I'm interested in making myself a 12V power supply. I need one because I often go out to places with little or no power and need some electricity to power my gear (which is basically a telescope, a camera and some accessories - all run on 12V).
I don't want it to be powered by mains and would instead use a 12V deep cycle battery. For regulation, I'm going to be using 7812. I need about 6 outputs, each capable of 4A. My question is this:
Is it better to regulate each output separately with a 7812 (with a power transistor for increased current capability) or use single 7812 with several power transistors, for a current rating of, say, 25A, and then split this into 6 outputs.
Secondly, since I'm using a 12V battery I understand that regulation is not going to be good as Vout is also 12V. Unfortunately, I can't get a new battery so I was thinking, perhaps, stepping the voltage with a DC-DC Converter to about 14V and then feeding this voltage into the regulator will help with regulation. Is this a good idea?
I require some decent regulation as my telescope is quite sensitive to the power's quality. I apologize if these are boneheaded questions, but searching the web did not return good results.