BLF GT w/ SFT40 !!

Nice, I figured it wouldnt take long for someone to do this :smiley:
Would have saved time had this LED been around when the GT was made

i don't have the original xhp35 HI version, but I have to imagine this is similar but throws further.. I think? It lights things up in the foreground too. It's amazing lol, I'll how it in beamshots, been raining for 2 nights here now of course.

I thought I was the only one to put DC Fix on a thrower. :smiley:

5 meters, indoors, using a Extech LT45. This is how I've been doing all my throw measurements, least I'm consistent with my self

The original BLF GT that I measured at 5m did 857 kcd, but I have a note that the best # I measured at 5 m was 957 kcd.

I measure throw from 7 meters normally, but have the option for 12.5 meters. My original GT did not measure more than a few percent different for those two distances (can’t remember the exact numbers). So I expect that 5 meter will get close enough numbers too.

I used the driver from the BLF GT90 conversion kit and the biggest 5050 MCPCB I could find:

Took the original XHP35-HI centering piece and opened up the hole:

Tested amps using the long leads I did for reducing voltage/amps:

Pushing the limits:

Thanks for adding that Tom!

Okay… I was thrown off here by the format Artie used. 1803kcd or 1.8Mcd back calculated from 5m. The way I read it I thought there was a units typo and it was 1803lux @ x meters, which obviously would have to be ten for 2686m of throw. Sorry gents, carry on.

yeah that was my bad I noticed after you commented. I wrote it weirdly, should have put 1.8mcd

This is a great project that I would be excited to see, if the pictures were visible! I can't see any of the photos today.

That's not a terrible thing, most of them are pretty lame. What is the beam shots are posted it will be more interesting

edit, Tom's pictures are nice because they show the inside of the light, My pictures mostly show the inside of my house. Lol

  1. I think I have the same reamer but in blue
  2. Why haven’t the SBT90.2 conversions I’ve seen used the reaming technique for a centering ring?

Dunno - maybe because it's a lot of material to ream to convert it. Actually all the stock black centering pieces had holes too big. The one I reamed for the SFT-40 was the best fit one by far. The good thing about the stock piece is it seems to center nicely aligned to the screws. The screws actually down hold anything down. I probably should have put a little dab of silicon glue on the threads to hold them in place.

Just there to prevent rotation?

Yea, stop rotation and center alignment.

Third day of rain today. The universe is making me wait to do these beam shots. I almost did it last night but the mist was too much.

I’m wondering if Tom would put one of these LEDs in an older Supbeam K40 or a TN31

Actually I got both - A K40, resistor tweaked w/dedomed XM-L2 and a TN31, think resistor tweaked, with a stock domed XM-L2. I think the TN31 is under-performing even for a dome XM-L2, but the K40 does ok but never does as well as a TN31. The thing is I'm thinking I'm not going to be able to get more amps out of those lights, and not sure what amps they put out right now. I'd have to carefully test the amps before even attempting an SFT-40, since they are sensitive, as I'm finding out. Burnt 2 of them out yesterday in a modded 3X221A.

All depends on the amps. If I can get only 6 to 7 amps, then results would be so-so. If those lights can do 8-9 amps, now we are talk'n, but 10+ amps -- watch out! I'm hoping the way the modded driver works, the amps will be the same disregarding the LED Vf, but maybe that's not true - maybe I'll get more amps with a SFT-40 running at a lower Vf. Not sure how it works.

All depends if the amps are the same, how a dedomed XM-L2 compares with a SFT-40.

The 2 I want Modded are stock — I have a K40 modded by Vinh with dedomed XM-L2 (Fiat Lux pdtn led —it was his version of a perfect neutral tint after dedoming) It’s actually my favorite thrower —perfect beam — If I remember correctly (I’m old ) I tested it at 412 k throw — the thing about these two lights they’re fully regulated and heat is no issue

Let me know if you figure something out with the K40 — I’d be interest in a Tom E version — what tint is the SFT 40

Just tested my K40 at 341 kcd, on low qual batteries, modded in 2013. I'm thinking the resistor mod is light. The SFT-40's are only 6500K for now.

You are right about the regulation - low amps back in the day, but love the mag ring to set the output level on these lights!

Again, same K40 on 30Q BT's: 349 kcd, little better, didn't expect much because of the driver's regulation.