I wanted a way to power my CGEM in the field when there was no AC power, so I decided to build a battery pack. Looking at the Celestron website, it said that the CGEM only needed about 1.5 amps (12v) max. So, my mother had this handheld vac that she didn't want. We (my dad and I) decided to build the battery pack off that. (pic 1). Looking online, it appeared that the vac battery was 2amps (ok, 25 air watts, which is something like 25.04 watts, which is something like 2.09amps [12v] ). So, we took a spare plug that fit the mount off of something different out of my dad's electrical junk. After some cutting and soldering, (pics 2, 3) we had a small power pack. (pic 4). We did some testing against running off of normal house current (with converter): I would slew the mount to a point on the RA axis, time it, and do the same with the power pack, and timed it. The slew speeds were the same (ok, within .01 sec. I'll call that the same). We then did another test: we measured voltage of the battery, then did almost 5 minutes of continuous, heavy slewing, and measured again. Dropped a quarter of a volt.
So, what do ya'll think? How long do you think (on an average night of use) it'll last? The only thing it's powering is the mount.