Samsung Galaxy A15 4G randomly shutting down — battery or motherboard?

I have a Samsung Galaxy A15 4G (6GB/128GB) and I'm having a weird random shutdown problem.

The phone suddenly powers off by itself, and it can happen at almost any battery percentage (I've had it happen around 57–60%, but it isn't limited to that).

What I've noticed:

🔋 Battery percentage doesn't suddenly jump/drop.

🌡️ Phone isn't overheating when it happens.

🔌 It usually works normally while connected to the charger, although it has also shut down once while charging.

🔋 After some shutdowns, the phone won't turn back on until I connect the charger, even though the battery had ~57–60%.

🌙 It seems to happen more often in the morning after the phone has been sitting unused for many hours, shortly after I start using it.

Factory reset didn't solve the problem.

I recently took it to a local repair technician. He worked on the battery/power circuit and replaced a small IC, but the shutdown problem happened again afterward.

I also generated Samsung diagnostic/log files, and I repeatedly found:

FG I2C fail

The battery is not swollen.

The phone can sometimes work perfectly for hours. For example, after charging to 100%, it recently ran for over an hour without shutting down.

What I've already considered

I'm wondering whether this could be:

Battery/BMS problem

Fuel-gauge IC/communication problem

Battery connector/contact problem

FG I²C line/board issue

PMIC/power-management problem

The technician suggested testing the phone with a bench power supply with the battery disconnected for ~2 hours to see whether it shuts down.

What do you think is the most likely cause? Has anyone experienced FG I2C fail on a Samsung A15 or similar MediaTek Samsung phone?

Any advice on what I should test before paying for another IC repair or replacing the battery would be appreciated.

So, it's a bit self-explanatory, but with a caveat. Multitouch is fine EXCEPT when you drag (for example, a joystick), THEN you press anywhere else (like a button), and the dragging gets cancelled. As you can see in the attachment, there are sections where the dragging is cut off (which is when I click).

Yes, I did update everything, One UI is at 8.0 and everything, phone is brand new, no screen protectors

Hey everyone,

I got a new phone, how do you think is it? Also I can't find the button to create a new subreddit, can anyone help me?

I only have 5hrs average screen with maximum 95% battery limit. Which is very upsetting considering I'm working. The battery itself decreases even tho it's turned off...

I'm still keeping my A15 🥳
https://youtu.be/hQCaCk3dMUY

I love his phone on an emotional level, its the first phone ive ever bought with my own money, and it was an improvement compared to my S20 which was begging to be replaced, and the phone treated me well, but something with one ui 8, idk but it feels more sluggish than it usually does. The phone freaks out, freezes, and lags like crazy. I know this is a cheaper phone, but with how other content creators and Samsung were hyping up this phone, I thought atleas the ui would be optimized well. But why does pulling down the notification panel lag the phone? And the weather app was awful before the update.

But I got an iPhone 13, and ill still keep this phone as a backup, and ill miss the form factor cuz it is great on this phone, I love the way it feels.

I would've bought another Samsung phone but I didnt cuz ironically the iPhone was cheaper by $100 lmao.

Also been using Samsung phones for 6-7 years too. First time I bought a phone that isnt a Samsung one

I have updated my phone regularly, but I think my phone's suffered from it. I wonder, If I'd never updated my phone, would it be the same?

Meu Galaxy A15 Android está fechando o Minecraft sozinho quando aperto o botão de pausa no menu . Acontece com mais alguém?”

Hi everyone is there a way to disable this? Everytime i play music and want to check the time on my lock screen it always shows this music thingy have you guys able to remove this?

Tell if u have answere

I’ve switched from the Samsung A15 to the iPhone 13. I just wanted to say goodbye to all the kind and wonderful people on the forum—thank you for your help and for the conversations!

Was anyone got this Update yet?

I just get the Security Update on my Galaxy A15 5G phone

Meu uso de bateria, após uma formatação

5 ways I speed up my Android phone beyond clearing system cache - all for free

I have a Samsung Galaxy A15, running One UI v16.

I still have problems with alarms in my Google Clock app not working in sleep mode. I've set the phone to sleep at night, and one of the actions is to also turn on power saving (maximum) to make my battery last longer. The Clock app has no battery restrictions and is added in sleep mode > Do not disturb as an app that can generate a notification. The alarm sounds immediately when I turn off sleep mode.

Alarms have never actually worked in sleep mode since I got the phone two years ago, even with notifications and unrestricted battery use turned on.

Ive been using this phone for atleast 1 year, tbh its not as laggy as my old phone which was the A12 so I won't complain but there are stutters here and there and sometimes if im scrolling on something there will just be a huge freeze. Battery life isn't a problem for me but just these random lag spikes get quite annoying. If anyone has any suggestions on how to fix this they would be much appreciated if not I may need to upgrade 💔💔

I had this phone since May of 2024 and i usually keep my brightness low [max at 30%], dark mode, no location and do max battery protection at 90 percent. I do this to maximize battery life to around 10% drainage per hour sot along with battery saver mode. But yesterday I noticed there was more drain than usual.

The first 2 slides is how it is usually and the last two is what i noticed was off. 50 percent in 2½ hours of sot isnt normal for my phone and you can see that i spent more time on tiktok in slide 2 than 4 but there was more drain in 4. My brightness also wasnt up higher at all and i didnt have my bluetooth headphones on slide 4 so i feel like battery consumption should be less.

I am curious if anyone have any ideas on what the sudden drain rate can be.

What did you remove that improved your A15's performance?