These are the things you will need:
A for the light:
1. a supermarket light with quickrelease handlebar-mount which will cost you almost nothing because everyone has tried
one yes ? Remark : it has to be big enough to fit the choosen lightbulb !
2. a Dremel work and do-all tool set
3. a halogen lightbulb, preferably with a glass protection.
choose one that throws out the heat in front .
12V 20 W
4. a bulb ceramic fitting
5. a piece of aluminium plate
6. screws that will fix the fitting on the aluminium plate
B. for the battery:
1. a battery with enough breath
12V 3,4 AH
2. a fuse and fuse holder
3. some electric wires
4. And some connectors by choice to connect battery and lamp.
5. A cool bag to put the battery on you frame