I upgraded TK75 xml u2 to xml2 u2, but the result is no difference on the ligjt meter.
I dont know why? Anyone can give me answer?
I upgraded TK75 xml u2 to xml2 u2, but the result is no difference on the ligjt meter.
I dont know why? Anyone can give me answer?
Hi. Welcome to BLF.
Did you buy a new light or just replace the emitters? Because if you just replaced the emitters and the drive current is the same, you’d get next to no results. That is because in order for the second generation LEDs to perform better, you need a better thermal path and higher voltage. That forward voltage issue has been a thing members have discussed. Seems you have to drive an XM-L2 fairly hard to see any improvement over XM-L. Crank the drive up to 3.0+ and you’d be seeing a good improvement.
Just replaced the emitters, I dont know how to crank the drive up 3.0….
and my all single emitter light were upgraded to xml2 u2 ,
I can see that the result is raise ……i mean lumen and lux,
Dont need to do the diver up……why?
Just 3 emitter light TK75 no different……
Sorry my english is not good.
It seems strange that you aren’t seeing any increase in output at all.
Like for like output bins and same driver/drive current XML to XML2 emitters you should potentially see a boost in lumens of up to 20%.
It won’t be a massive increase in output but I’m sure it would be measurable, no change at all is a bit surprising.
You sure you tested with exactly the same charge level on the batteries?
The higher voltage requirements for XM-L2 only really affects linear or direct drive situations running from a single battery.
I don’t now what type of driver is used in the TK75 but the V/f differences between an XML and XML2 shouldn’t affect the drive current of a buck or boost driver.
Where did you get the XML2 emitters, maybe they aren’t genuine U2s. XM-L U2 and XM-L2 T6 (lowest available CW L2s) would give you about an equivalent output.
Does the output drop or sag after the light is on for a while, like after 30s. That may indicate bad thermal contact for the new leds and this will reduce their output dramatically.
Good point, I would start questioning the emitter bins as well.
All the batterys are 4.2V .
I sure the xml2 is true, not genuine.
Becasue i used its for single emitter light before, and they have increased lumen and lux
I dont know what happen to TK75…and the same problem also occur of jetbeam RRT3 XML to XML2 U2…
No different only occur of 3 emitters light?
The output drop is not for a while after on the light. Is starting on the light,
In the measurement of the light meter, The data is almost same between the both of light(TK75 XML U2 and TK75 XML2 U2)