Samsung Galaxy Note 9 Possible Battery Problem

BuyoTheCat on 21/08/2020 - 19:56
Last edited 14/09/2020 - 18:12

Update 14/09:
They put in 3 more other batteries and I asked them to get batteries from a different supplier.
FInally, it seems to be working fine. (been using for 3 days.
End result, a bad batch of batteries (just my luck. almost ready to give up)

I have a Note 9 that I got 2nd hand SM-N960UI (a snapdragon model from US)

Been working well for about 2 months, then it will randomly restart. Hmm…my previous similar experiance with a Note4 restarting, is a rooted battery. performed the samsung device diagnosis and it said battery rooted. Samsung stores are closed in VIC so I went to a nearby phone repair place and got them to replace the battery for $99.

Here is what it is doing now:

charged it up works well till battery gets to 50%.
goes from 50% to 40% within 10 min and then shuts down
Put it on charge and the battery charges from 0%. So the battery discharges from 40% - 0%.
charged up 12pm its 100% and it drops to 40% by 7pm. a bit quicker then i expected.
device diagnosis says battery ok.

I have only been using for 2 days at first I was thinking that I thought that i might need to let the battery go through a few cycles. It seems unlikely now.

My question is: how likely it is that the battery that was replaced is faulty. I do not want to hassle the shop unnecessarily

Please help.

Update: I have discharged and charged it up to 100% then run MX player till it dies.
The first few times I charged it while off, till the display says 100%. and leave it on the charger for another 30 min.
Powered on, it shows 80% (78% another time)
I turn it off and charged it again. (another time I left it on and continued charging it till 100%

I played videos on MX pro till it goes dead. which it does at around 69. (i set the time and check it every 15 min, recording the %
7pm 100%
8:38 69
8:51 already powered off

Mobile Mobile Phone Samsung Android

Comments

  • Melb69 on 21/08/2020 - 20:11

    What screen time are you getting on the new battery. Just as I was checking my Note10 plus I have managed 9hrs 36mins and is sitting on 12%. I know it may drop off the cliff shortly. Thats having the phone on from 8am to 8pm.

    • BuyoTheCat on 21/08/2020 - 20:37

      Not 9 hours for sure. Perhaps 4-5 hrs? I wasnt sure how it was suppose to run with a new battery. It seems to last normally (feels a little less than normal) till it hits 60ish% then it discharges really quickly

      • Melb69 on 21/08/2020 - 22:40

        Well just after I finished typing my comment the phone died. At 60% definitely something not right there. When you first charged it was the battery cool. Slow sharging not fast charging.

  • perhaps on 21/08/2020 - 20:31

    Also check what's running in the background

    • BuyoTheCat on 21/08/2020 - 20:44

      is there anything that can cause it to go from 40% to 0%?

      I have not installed anything new

      • perhaps on 21/08/2020 - 21:11

        Have a go running it in Safe Mode and see if that helps. I'm not too sure what could be causing the drop, could it be that the battery is not calibrated properly? As in the 40% could actually be close to zero but its misreported.

        • BuyoTheCat on 21/08/2020 - 22:12

          Thanks for bring up battery calibration. I looked into that and I am going to try a few things.

  • burningrage on 21/08/2020 - 22:02

    From experience, the phone actually misreads the actual voltage relative to the % of the battery.

    Having the Notes family since Note 3 even to my Note 8, I can be confident to say the battery is faulty if what you said is true that the battery has been replaced with a new one but without having it done at official Samsung store, it is a bit hard to claim warranty.

    After about 2.5 years and closing to 3 now, my previous Note 8 would die when the battery was at 20%, but if you use a battery analyzer it will say the voltage is really weak like 3.3v or 3.4v. Having a new battery helped restore my phone but I am mighty tempted with Note 20 but that's another story to tell.

    And another thing with device diagnosis. To this very day, I have never found an app that can honestly read the true state of battery capacity of a mobile phone. I do expect to see one but never found one that was truthful. THey would always say the battery is healthy and the capacity is as per what the manufacturer capacity is EVEN if the true capacity would have been a lot lower.

    This is unlike a EV car battery that can read true battery capacity and I can see it dropped down to 80% after 4-5 years but alas, nothing like that for a mobile phone battery.

    So I believe you have been given a faulty battery. Happy to be corrected though.

    • BuyoTheCat on 21/08/2020 - 22:11

      @perhaps (the previous person who replied) said something about calibration. So I am going to try that. my googlefu brought up a few things.
      even dialing *#0228# I am going to give it a try. I was going to go to Samsung but shops are closed in VIC

      I am going to charge it to 100% then leave it there for a while, then run it down totally. try that for a few times.

      • Melb69 on 21/08/2020 - 22:42

        Worth a try doing these things.

      • burningrage on 21/08/2020 - 23:04

        For now, that's the best thing you can do.

        Good luck.

  • fantoo on 22/08/2020 - 00:29

    It can be the issue with logic board

    • BuyoTheCat on 14/09/2020 - 18:14

      I gave it to them to check the logic board and it was checked ok. so I asked them to put another battery from a different source and it seems to be fine now.

      I am not sure what kind of diagnostic tools they use for checking the board.

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