Custom P60

[llmercll]

Hello!

I was looking for a low voltage XM-L drop in but couldn't find any, so was going to build my own. I'm thinking of using these parts

DX SKU 25505

DX SKU 51989

I'm a bit confused on whether or not the LED works with voltages lower than 3, though. Does "Working voltage: 3.0~3.5V" mean that a single AA won't work, even though the circuit board is compatible?

thanks!


Please Do Not link directly to sales sites - Norm

 

[RedForest UK]

The point of the driver if it's a low voltage one (boost circuit) is to boost the voltage of the input to match the forward voltage of the LED. If the driver works at low voltage it will make the output voltage to the LED what it needs, but the LED will get proportionally less current output to it than is drawn from the cells.

If you used those it would work at anything over the driver's minimum input voltage. However current would be very low and there would really be no benefit to using XM-L over XP-G etc at those currents output wise. It's probably also worth considering that the 20mm star which that XM-L is on would not fit in a standard P60 pill.

 

[llmercll]

Thank you very much for pointing that out for me, and for the informative reply =)

I currently have a low voltage XPG R5 drop-in being used with my Solarforce L2r. You really think there would be no benefit to the XM-L? Perhaps that's why there are none on the market =p

 

[RedForest UK]

The XM-L is only really around 10-15% more efficient/brighter at the same current than an XP-G, but with a wider emission angle, so lower surface brightness at the same currents, so it is much more floody with little brightness increase. The main benefit of an XM-L is that it can be driven way over the 1.5A max of an XP-G for much more total output in high current lights.

Unfortunately AA cells and boost drivers are not really capable of providing enough power to the LED to take advantage of this. So, at the drive currents which 2xAA and a boost circuit can provide you won't see much, if any, noticable benefit from using an XM-L.


If you want a 2xAA light that is brighter then check out the Jetbeam BA20 from shiningbeam or somewhere. It uses a copper star for the LED, has very efficient circuitry and coated lense etc and so manages to maximise the output from 2xAA through a high binned XP-G R5. These small incremental efficiency gains mean that it outputs much more light than would otherwise be expected, and more so than an XM-L based version would without them.

 

[llmercll]

Thanks for this information, It's been very helpful!

I think I may pick up a few "stars" of different LED's and experiment a bit =)

 

[llmercll]

I ordered a few stars, driver, and a pill. I'm wondering how I can easily test different LED + driver combos without having solder and glue (which I will do as a final step of course). I'm also curious as to which wire I should use to connect the driver to led module, 20AWG?

thanks!

 

[llmercll]

Anyone?

thanks!