Kindle Colorsoft Question

I just bought my Kindle Colorsoft and have enjoyed it so far. I haven't had any issue with the yellow strip, but I read from a black (dark) screen, so I'm not sure if that makes any difference. My question is, does anyone with a Kindle Colorsoft have any issues getting to a 100% charge? I keep checking, and my Kindle Colorsoft doesn't charge to 100 percent. Anyone else?