XM-L T6 drop in module options

When I Google Cree XM-L T6 drop in module, I get dozens of hits for the product from suppliers such as Amazon, DX, Fastech, etc. offering this product ranging from 450 lumens at 1500 ma up to 1000 lumens at 3000 mA. When I look at the Cree Data Sheet I see information indicating the design is 1000 lumens at 3000 mA. How can the Cree XM-L T6 drop in module be offered in so many different lumens and driving currents? I'm obviously ignorant about electronics so I would appreciate some assistance wading through this confusing maze of possibilities.
My goal is to use one 18650 Li-Ion battery to throw between 500-1000 lumens continuously for 2+ hours before changing out batteries. The challenge is to choose the correct Cree Cool White LED drop in module and the correct capacity 18650 Li-Ion battery (2900-3600mAh). Please help.
Signed
Overwhelmed

The reason you see such wide current ratings from sellers is most of them are making unrealistic claims. Most of the drivers used in the "assmbly line" P60 modules are the 1 amp versions. Which are pretty generic. And its rare to find one that is constant current. Meaning that at the lower end of its voltage range it will draw more current. Most are right around 1100mah to 1400 on a single 18650. Put in 2 primaries and it will drop down. You would be better off looking at one of Nailbenders P60's. He has a large selection to make your choice and his quality is excellent.


If you buy a $12 P60 that is basically what you will get. Small wires off the driver board, fujik bonded MCPCB and poor soldering. Get one from Customlites and it will be of the best quality possible and it will take anything you can throw at it. Look at the Panasonic NCR18650B for your light. 3400mah and if I were you get the protected version for safety reasons.

You may need to adjust your expectations down from 1000lm for 2h on a single battery to maybe a more realistic 1h, but yeah. Illuminationsupply.com has some nice-looking eagletac "Sportac" dropins, including an xm-l2 that should put out ~1000lm. Assuming 10W, you need 10Wh to power it. Assuming flat discharge curve at 3.7V, you would need a 2700mAh cell to power it for that long. Of course, batteries don't have a flat discharge, their voltage drops gradually over the discharge time, so your results will vary, but a quick back-of-the-napkin calculation does show that 1h is more likely doable than 2h.

Robert Hailes said:

When I Google Cree XM-L T6 drop in module, I get dozens of hits for the product from suppliers such as Amazon, DX, Fastech, etc. offering this product ranging from 450 lumens at 1500 ma up to 1000 lumens at 3000 mA. When I look at the Cree Data Sheet I see information indicating the design is 1000 lumens at 3000 mA.

Click to expand...

That first one actually sounds like it could be reasonably accurate figure; here's another quick'n'dirty run-down that might help:-
You've obviously found the Cree datasheet, which is an excellent start :thumbsup: Near the start you'll see "Flux Characteristics"; for the T6, you'll see it's rated as 280lm @ 700mA. Jump down to "Relative Flux vs Current"; you'll see a percentage vs current. Times this percentage by the rated 700mA figure you found above; this is how you can use the same graph for all of the differnt bins. So, @ 1500mA it's about say 195% = 1.95 x 280 =~ 550lm. The first drop-in you mentioned says 450lm @ 1.5A, rather than the theoretical rated 550lm, which means it sounds a bit more like a plausible "real world" rating.
If you look then at 3000mA it works out at about 325%, so a T6 should have a theoretical output of 910 lumens (280 x 3.25), not the 1000 listed for the 3A one.

Note then that this is all for a 25celcius reading; if you look at "Relative Flux vs Junction Temperature" you'll notice that for the more real-world junction temps of say 85celcius, the output drops below 90% of the figures mentioned above.

Then on top of all that, this is all just the output at the emitter, if the required current and voltage is available; actual out-the-front (OTF) lumens will be quite a bit less, let's say 3/4, due to reflector/lens/glass losses.


So in a nutshell, lots of manufacturers/sellers make statements based on theoretical maximums at ideal temperatures etc., but if you can get info on exactly how much current the driver can supply etc you can make semi-educated deductions as to what you should be seeing from it in reality.
Oh, also remember that 1000lm doesn't equate to twice the brightness of 500lm, so running the XM-L cooler for longer at 1.5Amps may prove better than running it hotter for half as long at 3Amps.