It's no secret that I'm planning on getting the RED onto a helmet for some skydiving. I've been laying the groundwork for a while [getting a camera owner who's willing, getting a talented enough camera flyer, securing lenses, etc.] and it's come time for me to build a battery solution for the camera.
As it stands, the combination of a RED V-mount plate and a RED BRICK would add several pounds and a lot of volume to a helmet-mounted camera system. It just won't cut it.
Here are a few pictures of the style helmet we'll be using with the camera:
It's a big helmet, but the RED will take up the entire top. It's the only thing I want outside the helmet. Extra stuff outside the helmet raises the CG of the helmet [neck strain during deployment] and adds snag points [suspension lines + snag points = bad].
My plan is to build a battery that can fit on the inside of the helmet in the space above the jumper's forehead. I was considering building my own batteries from scratch by either putting cells together or making some brick of disposable batteries, but a little thinking dumped me on airsoft gun batteries.
They come in several varieties including 12V. They come in ranges from about 600mAh to 4,200mAh.
This is a 1,500mAh 12v battery that would fit nicely into that forehead space. That's an 18WH battery [vs. the RED BRICK's 140]. A 4,200mAh battery would be 50.4WH.
They use this little connector for power:
I have one LEMO connector for the power left over from the four I originally got from RED [somebody stole the other three from my car, but that's another story...]. I'm thinking about making a very short "dongle" that I can plug onto the back of the camera that will go from the LEMO to this little plastic connector. That way I could use a softer, more flexible and cheaper cable to run from outside the helmet to inside.
Lighter cable means less flapping, though it does increase the chances of failure. I dig this connecter because it's cheap, easy to find and replace, easy to throw together and tiny. An XLR [even a mini-XLR] wouldn't cut it. If the camera comes off of the helmet in freefall or on deployment, I need this cable to fail easily... and that plastic connector will be the weakest link I can keep in the system.
So, question time. Most of these are to RED.
1. How should I wire the "dongle"? As we all know, there are two positive and two neutral pins in the LEMO. Should I make a short run of a four-core power cable from the LEMO and just solder them to the single positive and neutral leads on the airsoft battery connector? Is there any kind of even current split between those pins in the LEMO, or will the wonders of copper figure it out for me?
2. Will the camera even run on a 1,500mAh [18WH] battery? Airsoft batteries tend to be capable of supporting pretty impressive amperage draws... think it'd work? What does the camera draw sans LCD and EVF? Just the camera recording to CF.
3. Is there something I'm missing? We're just talking copper here...