So I brushed off the dust off my K1 (stopped using it after I got my s8+) which I hardly used anyway. I fully charged it, and start using it. But I noticed the battery is wacky. I watch one 20 minute anime or any video and it drops 10%. Is this normal? I have the screen brightness pretty low to. After that I did a fresh factory wipe and its still doing it. Do you think I have a bad battery or is this normal performance for the tablet?