Seems to me if #1 is an issue, then one could/should remember to charge the device at night so it’s ready to go the next day in class. You do it with your cell phone, don’t you?
The Clip+ has a low quality mic. For recording you should get a decent recorder lthat has better mic(s) and a mic jack with a choice of recording bitrates that can record in mp3 or wma. I suggest you look at the Olympus ws700m,but if you want something cheaper, consider the Olympus VN8100PC or VN8000PC. The VN8100PC and VN8000PC are just mono and have no card slot.