Vincent,

This is a great idea. I have a halogen set for my bicycle but as you say, the batteries don't last long. My sealed lead-acid that came with the lights died quickly so I replaced it with Ni-Mh AA batteries. I've been thinking of switching to LED headlights.

I'm currently designing a pair of ring lights for my motorbike side lights and have found super bright LEDs on ebay which claim to have up to 10% of the light output of a 100W incandescent light bulb. I'm planning to use 28 of them - equivalent to 280 Watts of incandescent light. I'll let you know how I get on. The LEDs have a 3.15 Volt forward voltage and 100mA current, so 4 in series can run off 12 Volts - or 2 in series can run off 6 volts (the forward voltage drops below 3 volts for lower currents but the light output is still high enough).

The secret with LEDs is to get ones with a wide enough viewing angle and high enough millicandela output to throw enough light on the road.

Regards,
Paddy O'Reilly