2 low-voltage outdoor spotlight fixtures w/ 20W halogen bulbs: $24 (Home Depot)
12-volt 6-amp motorcycle battery $35 (auto supply store)
in-line 12V fuse holder and box of assorted fuses $3 (auto supply)
1 55 W outdoor halogen spot bulb to substitute for one of the 20 watt bulbs
dual dc switch and miniature case $5 (Radio Shack)
spare 2-wire extension cord $free (garage)
misc zip ties and bungee cording $free (garage)
$70 total

Strap the battery to the back rack. Strap the lights to the handle bar. Run wiring from lights to switch box and then to battery. I run with 20W most of the time. When all 75W are running, it lights up the street like an airport runway. You can see signs five blocks away. Plus