I have a 2-3 year old iPod 2g 4.2.1. I sleep at around 10:30 and wake up at about 6:20. When I sleep I usually have 5-20% battery left. Do you think it's "healthy" for my iPod to charge overnight? I also charge for a littl (sometimes)e at around 5pm if my battery is low to boost it up to around 50-60%