I am need of powering a DSLR for extended periods outdoors in the winter, so portability is critical.
I thought about an off-the-shelf inverter along with the factory AC power supply, but this is somewhat more money than I wanted to spend. And, the inverter and AC power supply are huge which sort of kills the portability.
I would like to utilize different, large capacity, batteries anywhere from a 12v motorcycle battery to just a bunch of stacked AA cells that I can throw under a coat sometimes. I am not sure how to regulate these sources for the camera.
The camera uses 7.4v batteries that I've seen variants ranging from 1900-2500mA, but I don't know how many amps the camera actually draws or requires for normal operation.
Is this really just a matter of slapping together an LM317 with a proper resistor for 7.4v and not worry about things like current draw from the camera? If not, what exactly do I need, and are there any kits known to exist for this purpose?