I think the Moto X has a platform-wide problem with low battery...
Cross-posting from AC.
So - I've had three Moto Xes - my DE, a replacement DE and now my daughter's unlocked moto-maker.
All three have had the same annoying low battery bug. When battery life drops below 15%, it can suddenly show 1% battery remaining - and stay at 1% indicated for a LONG time.
I opened a case on it with Motorola, they sent me a loaner DE and I sent my original DE in for repair. They sent my original DE back to me a week or so later, after having replaced everything to do with the charger and battery. It still exhibits the same behavior - and as I said, my daughter's brand new motomaker X and also the loaner DE ALL exhibit this behavior.
I'm guessing that the excellent battery life means that most don't see this - or they do as Brian Klug suggests, and they just strategically charge it whenever they're by an outlet/charger.
I tend to use the crap out of my X so I'll hit the 15% mark a few days a week - I stream Play music on high quality and have two days a week where I have 16 hour days.
Anyway - the point being, statistics say it's highly improbable that my three references all suffer from some low-percentage issue out there. Instead, it suggests that there's a huge platform issue. My guess is that there's a problem detecting low voltage on the battery, either via a firmware bug or worse a hardware bug.
Here's hoping it's software. How many others have seen this? It's pretty incredibly annoying when you're at the end of a long day, it's at 20% when you get to a bar and then pull it from your pocket and it reads 1% and you don't have any idea how long it will actually last.
A guy over on AC with a verizon Moto X is experiencing the same issue. I just don't see this as being a random, small sample issue.