S21 overheating and slow wireless charging

[mmtech]

My phone reaches around 40 degree within 15 min of phone use.

Same with Samsung wireless charger. After 15 min of wireless charging. Temp is 40 degrees and then extremely slow charging. It shows 2 hours 40 min for full charges but actually charges full in 5 hours. Very very bad experience.

[Joeeye]

So a 30C cpu temp sounds about right even idle. These chips have no active cooling so how do you expect them to keep cool?

[Babishko]

I don't monitor my phones temperature any more mmtech as I don't have to as it is as cool as a cucumber in it's case in normal use. When on a combined photo and video shoot the phone gets a little warm but nothing more. It really is great to get to the point when you don't feel any excess heat in the phone and can trust it totally when really giving the camera a stiff lengthy test. I hope your phone can cool down to the point where you can just enjoy using it again mmtech but I appreciate this will take time for you as it did for me. All the best in your quest for the cool running phone you deserve my friend. 👍👍

[mmtech]

That's right but as soon as you pickup and start doing anything it reaches 35 C. If you have video call it reaches 40 C

My main problem is wireless charging which slows down to extremely low speed when it sees phone temp above 35 C. Phone still shows fast wireless charging and 2 hour 40 minutes remaining but actually it takes more than 5 hours to full charge due to phone temp being high.

Samsung doesn't do any testing before releasing. Here room temp is 25C imagine countries where room temp goes to 45C and same exynos processor is being sold. Its such a bad planning and strategy.

[mmtech]

I am waiting for 1st software update hoping that will fix the issue.

[Joeeye]

You mention Exynos as if it's some exclusivity. All of the modern SoCs (Yes that includes Snapdragon) heat up and in fact SD variants can and do get hotter. I know its so simple to go Exynos bashing like the good little soldier but what people don't seem to understand is simply CPUs and thermals. They rise up to near 3GHz and sit in a confined case with no active cooling, no fans (most anyway) and you somehow think they'll maintain a frosty what 10C? Where do you expect that heat to go? Every electronic device produces heat and these phones cram a lot of it in. PCs literally crash in hot countries all the time and they get fans. You think your mobile is immune to this? When a device gets hot you either lay off it or try to shade/cool it, it's pretty simple logic.

[mmtech]

I have moto g7 play and had very good experience. Its temp stays at 25 c in ideal and reaches maximum till 30 c. That's it. Thought android improved over years but samsung still the same. Always power hungry and battery overheating.

[mmtech]

This isbspecific to damsung phones. I have used moto as well as Google pixel. Also iPhone for years. None of them gets this much hot like Samsung. I am not blaming snapdragon or exynos. Its samsung which is the problem.

[Joeeye]

You ran the latest flagships of these brand phones? Moto tend not to use high end hardware same with Google, so they're unlikely to get this hot. As someone who follows tech and mobiles very closely, trust me when I tell you, the heat on these phones isn't a Samsung exclusive. You take any Xiaomi, Huawei, Oppo or Oneplus and I guarantee you all these devices can and will heat up just as much. Some try to reduce the heat like Asus ROG phones with active cooling but typical mainstream phones will just get hot. It's the nature of high end devices, more powerful SoC, more energy usage, more heat. The price you pay for cutting edge tech.

[Joeeye]

Why bother with a Samsung high end phone then if you had such a great experience with your moto g7 play?

If Samsung phones are always power hungry and battery overheating its news to me seeing as I've bought about 6 of their flagship phones over the years and haven't experienced a single one of those issues.

[mmtech]

I wanted to return back to Samsung to see if they have improved in power efficiency as there previous UI was power hungry. But it looks like its still the same. They run so many unwanted services in background which doesn't show up in battery and device care so no one knows what is draining battery.

Below is the snapshot with no background apps running as i have limited background usage for all apps apart from google.

Overnight battery drain in DND mode -  4%(Moto G7 Play)   12%(Samsung S21)

Day time Battery Drain in idle - 1% in 1 hour(Moto G7 Play)   1% in 20 min(Samsung S21)

Temp in idle - 26C(Moto G7 Play)  30C(Samsung S21)

Normal Browsing - 28C(Moto G7 Play)    35C(Samsung S21)

Gaming - 33C(Moto G7 Play)      39C(Samsung S21)

Samsung support suggested me to charge phone in safe mode to know whether there are any apps causing issue or its faulty phone. 

Wireless Fast charging - Its showing 2 hours 40 min to full. if it charges in this time then fine but if it takes 4-5 hours still in safe mode then serious issue and have to report to Samsung for further troubleshooting.

Will post the results in some time.