U2 brighter on rechargeable or ?

Since the U2 is regulated, is it brighter on rechargeables or 123's? Is there any difference?

Bill

Depending on the Vin of the LED in your light it might be a tad bit dimmer on the high level when used with a Li-Ion.
bernie

Has anyone yet tried running it on R123's? like on 8 volts? How zat work?

have not tried 2x R123 with no plans to.

My low serial # intial release U2 is not getting anywhere near Surefire customer service

no way I'm risking hurting my U2.

U2 and 18650 were made for each other. I'm doing several hour long runs on my bike. carry two spare 18650 in my pack.

brightness w/18650 is slightly less than with 2x CR123. but who cares. been ripping thru cell lately doing lots of night riding on my new Lightning P-38 recumbent.

Just about as soon as the battery voltage exceeds the Vf of the LuxV (usually a bit above 7 volts), the U2 is no longer regulating. You can't even dial down the brightness. Which means that two R123 cells in a U2 will seriously overdrive the LED.

The U2 is generally brighter on two CR123 cells on level 6 than it is on a single Li-Ion like an 18650, but not by much. In the three U2s I have tested, the 18650 gave about 10% less lux than two CR123 cells. Over the next 90 minutes, the output on the 18650 dropped another 10% or so until falling rapidly to moon mode.

You lose a little bit of brightness on a single 18650 at level 6 but all other levels perform as expected. We had a luxmeter at one of our local gatherings, 385 lux - surprising considering all the L5s at the table were 500+ lux. Someone offered to lend me two CR123s to put in the U2 and straight away it shot right back up to 550 lux. I later found out the 18650 was heavily depleted.. busy week at work.

Cy,

That's quite the combo of annodization on the U2!!

Mine is perfectly even black, is mine weird or yours?

Bill

Cameras tend to show it up. It's not so visible in normal light.

That having been said, the A2 Black limited edition lights ARE perfect, whether in front of the camera or in person. Oh well, guess they could control the anodizing better on a LE light.

cy: That is a nice mount you have for your U2...may I ask where you purchased it? Is it just velcro strappng?
Thanks! Dave

pictured is a twofish block

IMHO it's the best bike mount available without getting into a custom, like what Niterider or other mfg uses.

there a thread going with details on how to buy

http://tinyurl.com/d6hnj

Cy: thank you for the link !

wasBlinded said:

Just about as soon as the battery voltage exceeds the Vf of the LuxV (usually a bit above 7 volts), the U2 is no longer regulating. You can't even dial down the brightness. Which means that two R123 cells in a U2 will seriously overdrive the LED.

Click to expand...

I have put two RCR123 batteries on my U2.

The regulator at level 6 (maximun), 5 and 4 doesn't work, (the light is still at max power), but the levels 3, 2 and 1 (minimun) works well...

Do you think that I'm putting on risk my U2 ?

Thanks.

Edit: Lighthound says that this combination is Not Recommended . . .

bwaites said:

Cy,

That's quite the combo of annodization on the U2!!

Mine is perfectly even black, is mine weird or yours?

Bill

Click to expand...

If your U2 is perfectly matched black, then it's the weird one.

The U2 and 18650 are, as cy said, made for each other.

I thought my U2 was perfectly matched under the combination fluorescent/daylight in my office.

Close inspection, however, reveals that it has the same color schemata as the one above, though with significantly less contrast than that light.

Having taken a few pictures with flash of the U2, the differences are more apparent.

At this point, I think the angle and type of lighting make a significant difference in the apparent coloration of the light.

That said, the A2 appears to be PERFECTLY matched.

Evidently, production run lights are not batch matched when annodized, but the Special Edition or special run lights are.

Bill

BTW - Using an LG 18650 2400mAh, I lost about 8% on level 6, but only on level 6, while runtime ran just over 90 minutes before level 6 dropped out. Levels 5-2 drop out a few minutes later, but level 1 ran for a while longer. I posted all this months ago, but I haven't clue where the thread is.

RayBob's Cow Tippin' Flashlite Comparison does have a chart showing my U2's output for SR123's and a Pila 168A. I prefer the 18650 though, as it runs a bit longer.

I wonder if cy did some processing on that pic to make the differences more noticeable. Mine aren't that obvious. I do remember my DX-50 flash making the differences jump out, though. I bet it is due to different reflective properties of the different components, in combination with a flash.

Ray,

I hadn't read that in a while, glad you found it, I laughed almost as hard this time as last!!

Guess I need to get some 18650's, anyone have a good source? Does 4sevens still sell them?

Bill

U2 photo is untouched, for some reason that shot magnifies HA color diferences.

in real life HA match looks pretty good. more like this photo of same U2

Cy,


That's what mine looks like! Obviously, the anno reflects or absorbs some different spectra, making that big difference in some photos.

Bill