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S20 Ultra battery and charging problem after Android 12 update

(Topic created on: 20-01-2022 08:23 AM)

I have  problem with the battery after updating to android 12. The battery drains very fast. However, I also have a problem with super fast charging - it is not super fast anymore. I have 40% of the battery, connect it to the charger and it shows that it takes 45 minutes to fully charge. After 50 minutes, I check, and there 67% and 25 minutes until fully charged. After another 30 minutes, the battery is 90% charged. My S20 ultra is slower overall, discharges faster and charges much slower.

I did cache partition. Didnt help at all.

First Poster

Just because the phone reports that it is Ultra Fast Charging, doesn't mean that it actually is. You need to analyze the charging data. I suggest an advanced Battery Monitor, such as "3C Toolbox" or "3C Battery Monitor". What I like about this/these apps (3C Toolbox is a full system monitor, 3C Battery Monitor is just the battery monitor component), is that they provide charts showing current (mA), voltage (mV) and power (mW). The voltage parameter is the current battery voltage, not the charger voltage. Note that the app cannot read charger output voltage, and therefore, the current mA will be the overall drain at the battery, while power seems ro work to show what the charger is putting out with my Snapdragon phone, at least.

So you will want to look at power most importantly. You can tap on the graphs until it shows the "battery usage (mW)", and then slide along to look at it.

I would set up 3C, grant all necessary permissions, install any companion app it needs, configure the battery monitor for short measurement intervals. You may also want to enable the "system recorder" in 3C Toolbox (and enable more detailed data collection in the settings), which will show you individualized battery usage over time, and catch some of the apps that try to hide themselves from battery monitoring (as the battery monitor also monitors apps, but using the system default, rather than running as a foreground service to manually collect data). 

Do a charge from a low battery percentage to full, and try not to use the phone much during that time so you can get a clear idea of current (base draw is only like 100mA in sleep mode (closer to 50mA in power save mode), so that will be negligible. That will help you figure out what's causing the slow charging. It will also record battery temperature: see if possibly the charge is slowing specifically in response to the battery reaching a certain temperature. If that is the case, it used to be that once the battery hit a certain temperature threshold, charging would scale back to the equivalent of fast charging or slower, and even once it cooled, it would stay at that rate. I used to have to plug and unplug the phone constantly to get proper charging- I thought that was fixed though. If your battery is quickly heating, it may be damaged or overcycled. You should be able to see how many cycles (0%-100%) the battery has underwent from within 3C (I think), is not designed for more than something like 1,500 cycles total. Another thing is that if you charge from say, 18%-55%, that is basically a cycle. That is why they say to charge the phone fully (or past 85% at minimum) once you plug it in for best battery lifespan. With any Lithium based battery, you also never want to let it fully discharge (which you actually really CAN NOT do with Samsung, or most major manufacturer's, phones, because they power down and display 0% when they actually still have around 15% battery capacity remaining (specifically to protect the battery from conplete drain, which causes severe cell damage, supposedly also for tracking purposes, hense why phones no longer have removable batteries). Still, it's actually best for battery health to keep the phone above 50% capacity (or above 35%), conduct charging in single sessions (i.e. 55%-100%; NOT 55%-75%; down to 70%; charge 70%-100%), not use the phone while charging (as to prevent overheating cause by the current draw combined with input, and because the battery functions best when either charging or discharging, not both), AND to remove the charger after the phone hits 100%. Keeping it on charge for long periods after it hits 100% is one of the worst things you can do to lower battery lifespan.

The average person, who doesn't let their phone die and stay dead for days, remembers not to keep the phone on the carger all the time, and doesn't constantly plug and unplug the phone, will get about 2 years of daily use out of the phone before the battery performance starts to significantly degrade to a noticable level. A user who practices bad charging habits might only get about a year before their phone loses 30% or more of its original capacity. After about 5 years of daily use, the battery will likely have about 40%-50% of its original capacity- although new OS's designed for faster, more efficient phones with better batteries that have been auto-updated to the old phone, will make that 50% feel like 25%. Past 5 years, most batteries will need replacing.