View Single Post
Old 02-02-14, 07:34 AM
  #25  
zacster
Senior Member
 
Join Date: Jul 2004
Location: Brooklyn NY
Posts: 7,728

Bikes: Kuota Kredo/Chorus, Trek 7000 commuter, Trek 8000 MTB and a few others

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 22 Post(s)
Liked 464 Times in 365 Posts
Yes, a Cree XML-U2 will put out up to 1040 lm, at about 100 lm / W. A single 18650 battery will put out 3.7v and 2.4 amps in an hour, which is about how long they last in most configurations. That's about 9w. So let's not be generous and say you get about 40% efficiency, that would be 360 lumens. At 50% you get 450. etc... If you are only getting 100 lumens from one of those, you are choking off the power to the lamp. Below is straight from the Cree website.

Maximum drive current (A) 3
Maximum power (W) 10
Light output Up to 1040 lm @ 10 W
zacster is offline