For about $30 you could strap one of the Cree emitter flashlights to your bike. I have the 5W Dinotte light but have found that one of the flashlight to have a better flood/throw pattern (I can see better at night) than the Dinotte. It's not an elegant solution and I have not tested the runtime of the flashlight yet (though it's not like the Dinotte runs all that long either) but for $30.00 it's a pretty good deal for a backup light. The big catch is that the light I have uses CR123A batteries instead of AA's.