BMS should be able to manage charging and maintaining of a battery to maximise lifespan, my prior experience tells me otherwise. Also, I would tend to believe manufacturers prioritise battery capacity and charging speed at the expense of longevity. They have an incentive to perform well in immediate reviews and spec comparisons, but have little concern whether the battery goes bad after a couple of years and out of warranty.The article also alludes to something I have wondered, whether the phone is able to operate purely on external power when it's connected, and avoid cycling on the battery to preserve it's life. Again that seems like it would make sense, if it doesn't result in the battery swelling due to a high state of charge.

author: nctnico
author_rank: Super Contributor
timestamp: March 01, 2024, 11:44:59 pm
content: You can buy devices which limit how quick and to what level your phone charges the battery.The article doesn't touch the subject of super fast charging. There seems to be a race going on between manufacturers to make a phone charge as quick as possible. Some even claim 10 minutes. Needless to say this has to be bad for the battery. More sensible manufacturers leave some control to the user. Apple for instance, allows to set the charging speed depending on your habits so the battery life is extended as much as possible.

author: Halcyon
author_rank: Unknown
timestamp: March 02, 2024, 12:13:51 am
content: Quote from: John B on March 01, 2024, 11:36:31 pmIf you're using your phone everyday, keeping it plugged in on the charger overnight won't damage it. Devices like phones don't overcharge lithium cells and some of the more mainstream phones like the Google Pixel, Apple iPhone and Samsung Galaxy phones will adjust their charging behaviour based on your habits (e.g.: If it knows you're not going to be using your phone for the next 8 hours, it'll charge slowly to prolong the life of the battery).Generally speaking, slower charging is better, avoid complete discharges where possible, and avoid excessive temperatures.A good quality phone/battery should easily last you several years, even with almost daily recharging. Even if you keep the phone plugged in almost 100% of the time, the battery pack shouldn't swell under normal conditions.

author: Andy Chee
author_rank: Super Contributor
timestamp: March 02, 2024, 12:16:57 am
content: My iPhone 7 "learns" the power consumption patterns, battery ageing patterns, and charging patterns. So if my ancient phone has this capability, I'm sure newer phones have it too!

author: Bud
author_rank: Super Contributor
timestamp: March 02, 2024, 12:37:39 am
content: I have had an iPhone 5 for 10 years, went trhough 1 replacement battery which is still running, though the phone now is only used as a weather gadget and alarm clock. I used only genuine apple chargers each night going to bed and unplugged in the morning. The original battery lasted 5 years with this charging schedule. And I set battery discharge alarm to 15% and critical alarm to 10%.I think the guy has little idea about what he wrote. Look at what happens to laptop batteries when you mostly use external power. Even if you do not use the battery but leave it in the laptop powered externally, it dies in 2 years.

author: nctnico
author_rank: Super Contributor
timestamp: March 02, 2024, 12:12:02 pm
content: Quote from: Bud on March 02, 2024, 12:37:39 amThat depens entirely on the design (as usual). I have a decade old laptop which I always use with external power. The battery is still good.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 02, 2024, 12:24:20 pm
content: Quote from: nctnico on March 01, 2024, 11:44:59 pmOr just use this free app if your device is supported.https://f-droid.org/en/packages/mattecarra.accapp/

author: nctnico
author_rank: Super Contributor
timestamp: March 02, 2024, 12:25:10 pm
content: Quote from: NiHaoMike on March 02, 2024, 12:24:20 pmBut it requires rooting your phone which is not a good idea. And it may cause you other limitations. Online banking apps are likely not to work on rooted phones as banking apps actively check if your phone is rooted and won't start if a rooted device is detected.

author: John B
author_rank: Frequent Contributor
timestamp: March 02, 2024, 08:54:19 pm
content: On the topic of laptop batteries, my 2012 Macbook Pro's battery died in a similar way to my phone. I always kept it plugged in, and eventually the battery swelled.I've switched to GrapheneOS, and have set things up in what I consider the "proper" way, ie maintaining a locked bootloader, principles of least privileges yada yada. Native solutions to battery management don't seem to exist, but I don't want to root the phone. Maybe a simpler approach would work:For phone charging, I tried charging the phone with my bench PSU in CC mode. I assume the phone has it's own voltage vs current map in the BMS and charging firmware, it was steady at around ~4.7V @ 125mA. It probably calculates the voltage drop at connection vs charging.I wonder if an USB inline buck converter with a soft current limiting circuit to set an adjustable current limit would be a safe approach? Plugged into a USB 2.0 port, the current is limited to 500mA anyways. Dropping the current limit to around 100-200mA would be a good overnight charging rate.Thinking rationally, by the time I've made it, I'm halfway in cost to the price of a new battery. An inline resistor on a cheap USB cable would probably have a similar effect. Still, it might be a handy gadget to make.

author: nctnico
author_rank: Super Contributor
timestamp: March 02, 2024, 10:04:36 pm
content: As noted before: such gadgets already exist

author: John B
author_rank: Frequent Contributor
timestamp: March 03, 2024, 01:25:13 am
content: Quote from: nctnico on March 02, 2024, 10:04:36 pmDo you have a link to a particular device?I'm still tempted to make my own. All I'd need is a simple buck converter like the TPS54231D (3.5V min input voltage, high side MOSFET for low dropout) and everything else I have on the shelves.

author: nctnico
author_rank: Super Contributor
timestamp: March 03, 2024, 01:29:49 am
content: These are the two I know about:https://chargie.org/https://www.liionpower.nl/

author: John B
author_rank: Frequent Contributor
timestamp: March 04, 2024, 01:18:07 am
content: I did some experimentation with simple resistances in series with the 5V line (no data lines connected), and it seems that the phone goes into discrete charging modes/levels. Ie 100mA, 300mA and then 500mA, rather than a variable input current based on input voltage drop.It seemed to work when I tried charging the phone on the bench PSU in CC mode, but I didn't scope the line to see if there were 2 control loops fighting against one another. I'm out of my depth with the USB standard to know if CC charging is a safe way to do so.So in conclusion, the $1 donor cable and 1c resistor is currently the winner in battery charging management.

