# BLF GT (preliminary) modding thread

No! You are argueing against simple physics. Sorry, but I have to write that.
The luminance of the LED and the front surface area of the reflector/optic are the only thing that matters for actual throw/distance. They determine how bright the hotspot is in the center. The reflector basically just multiplies the luminance of the LED.

Maybe another example:
Lets say you have two identical lights, for example two Convoy C8 lights. Both do 50kcd. When you hold them next to each eather so that the beams are parallel and overlap in the distance, you will get 100kcd. It simply adds up. This is the same thing I described above.

You not being able to make some cheap Chinese light with unknown properties throw further compared to some other light doesn’t really prove anything. We would need all the numbers, all the little details.

You are arguing against simple optics…?

I’m not sure anymore.
One says this, the other says that, both make sense, but in reality my 168A sucks at throwing, but others seem to have had better results.

I think this may illustrate things better:

(from the reflector depth discussion in the GT thread)

Around 45° is ‘where it really counts’, and in this case the focal distance around that angle is 20% larger for the shorter reflector, which is around 20% shorter than the tall one.

Okay, i’ll just conclude that it doesn’t make a lot of difference then.
And that’s the end for me on this thread derailment.

Another example:
Take two LEDs and compare how much Candela they manage in the BLF GT.

1. A de-domed XP-E(1) @2A

2. A XP-L HI v3 @7A

The XP-L HI will throw further even though it’s 3.5 times as big (the die). Accordingly the spot will be 3.5 times as big when using the same reflector.
Why? Because it is so much more efficient that it manages a higher luminance at 7A.

Well, you forgot to mention the fact that this emitter will fade away in no time, speaking of personal experience ofc, especialy if that flashlight is moderately used

A dded XPL wont die that easy though

XPE2 at 2.5 amps will beat any XPL Hi /even dded XPL and will run and sing at 2.5 amps for a very long time

Kenjii, can you talk about the Osram Synios? Seems there are with different die sizes.

No, I don’t think so. The XP-L HI needs to be actually driven hard with a buck driver and multiple cells. Of course in single cell lights it’s not as good.

You are the only person I know of who reports problems with the reliability. There must be more…

Ever tested that m8? Cause i did, dozen times, and after a month the fella hunter is calling: the emitter has a black dot( usualy arround the wond wires)

Ofc at 4.5 it will live, yet it wont be that productive.

I use hard driven Hi emitter unless i dotn have other choice( for those “cool white” fellas)

Warm and nautral white HI emitters do have even more issues though

Yet now, after 8000k SST emerged i dont think i will be using a HI emitter any time soon

Whether it is worth it or not is up to the person buying the reflector.
Yes, most of the additional lumens collected by a deeper reflector go into the corona, this is correct, but there is still a bit more front area to the reflector due to the smaller center hole, which is what increases the lux a little.
A deeper reflector, assuming constant diameter, means it will have a smaller center hole, and more front area as a result.

So the increase in lumens is pretty large due to all the extra degrees collected, but the increase in lux is very little since the center hole size won’t decrease much.
It still does increase the lux, just very little.

As the BLF GT thread has so much clutter, I thought it was nice to copy Texas Ace’s findings to this thread:

Kick!!!

Any plans to mod the GT?

I was looking at the SST 90 led from luminus http://luminus.com/products/SST-90.html.
Double lumens and smaller die als with the XHP70.2 thus more throw.
Only problem would be to find a driver. The led4power drivers might work? (1s4p carrier setup of course)

Nope , l4p drivers can’t handle that much current .

You have to use a fet driver like fet+1 or TA triple channel .

T/A mentioned that he might make a parts list to make the GT driver compatible with 3volt LED’s.

I’m very keen to go that route, & have some of the ‘good’ XP-G2’s on their way as well, which should punch out some really good throw numbers.

For comparison, I’ve taken throw readings on the STOCK production GT. Using 8*30q’s fully charged, I calculated the following readings (to 0.25lux), using a CT-1330B light meter.

Taken @ 10 meters - 1760 meters throw.

Taken @ 15 meters - 1764 meters throw.

Taken @ 20 meters - 1743 meters throw.

Can those who are able, post their NON-MODDED ie STOCK production GT throw numbers, & what cells & meter used also.

EDIT - see post #68 - possible faulty meter.

Still waiting for a 70.2 mcpcb to fit the GT.

That and a driver that can handle 11A/12v or 22A/6v w/NarsilM would be great.

I received my GT a few weeks ago. I love the light, especially the 4000k tint. My LED was slightly off center due to some very minor slop in the centering apparatus. I wanted a way to get consistent centering of the LED. To address this, I spent some time filing down a centering ring to fill the void. It did not come out perfect, but I am satisfied with the result I got, especially considering that I only used hand tools.

The head was VERY tightly screwed on. Removing the head was the most challenging part of this project. I had to make a crude strap wrench and clamping fixture to loosen it. I have not removed the bezel yet and am not sure if I will attempt to.The reflector is a tad bit dusty, but it does not really concern me. I lubed the heck out of the head before putting it back on (visible in photos).

Here are some size reference photos next to my ‘other’ superthrower. The GT is absolutely massive. The lux meter goes back and forth between the 2, so I estimate they are about the same in terms of throw. The chrome light is a Fivemega Elephant original with 3 series 18650 carrier, DX 78mm aspheric, wavien collar, modified h22a heatsink, xp-g2 s4 2b (old style), driven by TaskLED h6cc at 5 amps. Plans are to install an Osram Synios fairly soon. The GT will most likely remain stock other than the centering ring enhancement.

That elefant deserves its own thread

I like both! :+1:

Did you mod the Elephant yourself?

Where did you get the wavien collar from?

I did build the Elephant in 2014, back when wavien collars were available for purchase. I’ll post a thread when I upgrade it. Thanks!

This evening, I swapped the stock 4000k XHP35 HI with a 5700k XHP35 HI D4 bin.

This is the same LED being offered by MTN for transplant, for people who don’t like the stock LED.

Using 8*30q’s fully charged, I calculated the following readings (to 0.25lux), using a CT-1330B light meter.

Taken @ 10 meters – 1833 meters throw.

Taken @ 15 meters – 1849 meters throw.

Taken @ 20 meters – 1841 meters throw.

Taken @ 10 meters – 1760 meters throw.

Taken @ 15 meters – 1764 meters throw.

Taken @ 20 meters – 1743 meters throw.

While the GT is a great thrower, & will wow most people, unfortunately it falls short of the “>1 Mcd (ANSI throw >2000 m)”, as promised in the original specs, which is a little disappointing.

Of course, I’m just using a cheap, un-calibrated meter, so there’s bound to be a little give or take in the numbers.

I’m looking forward to see what it can do with an XP-G2

EDIT – see post #68 – possible faulty meter.