Originally Posted by
SylvainG
A CREE T6 will produce 800 lumens given enough power (at 3A and 3.35V, a T6 will do about 1,000 lumens but that's 10W of heat to dissipate!), which the Volt800 can do and like you said, because of how Lithium battery works, it can't give 2 straight hours at 800 lumens out of that battery. Voltage will drop as soon as the light draining power and at full brightness, that's a lot of power being drained from that single 3.6V battery Lithium battery. On the Chinese light I had, it had four 18650 battery (two in parallel/series combo). CREE LED nominal voltage is 3.2 volt so the battery pack has to regulate voltage from 7.2V to 3.2V. Dropping 4V and sinking 2A from that regulator (8W), would create lots of heat (more than the LED itself!), hence why I guess they can't produce the rated lumens, their circuitry can't handle it.
I still think you are underestimating the Chinese lights and their abilities. I've compared a light that is supposed to put out 800 to 850 lumens to the Chinese Crees that I have and the light output is similar. The known light is actually a bit dimmer. And, given the number of times that people have flamed me for having lights that "spray light into the trees" and "blind people because they burn out our retinas", I know these Chinese lights are putting out more than 200 lumens. A Petzl Tikka puts out 200 lumens and my lights are much brighter than that.
That said, there are many of the USB lights out there that are putting out 1100 lumens which, according to the We Test Lights website is a measured output. However, looking at the charts all of the USB lights seem to have the same problem which is just as dishonest as the claimed 1200 lumens output of the Chinese lights. It's not the "true" output since it is only a spike and then quickly it drops off.
Originally Posted by
SylvainG
Like I mention elsewhere, I hardly ride in full brightness, but it's there when I need it. I'm mostly in HyperConstant mode and will switch (by a quick double press of the button) to high mode when conditions requires it (like when a car coming toward me with his hi-beam or riding fast in a completely unlit path) so even after my 1 hour ride, light output is still strong and constant. If however this would become a issue, I could swap the battery with a fresh one. This, in my opinion, is more practical than carry 3 cheap Chinese lights on my (already crowded) handlebar with their corresponding battery pack hooked on my top tube, but that's just me, each his own.
I, on the other hand, always run at full brightness. I see little to no use for any other mode...especially flash mode. The only time I power down is for a very short section of bikepath that I have to ride to connect to another street. I refuse to ride bike paths at night...it's mostly illegal here anyway...because I don't want to blind pedestrians who are walking without lighting. That means that I have to compete with car lights so dimming lights isn't an option. As I've also said, the lights I have put out much more than 200 lumens on full power. Yes, they put out about 200 lumens at low power but they are a lot brighter than that at full power. I have 3 of them...two on bars and one on helmet...but they are throwing out a lot of light. In my experience their performance...not output but the consistent output to battery drain...is more like the
NiteRider Pro than like the charts given for the USB lights.