Finally, it's done. Actually, it didn't take anywhere near as long as I thought it would to put it together.
1 12 volt 75AH marine deep cycle battery
1 marine battery storage case
1 Radio Shack red rocker switch
1 Radio Shack cigarette lighter with built-in 10A fuse
20 10A fuses!!!!!
The wiring was pretty easy. Postive from the cigarette jack to the switch, then on to the battery, and the negative right to the battery. I drilled holes in the marine battery case for the switch and cigarette jack using a drill for the initial holes, and then a rotor-tool to widen the holes according to the required diameter of each switch/jack. Installation of those was easy as the switch had a rear screw for mounting, and the cigarette jack had a nice clip-on system which helped affix it to the case. I taped the excess wires in the box into tight loops to keep the insides relativel tidy. I went through quite a few few fuses as my multimeter blew out, and had no way to test the polarity, but this was expected as I am a real divvy when it comes to electrical stuff. Anyway, finally I had it rigged up and tested it on an old mobile cell-phone charger. Satisfied that this was working okay, I plugged in the Meade 12volt to 18 volt converter, and it seemed to work fine. Then, the big moment... Dragged out the scope and plugged it in. Turned it on, fine. Conducted a few GOTOs, fine! Actually I am no longer hearing the oscillation in my GOTO motors, so I think this will kill my GOTO issues. So, mission successful, I think!
Next week will be the real test, as I'll take it out to the field for the first time. Wish me luck...