Well this is a full spectrum camera so you would need to block all visible light with a ir filter unless ur in a location that is pitch black, but this camera has a fixed focal length and no optical zoom just digital, so I would not recommend this cam for anything that may be at a distance, maybe the Bell and Howell DNV16HDZ-BKFull 1080p HD 16MP Infrared Night might be better..... it has 10x optical zoom but is a ir cam not full spectrum. Both would need ir filter tho if u want to capture pure ir image only with no visible light. The bell uses 37mm filter this one is a 34mm.
It can be plugged in via USB as a webcam, for file transfer, or printing, but there's no way to use it in "normal" camera mode without the battery. USB is the only external power source - and works without the battery - but only as an external webcam connected to a computer.
you can charge and record I've done it with mine. and as for memory it can hold up to 64gb sd card so i think it can record up to like 6 hours unles you add a second micro sd card . also if you have a computer it will record to the computer instead provided the drivers install and it works like a web cam so it could record all night.
I cant speak for the other camera but I love this one. For the price it is amazing. Only shoots about 10 to 15 feet clearly with just the IR so added an IR light to it. Picture is awesome and you can take stills without interrupting you video. Also has a full spectrum feature. Note that this camera however is really small. It fits into the palm of my hand. Was delivered ahead of time as well