First successful mod: XC-997 emitter replaced

Hi everyone,

I'm new here. I've been reading the forums, learning from all the knowledge here.

I had this light that came on one bike I flipped, very similar to XC-997 light available from DX (http://dx.com/s/xc+997) and decided to replace the emitter with something stronger. I had a bare neutral XML T6 from fasttech at hand, so decided to try that.

I heated up the aluminum board with a cigarette lighter and simply lifted the original LED from the board.

The original LED is 3.5 x 3.5mm (looks like XP-C, same size like an XP-G), but the XML is 5 x 5 mm. I scraped some of the paint to uncover the copper under it, shortened the conductive paths to the emitter bottom electrodes slightly (they are farhter apart on the XML which is 5 x 5mm). Then I covered the bare copper with solder, placed the XML emitter on the board and again gently heated the entire board with lighter until the solder melted and the new LED was fixed to the board. Then cooled it again as soon as possible with a little water on the alu board.



Then soldered back the red and blue wires from the circuitry, and slightly filed the hole in the reflector (from circular to square), but that's all.





All I can say is that the light with the new LED is crazy bright. Unfortunately I can't really compare the before and after output by measurements or by beamshots, but it feels like the amount of light has doubled.

The shape of the beam projected on wall looks very similar to the original XC-997 (http://club.dx.com/reviews/photos/82138/145961) but the bottom part is significantly wider and there seems to be more spill. I will try to get some beamshots if I can.

Nightshots please!

I'll try to get some shots.

I'm alredy thinking about swapping the XR-E in Cyo for an XM-L U2... just need to make an identical board because XR-E to XM-L swap would be difficult due to different size.

If you mod that one too, could you please make a photo comparation between them?

I took a 4AA battery holder, hooked it to the light and took some beamshots:


ISO250 f2.8 1/13s, daylight WB, from about 1m on white ceiling


ISO400 f2 1s, daylight WB, light about 40cm above ground and aimed a lot below horizon.

BTW: this is probably not the best way to take beamshots - are there any guidelines how to do it properly ? What power source to use and how to ensure repeatability ? For example the Cyo can't be power from DC - how can I take repeatable and comparable beamshots of it ?

OndrejP_SK said:

For example the Cyo can't be power from DC - how can I take repeatable and comparable beamshots of it ?

Click to expand...

Cyo will run off DC:
Connection to rechargeable battery
If you connect the headlamp to a rechargeable battery (entirely at your own risk)make sure to observe correct polarity, i.e. "plus" to the earth inlet and "minus" to
the current inlet. Maximum brightness is obtained at a voltage range between 7.2 and7.5 V (7.5 V must not be exceeded).

http://www.starbike.com/images/BUMM/PDF/175q.pdf

Thanks. I tried it but it wouldn't work - I'll try as you say.

Anything new?

Very interesting modification, I will probably try to do it myself. Atleast if I can find XM-L2 in 4000-5000K cheaply.

You mean something like this ? http://www.fasttech.com/products/0/10003889/1425000-cree-xm-l2-t6-4c-10w-1100lm-4200-4500k-neutral

I am lazy, so I am waiting for bare neutral XM-L2. Something warmer then this this http://www.fasttech.com/products/0/10003889/1277800-cree-xm-l2-t6-1c-10w-6500k-1052lm-led-emitter

Hi guys, after I'd done this mod, I actually ordered some XC-997 from DX because I think for the price it's a great base for modding. On one I immediately replaced the LED with an XM-L U2 2C, and one I kept with the original LED, so that I could do some comparisson beamshots.

One above another on my living room ceiling. The top is XM-L emitter, the bottom is the original LED. The original seems to have a very sharp cutoff - it would probably pass the German StVZO testing. The modded light has the brightest part far below the top edge, which is not good to light up the road in the distance unless you want to blind oncoming vehicles. See real-life beamshots what this hotspot in the middle of the beam means...



Here are 2 more shots from outside.
First the original emitter: it's not completely bad if you are riding fast on a straight road.



This is with XM-L - the beam is much much wider (IMHO much much better), but the cutoff is not as sharp. In this setting I could see some light reflecting on the wall of the appartment block in the distance, so pointing it even higher wouldn't be the best idea.

Wow... very nice.

I must say that the light output of the original emmiter is incredible, but can not be compared with the XM-L.

I've got some news for you. I tried what it would do to move the LED a little bit forward or backward to improve the beam shape (move the hotspot farther / up when projected on wall) and I found that moving the XML LED about 1mm to the back of the reflector moved the hotspot closer to the top edge of the beam pattern.

From this image it might not be so obvious, but when I see the pattern on the wall, it's clearly much better.

And this is what the PCB looks like before I attach the larger XM-L emitter - the pads from plus and minus need to be scratched through the paint and cut farther from the central I. I use dremel and a dentist drill bit.

Notice how I removed some of the conductive material from the emitter at the corners, so that I'd be able to move the LED 1mm backwards.

here is the beam shape of the latest version with the emitter positioned slightly backwards from the original position:
Note how the hotspot touched the top edge of the rhomboid. Compared to the picture in post #12 this one should give more light on the road farther and not blind the rider by too much light too close to the bicycle.

Very nice!

My dynamo halogen light just broke into pieces (literally), and I'm looking forward to buy this light, and run it off a dynamo.

Btw, what's the real output of this light (stock), and the real output of the one with XM-L.

khrystyan27: this light can't be used directly with a dynamo. There is no rectifier and no smoothing capacitor. You would need to make your own circiuit board to replace the original.

khrystyan27 said:

Btw, what's the real output of this light (stock), and the real output of the one with XM-L.

Click to expand...

I don't have light measurements, but I did measure the input voltage and current. It is current limited to 0.33A, and the limit is reached with an input voltage of 3.5v, IIRC. As such, it's only operating with 1 watt of power. This helps explain why there is no heatsink to the air outside of the light.