Same problem here. I have had the Roku Ultra for less than a month and the battery on the remote is completely drained.
From what I've found by looking at the forum: seems to be a VERY common issue. Some issues are that if you move the remote too much, since it can be used as a game controller, it apparently drains the battery. Not sure why it would do that if you're NOT playing a game, seems like it would be a simple firmware update to make it so that it doesn't use motion sensing if you're not playing a game.
Others have suggested it might be because you're using the headphones. Ok, I get that.
For me, I have used it ONLY as a remote, picking it up to change the channel, or navigate the menu, and putting it back down. If that's draining the battery, I don't know what to tell you. How else are we supposed to use a remote?
I also found out that new members cannot easily send PMs to Roku employees, supposedly some sort of anti-spam measure. Ok, but then how in the heck are we supposed to get help? Why can't we have a button or online form to submit a ticket about our problem? Why isn't there a way on the Roku itself to send a support ticket, thereby cutting down on spam?
Was super happy with the Roku until this remote draining issue. Been using my phone for the past few days as a remote because I can't find any method to get customer service. How are customers the priority if we're blocked from all methods (commonly used in almost every other product I've had in the past) of communication? I mean seriously?