Need an inexpensive light??
 

Just rec'd my flashlight from DealExtreme. I had been visiting the electronics section of the site, trying to figure what type of light to buy. Lots of good info on building lights, but just wanted something I could ride around the neighborhood with, and not spend lots of money. Ordered a Smartfire V-68C flashight, a protected(against overchg) rechargeable battery, charger, and universal bike mount-total $43 delivered. That little flashlight will light up my neighbors barn well, and it is at least 100 yards away. Fairly focused beam, but not too bad a spill pattern, Amazing what the Cree Q5 LED emitter can do. For anyone looking for a light without spending lots-I can say this should foot the bill. Oh, and for the 50+ part--even my eyes, which require tri-focals, can see well at night now!

But is it lite?

Very nice. I'm looking to buy a couple of 2xAA battery flashlights, one to mount on the helmet.
I wonder how this compares to Fenix flashlights that many commuters seem to favor?

Being as they both use Q5 emitters, I think basically would be about the same. Here is a link to a shots of the actual flashlights for comparison which I found when considering which light to go with: http://ledmania.ceskyblog.cz/souhrn-...i/fotky-venku/
The Smartfire I bought uses 1x18650 battery, but they aren't that expensive, and after reading a bit, the 1x18650 seemed to be the way to go. Very happy with the Smartfire, can't imagine needing more light that it puts out (and my neighbor, from whose driveway we lit up the neighbors barn, said that barn is more like 150 yards, not my orig 100 yd estimate).

With a 150 yard range you sure won't be overdriving your headlight. Provided, of course, that you aren't traveling much more than ~80MPH.

50-100 feet should be more than adequate for the vast majority of speedy bikes. Remember others can see your light much farther away than you can see with it. Wide dispersion would seem to be important in order to make yourself visible to others and to see objects entering your path from the side.

Bike stopping distance calculator, unfortunately it does not say whether reaction time and brake type is considered:
http://www.exploratorium.edu/cycling/brakes2.html
Calculator requires a JavaScript-capable browser.

For reaction times and distances at various speeds:
http://www.jmu.edu/safetyplan/vehicl...distance.shtml

The 2xAA lights seem to have adequate power/life and the batteries are available anywhere.