What is best video camera in terms of quality and battery?

Low end dSLRs are designed to capture still images. Video is a secondary convenience feature. If you understand the overheating/auto shut down and long cool off, segment length limitation and several other things, and still insist on a dSLR, then you need one that is designed to capture video - like a CANON EOS Ciname Cam (C100, C300, C500), Blackmagic Design Cinema cam, Sony NEX-VG series or NEX-EA50UH and several others. Now that you know about some of the known, published, problems with low end dSLRs and video - all this and more is in the manual - download them form the camera manufacturer), you don't get to complain about them when they happen. And don't forget video lighting, audio issues, steadying equipment and more. Sine we're here, we don't know if your computer is equipped to deal with editing high definition video - CPU, RAM, available hard drive space and the editing application all contribute there, too... For battery life, get another batter from the camera manufacturer - SInce the dSLR with overheat and shutdown wee before the battery is used up, you really don't need to worry about this. If you insist going this route, the easiest is to get 2-3 of the same camera. While one is in use, the others are cooling down. A camcorder like something from the Canon HF R or HF M series is more appropriate. No over heating problems, mic jack, and designed to capture video. Good luck.