Weird Charge (iPod Touch 5)

Hello, I recently got the new iPod but I've noticed something strange about it. I use the dead-to-full charging method (Use it till it's dead, charge it up to full) and I plugged it in about ten minutes ago after it going dead. Within ten minutes it gained 45% charge. This kinda scares me because the main reason I got a new iPod was for a better battery than my older second gen. I'm wondering if this is normal and it's supposed to be gaining this much charge so suddenly?