Originally Posted by Sloth
According to this:
http://nordicgroup.us/s78/#Watts%20Versus%20Lumens
A 10W MR16 is putting out 400 lumens, quite a bit more if you overvolt it a bit.
My HID would appear to be putting out about 600 Lumens, and that is about what I would consider minimally acceptable for fast night rides.
I'm not quite sure where he's getting 400 lumens, because most of the information I've been reading, and you can google it: "lumens per watt halogen calculation", gives about 20-lumens per halogen watt:
therefore, on the high end, i've seen 200 lumens for 10-watt halogens. and that is pure math. depending on which halogen you get, they have real-world wattage vs. the reading in a test-chamber, so it can range between 140-200 lumens..