Why does my new 3ds xl turn off after going into sleep?

My New Nintendo 3DS XL repeatedly turns off whenever I try to enter sleep mode by closing the lid on the screens. It also turns off after exiting from the settings menu, and after any attempts at a system update.

I suspect that it's an issue with a faulty battery, but I'd like some confirmation before I go and pickup a new battery. I bought the unit used, and have only been playing it for about an hour before I noticed the issue.