Kobo Libra H20 Rapid Battery Drain

My Kobo Libra H20 has been having huge drops in battery for what seems like no reason. I'll charge it up fully, use it for a day or two without issue, and then I'll wake it up and it'll be at 19% battery after having been at 95% when I was using it a few hours before.

I've done a factory reset, I've converted all my ePubs to Mobi and then back to ePub (I actually didn't sideload anything for a while after the factory reset and it still happened), I've turned off wifi - None of which has helped. I'm on the latesy update, as well. Does anyone have any idea what is happening or is this thing just borked?