author: IanB
author_rank: Super Contributor
timestamp: March 04, 2024, 01:44:43 am
content: Quote from: John B on March 01, 2024, 11:36:31 pmHard to say, since it would take many experiments to produce hard data vs. anecdotal evidence.That said, I use the slowest charger available, and charge as infrequently as possible (only charging when the low battery warning appears below 20%). This minimizes the number of charge cycles, and it minimizes the heating of the battery during charging. When I do charge, I let it reach 100% most of the time.After 33 months, my battery health monitor is reporting 98% of nominal capacity (which is sad, I was hoping it would still be 100%). I guess batteries don't last forever.

author: SiliconWizard
author_rank: Super Contributor
timestamp: March 04, 2024, 02:09:06 am
content: "Normal" mobile phone usage makes it rather unlikely to have its battery on an almost full charge for most of its operating time (while this is not uncommon for laptops). Keeping Li-on batteries on full charge for extended periods of time does reduce their lifetime. The actual SOC above which it's detrimental really isn't a fixed value, all depends on the battery itself and other factors. You can find studies with anything from maybe 60% to 80%.And yes, high charging currents (which allow "fast" charging) are also detrimental. So your best bet overall is usually to charge your phone without the fastest charging mode and not leave it on charger all the time as soon as you're staying somewhere with it. Leaving it on charger will not destroy it nor "overcharge" it at all, it's just that the longest it remains over say 80% overall and the shorter its lifetime will be. A few hours per day is not too bad (so, "overnight"), but if you put it on charge, as I mentioned, most of the time and only leave it on battery alone for just a couple hours a days when you're not near a mains plug, that's clearly not ideal.Don't expect your phone battery to last (by that I mean: capacity still above 50% of nominal) for more than about 3-4 years even with a lot of "care" anyway. Those batteries are rated for a few hundreds cycles and that's it. The average is around 500 cycles for 80% residual capacity (which is less than 2 years if you do a full charge every day, which is not uncommon for recent phones and medium users). Beyond that, it depends a lot on the battery, but it will degrade at a faster rate.

author: John B
author_rank: Frequent Contributor
timestamp: March 04, 2024, 02:34:36 am
content: Yep, I won't overthink the situation.However.....I will make the observation that 90-100mA charging current on my phone is only slightly above idle power consumption, resulting in a charge rate of 1% per hour. Hypothetically this would be the best situation when the phone is at home since the power for the phone should be sourced from the external power rather than cycling the battery?Asking for an OCD friend.

author: John B
author_rank: Frequent Contributor
timestamp: February 04, 2025, 10:38:30 pm
content: There may be some merit to the idea of charging a phone just above it's quiescent discharge rate for maintaining system operations.I've just passed a year of use on the phone and have 50 cycles on the battery.The charging current into the phone is right on the edge though, occasionally the phone will stop charging as it probably detects the low input voltage as a fault.

author: tom66
author_rank: Super Contributor
timestamp: February 04, 2025, 10:49:55 pm
content: I want to put a tablet up in my home somewhere for some Home Assistant functions. It'd be nice if I could keep the battery at 50% permanently. That way if I need to take the tablet off its dock it still has enough charge, but the battery shouldn't be cooked remaining like that.Sadly, so far the only thing I can think of that could achieve this, would be some linking the tablet with a wall switch, with the tablet reporting its battery remaining %, and the wall switch turning on and off as necessary. Sounds stupidly clunky and prone to faulting out. I haven't found an Android device with a conservation function like this but it does strike me as something useful for a kiosk-type tablet so maybe there is one, I'd be interested to hear suggestions.Incidentally, my Lenovo work laptop has a battery conservation feature, where the battery floats at 60% - but that's the only device I've found so far that does that. The laptop is about 4 years old, and the Lenovo battery utility reports it is 100% health - whether you believe it or not is up to you, but it does seem to run for a good 4-5 hours, close to the design life. It really does appear to have kept the battery in good condition. Only 50 cycles in total logged over that time, since the laptop is more of a luggable portable machine than an actually useful battery powered machine, the Ryzen 5800H in it makes short use of the battery if you actually push it.

author: John B
author_rank: Frequent Contributor
timestamp: February 04, 2025, 11:41:28 pm
content: From what I remember reading about the concept last year in regards to android, the charging is handled by dedicated firmware/hardware leaving you with little in the way of userspace control.My thoughts were fairly similar though in terms of making your own connect/disconnect circuit for the tablet.A simple battery level value is more easily accessible. Home assistant may have some integrated API for that already, but alternatively you could run a python MQTT script on the tablet to report the battery level at regular intervals. An ESP32 could handle a connect/disconnect circuit and communicate with HA via MQTT.Python library compatibility on Android is likely a sticking point however. KDE connect on the tablet is also another option as it reports many things about the device including the battery. That will require KDE connect on another network device, then investigating their API.I didn't need to develop the idea any further though, so that's as far as my ideas got.

author: tom66
author_rank: Super Contributor
timestamp: February 05, 2025, 09:32:02 am
content: The nice thing is you can get the tablet battery via Chrome, so if the tablet is just accessing the web interface, it should work that way; or alternatively, it can be linked in with the HASS app, which then will report the battery level.But the issue is as you note, what do you then do with that information, because regulating the charge level requires some way to stop the tablet charging when the USB is connected for power, and I don't think that's possible on most Android devices without modding something.This looks promising:https://github.com/VR-25/acc