Originally Posted by
jsdavis
I just put a 500 lumen LED flashlight on the front of my commuter and it seems automobiles behave a bit different at night compared to when I only had my Planet Bike Blaze which I actually found pretty useless for illuminating the road.
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With a 18650 battery, it'll only go about 2 hours, but that's enough for 3-5 days of commuting and errands.
The "rated 900 actual about 400 lumen" P7 lights will last about an hour on a single 18650 battery on high, so if yours lasts two hours the odds are good that it's really about 200 lumens.
Either way though ... having a good light makes a large amount of difference. Not only can you actually see things in the road, but cars rarely miss you. (And occasionally other cyclists think you're a car coming up behind them, which is always fun.)
As for the beam pattern, I've got a few various lights, and have one that allows me to adjust the beam pattern and has a lens over the lens in addition to the reflector. I like to have it aim far down the road, and then use another light that has no lens (just a reflector) that has a rather ugly beam pattern to illuminate the road closer to my bike. And then I keep both on medium so they'll last four fours or so.
And wide beam patterns aren't always a bad thing -- they may not illuminate exactly where you want to see, but they do help others see you. As already mentioned, a light with a tight beam pattern is hard to see if you're not in the beam.