I was doing tons of research into these things a couple months back. I actually have two battery trays under my hood, but right now I'm only using the stocker. We constructed the additional battery tray from angle iron. Anyways, I never did finish the project. So I just ended up with one optima yellow top battery. But if I do finish the project I'll add another yellow top. Anyways, you really need a better battery that's part of your problem. Since, your running a computer I'd recommend a deep cycle battery such as a yellowtop optima. My car battery would normally last 15 minutes before it was dead, with my high power sound system. The optima will last over a hour and probably more, and still be able to crank the engine.
When you do hook this thing up, use the biggest wire you can find, and keep the leads kinda short if possible.
I would connect to it to an accessory wire inside the vehicle, there's losts of places to find them. You could even tap into the cigarette lighter or if you wanted you could tap into the ignition wire off the key.
Bennett
