I have a weird battery issue in my Redmi Note 4. To begin with, the battery drains very fast but the main issue I'm facing is that at 50% charge, the phone suddenly shuts down with a "0% battery" message. It doesn't turn on until I plug it in, but once I plug it in and the battery percentage shows up, it again says I have 50% (the percentage at which it claimed to be 0% and shut down).
I looked at the battery trends/graph in the settings up and I noticed an exponential drop until 50% and then suddenly a steep spike down to 0% and back to 50% again (its so narrow it was nearly invisible). I'm sorry if you guys don't understand my problem, but is there any solution you recommend? DO you think the battery is not calibrated or do I need to get a replacement battery?