Hello, I am a retired Electronics Technician after 28yrs 3mo in the Navy. I am currently a DOD contractor working on medium satellite earth terminals in Afghanistan. I have homebrewing experience as an EXTRA class HAM for many years.

OK, now for the batteries I just purchased. I have 4ea ultracaps that are each 3,000MF at 2.7V. Dimensions are 61mm diameter X 138mm length each. Each unit is rated at 3.04Wh available energy or a total of over 12Wh energy. I am trying to either make 2 lights with 2ea or 1 light with 4ea of these ultracaps. One other requirement is to have a removable red lens on it.

Not sure if I should use HID or several LED's. My plan is to get an aluminum tube to house the ultracaps. I would be just fine with borrowing the head from an existing flashlight if it is possible to do so. These caps are larger in diameter than a D cell (34.2mm X 61.5mm). I would like to get a good regulator circuit to maximize the potential energy. I read in a white paper that if I run the ultracaps down to 1/2 voltage I will use up 75% of the available energy if this helps understand my working range for the input on the regulator. This project is in it's infancy so any help suggestions would be much appreciated. I don't necessarily have a dollar cap on the project but would like to keep it in the hundreds of dollars range (not including the already purchased ultracaps).

Best regards,