My canlight plus a minor mod

[lautmaschine]

I finally put together my 5xCree Mag lite, using 350xfire's screw top canister and boro lens.

Elsewhere on the forum I found a schematic for the 5xCree driver, and learned the forward current isn't much more than 700ma. There are two sense resistors soldered in parallel ('piggybacked' on top of either other). It seems that older versions of the board had a 4.7ohm resistor on top of a .82ohm. Newer versions have a 10ohm resistor on top, bringing the forward current down to about 650ma.

I removed the top sense resistor on my board and put a second .82 (1206) on the existing .82 bringing forward current to 1200ma. It was an easy mod that increases light output.

 

[350xfire]

Pictures please?
Thanks

 

[Klem]

Which one is the 'sense' resistor? A photo would help.

 

[lautmaschine]

No problem. The sense resistors are marked in the red circle, right next to the ground wire going to the LEDs. You shouldn't have to bend the inductor away (as in the photo) to access them. However, depending on which version of the board you have, there may be a large electro cap that you'll have to bend up for access.

As I mentioned before there are two sense resistors wired in parallel (mounted directly on top of each other). A 4.7ohm resistor will likely be marked 4R7, whereas my 10ohm resistor was marked 100. Underneath you'll likely find a .87 ohm resistor marked R82 (or maybe R820).

Thanks to 350xfire for the excellent parts. I still have a couple things to do, such as add a switch guard and strain relief.

 

[baywatch106]

nice, I have one of Hectors other can lights.

 

[350xfire]

That's cool thanks for the tip!

 

[lautmaschine]

Ref voltage is 0.5v, so if you're interested in experimenting with driving the LEDs, use 0.5/A=Rsense. In my example, 0.5v/1.2A=0.42ohm. If you're using two resistors in parallel, R2=(R1*Rsense)/(R1-Rsense), therefore 0.82=(0.82*0.41)/(0.82-0.41).
Check out this thread to see the driver schematic and other ideas on making the board operate more efficiently.

With good heatsinking, one might see 1500+ lumen from this design.

 

[jspeybro]

By default, that driver is a multimode driver. If you want a single mode, just move the ground wire of the LED (LED- connection) to the sense-resistor.
If you want to run it from a higher voltage, there's a cap that needs to be replaced. there's a whole thread about this driver somewhere on the forum.

 

[Klem]

By default, that driver is a multimode driver. If you want a single mode, just move the ground wire of the LED (LED- connection) to the sense-resistor.
If you want to run it from a higher voltage, there's a cap that needs to be replaced. there's a whole thread about this driver somewhere on the forum.

I use the single-mode version, which is also for sale on DX.