I have the Princeton Tec EOS helmet light. Stays there year round. Always available. It runs for several hours on low. Low is enough to ride by. Not fast or great. But its enough. And I use three rear blinky lights with 2 AA or AAA lights. Usually only use two of them. Why the great interest in front lights on a touring bike? I would think you would plan to ride during the daylight. For rain and early starts, the EOS is enough to be seen. Why the desire for 3 or 4 different front lights? Once you have enough front light to see and be seen, more does you no good. Are you planning on touring through the night? Bit hard to see much that way.
My usual lights use AA or AAA batteries. They seem to last long enough. And batteries are easy to get.
you:Why the desire for 3 or 4 different front lights? I like to be seen in San Diego County and Southern California doing Stealth Bike Camping and I am Homeless by Choice since 11-2008 on Homeless Survival on SSI and SSDI and I go to Free Meal
Centers in San Diego County that start at 5:30pm done at 6:15pm and I start riding to my Stealth Bike Camping spot at 6:30pm and I get to my Stealth Camping Spot at 7:30pm it is dark out and I like to see the road and to be Seen by Cars, Vans, Trucks
#1 3 AAA Princeton Tac Push Bike Light 100Lumen for Bike Touring back up light!
#2 USB Cygolite Expilion USB 720Lumen and Spare Battery for
Cygolite Expilion my main bike light for Stealth Bike Camping and Bike Touring trips
#3 3 AAA Princeton Tac EOS Bike Light 105Lumen on Helmet back up going to
Cygolite Metro 550 USB bike light for Helmet use
#4 3 AAA Niterider Taillight 10lumen for back up for bike touring going to
Niterider Solas 150 lumen USB