This may be a very stupid question as I don’t understand much about how electricity works.
But my music player is usually good for ~20 hours of audio play at a full charge. Last night using it for 6 hours took about 70-80% of the charge, so something was wrong.
I noticed that the insulated wire near my headphone connector had been split open and some copper wire was exposed. Could that be the reason for the abnormally fast battery drain? (I have no idea how - increased resistance or something maybe? The headphones sounded normal though).