Hello /diy/, I would like to build a very bright flashlight, but I got stuck deciding what the best way to go is. Basically I'm conflicted between HID and LED.

I'd rather go with HID since that produces more light, however I would need to build or modify a ballast to actually make it work. With LED it would be fairly simple electronically, but I will have to make sure the LED module doesn't overheat.

So would it be possible to build a ballast? They deliver a voltage spike to get a spark going, or did I get that completely wrong?

Would it else be possible to modify a ballast for car HID's to fit into a flashlight case?

With LED's is it really necessary to have such a big heat sink as in this video:
https://www.youtube.com/watch?v=c--5c3Egv4E
I was thinking about making my own metal case and then implementing fins into it to transfer the heat that way.

I imagined the rough dimensions would be 15-20 cm long and a diameter of 4 cm.

Would this be possible or did I get to ambitious?