As Leon says the Gemini can operate between 12 and 18V and the power supply we use is regulated. I'll be up the observatory on Tuesday night and I'll have a look at the brand we use. I did have to perform a bit of surgery on it though as the unit didn't have two separate positive and negative terminals just a plug that would plug into a number of adapters for use with laptops. I do remember the specs were 12-18V, 5 Amp and up to 150W.
if that means anything to you.
