Unfortunately according to B&N, the Nook Color does not have a user-replaceable battery. From their FAQ (
http://www.barnesandnoble.com/u/Support-NOOK-Color/379003188):
7. Can I replace the battery in my NOOK Color?No. The rechargeable battery in your NOOK Color can only be accessed and replaced by authorized service professionals.
8. Can I buy an extra battery for my NOOK Color?No. Rechargeable batteries for your NOOK Color are not available for sale as an accessory.
9. What if I suspect a problem with my battery?Do not attempt to access or replace the battery. If you suspect a problem with your battery, please contact Customer Service at 1-800-THE-BOOK (1-800-843-2665). Don't worry, your battery is covered by the 1-year manufacturer's warranty or the optional 2-year B&N Protection Plan.
I love how they say not to worry since it's covered under their 1-2 year warranty, but don't mention what to do after this time. Most batteries aren't going to fail in only 2 years, but rather will fail closer to 5+ years. This is a serious design flaw for not allowing the user to replace its battery, esp. if that is the only issue with it.
I still have my original Diamond Rio which was one of the original MP3 players (Back in 1998!) and my only problems have been space issues and connecting to a computer. It came with 32MB of internal storage and a slot for SmartMedia cards for additional external storage (and a few years later someone had developed some firmware which lifted the player's original restriction of the size of SM card that could be used, so I believe that I ended up with either 128MB or 256MB of external storage). Also the original software for connecting the Rio to a computer was developed for Win98, but that same developer that had made that firmware update also created a program that allowed my WinXP PC to connect with it.
Before I go off rambling (I know, too late), I just wanted to state that something in that price-range (I think both the Nook Color and the Rio PMP300 were priced about the same at $200 when they first came out) should be designed to last at least 5 years if not a good decade with battery replacement being something that the user can accomplish themselves and keep it running that long.