In this case you are okay to find something like a Bell 3 LED set that runs on 3 AAA's (but the batteries are getting more expensive, Sunbeam super heavy duty cells at the dollar store have about 33% less batteries per pack than before...6 vs. 8-10 AA/AAA, 2 vs. 3 C/D...it's getting spendy to power all those old horns and Delta lights.

You want alkalines in those kind of lights anyway. And NiCads turn to mush in the cold, don't do that. In fact, stay away from rechargeable lights as much as possible on a bike.

I had the blinky taillight from a Bell set still running with a daily check for six months, even during the Snowmageddon that made it impossible for me to ride that bike. I have a nine LED flash/bike light that was given to me, maybe came from a Walmart and that thing will split the darkness in two.