300 lumens,
my guess,... MR11 bulbs, ~20 lumen per watt, reflector, and size does not make it very efficient, it would seam litle less bright than , LED , due 3000K , but that yellow light, would give you better depth perception,... of course 300 lumen is not enough.
I'am digging out my old mr16 halogen,... 20W over volted 27W, newer bulb,
will give me butter smooth 1000+ lumen, add an LED to make it whiter, voila,
usable, on expense of battery runtime. since I'am developing batteries, I do have mega, monster batteries, so I could still get 3.5hrs+ , it's a classic.
my monster halogen, is a 35W turbo boosted to 52W, pushing 1800 lumen+, + an LED,
but that be for shorter rides, 2hrs- ~1.5hrs. at least there is an option, without paying an arm an leg for LED light, thought, the batteries aren't cheap, and it's for the all-mountain / downhill guys, where an extra kg is not that important.
my buddy, replaced the 10W with an 20W on his niterider,... so far he has not melted the light, and kept it for long time, replaced his battery once, still rides HID on handlebar and dual on helmet, with the big heavy nimh bottle in his camelbak,....