Note 4 battery draining and refusing to stay switched on

[Brockswood]

Hi folks

Complete noob out of his depth here. I have just been given a Note 4 to try out Android - I am a little late to the party, you might say - and it appears to have a critical problem of some sort. It's in as-new condition externally and behind door number 1, having been sitting in a drawer for at least a year after a relative used it then upgraded.

On receipt, the phone was functioning perfectly. However on my 2 1/2 hour drive home, the battery drained from 100% to 47%. The phone was on, but not being used. It is currently draining fully in about 90 minutes of use. It also jumps down, say from 70% to 50% battery.

As if that weren't enough fun, it also shuts itself down a lot, ostensibly at random but sometimes I've noticed it's when I am asking the phone to switch between tasks. Once it's done this, it will absolutely not turn on again unless it's plugged in to a charger.

So far I have tried:

Battery calibration
Turning off all apps that might be draining power and setting all apps to Always Save Power
Turning off Fast Charging
Turning off location services, bluetooth, and WiFi
Bought a new, official Samsung battery and tried that out in the phone
Booted into recovery mode and wiped the cache partition
Static clearance from handset with battery out
Checked this forum and several others to see if this issue has been answered already

And needless to say none of that has worked! If anyone can suggest further steps I would be very grateful. I did take it to a professional, who told me it was the "charger chip" - does this mean the PMIC? If so, can I change that myself without a bunch of proprietary tools? I would rather repair the phone myself if possible, to save money, and learn about this curious new Droidy world I find myself in.

Thank you in advance.

 

[Mooncatt]

I'm still leaning towards a battery issue. I know you bought a new one, but I'm guessing it was sitting on a warehouse shelf for a long time (that is an old phone, so little demand for producing fresh batteries). It is possible for a Li-ion battery to go bad while sitting on the shelf because they will self discharge over time. When you got the new battery, did it have a very low charge like under 20%? If so, chances are, it's a dud.

 

[Brockswood]

Hi, thank you for your reply. When I bought the new battery, it said 61%. Then the phone turned itself off.

When I took it into the store, they did try another battery off the shelf then and there - phone said there was plenty of charge in it, but promptly turned itself off. So it may be as you say and their entire batch of batteries is bad.