I want to power my Canon T3 from the car. That means getting a 12VDC output to a 7.4VDC. Easy, right?

First, deciding between a custom solution (pcb) and an off-the-shelf solution. Off-the-shelf solutions exist to convert 12VDC to various ranges - among them, 7.5VDC. Perfect.

But then comes a wrinkle: What size plug? I simply cannot find a plug for the DRE-10 battery eliminator. Or, rather, I can't figure out which plug it needs, since nothing will say. Okay, so here's a simpler solution: I can simply disassemble the battery eliminator a bit, and wire/solder to the appropriate terminals directly. That'll do the job, as it's unlikely that any plug - except one made specifically for it - will have the profile to fit inside the camera.

Then a thought: Not only do I want to power my camera, but also my external hard drive. I am getting large SD cards, but not large enough; I need to get two. While one fills up, I'd like to copy data from the other one. My hard drive takes a 12VDC 1.5A line. The aforementioned adapter offers a 12VDC 1.2A output. Good enough? Probably.