BLF GT official support thread [FAQ updated 11 Jan 2018]

Got my GT this morning. Thanks Guys.

My tracking number has cleared Canadian customs and has now updated Expected delivery to 2018/03/29! Yay!

I used the contact form (via the site of M4D M4X) but did not receive a reply yet from Neal. I will try to contact Lumintop directly…

Does anyone know what the internal resistance of the included cells should be? Currently charging the first two in my C2-6000 and it’s showing me 78 / 82 milliohms. To me, that seems quite a lot for high drain cells.

Any thoughts?

The include cells(samsung 35E) is not high drain

I see - that explains it, thanks. Not familiar with the 35E cells, and thought they were similar to 30Q’s - should have checked HKJ’s site for Infos! Now I can relax, knowing that I haven’t been sold duds! :slight_smile:

The GT isn’t a high drain light. With 4 cells in it, at most each cell pulls 3 amps. With 8 cells each one only pulls 1.5 amps at most.

So it was decided that a higher capacity cell (3500mah) would be a better match for this light compared to a high drain cell like the 30Q (3000mah). You get more run time in total.

I do get that the light isn’t going to draw a lot of current, with only a single XHP35. But in a previous thread (about the Emisar D1?) it was mentioned that although high drain cells weren’t required, they were nevertheless recommended, due to the lower voltage sag. But with only 1.5A drawn from each cell, I guess we’ve probably entered the area where even voltage sag becomes negligible, if I understand correctly?

The GT was tested with 30Q and Panasonic 3500mah cells (2A at the emitter). Which should be pretty close to the 35E cells.

You’ll note that with the 30Q it stays in regulation a bit longer due to less voltage sag, but the 3500 cell has longer run time. So it’s a bit of a tradeoff.

Anyone else found the 30Q batteries to be a bit too loose in the carriers?

I assume you mean the springs are not compressed enough to keep the battery from wiggling side to side?

This is normal. The carriers are designed for both short and long “protected” cells. So that is about 65mm to 71mm. With a short cell the spring is only partially compressed.

What about the swap of the original led to the CFT-90 one?
I wait until some other guy tries this,so as to see if it is sensible to raise the high cost of the procession.

Vinh over at Skylumen is doing this swap. It has nothing to do with Lumintop or BLF.

Indeed it is a nice mod but not practical for production. So it will be left to modders to do it.

Besides there needs to be SOMETHING to mod or it would not be a BLF light lol.

If you can check my understanding, I would really appreciate it. I do not understand this stuff too well. Looking at this chart, I get the impression the BLFGT does not have to step down to avoid overheating. It looks like it can run at max output as long as the batteries can run. Is this partly correct?

It does not overheat. It will step down if you add heat to it like with a blow torch, but with just the emitter, it should not get hot enough to step down.

At 2.5A, the xhp35 only puts out about 36 watts and the flashlight body is massive with lots of surface area.

The general rule of thumb with really big lights like this is that they can usually sustain about 4k to 5k lumen continously. Some can do 6k and I think the best is the Imalent DX80 at about 7k lumen continously. Any higher than that you’ll need to either step down the power or add active cooling.

Correct, even under extended loads it only gets up to around ~55-60c IIRC, which is still considered “safe”.

The thermal protection is set from the factory at around 65-70c I think.

Now an XHP70.2 is another story, that will need a thermal stepdown but it still lasts a long time before overheating.

Thank you for the information, much appreciated.

I am sorry if I should have seen this elsewhere, but has an an XHP70.2 been run in a GT host yet? I am curious about the candella/throw figures.

Also, am I correct in understand the gt with the XHP35 is the strongest thrower in a hand-held light? Hummm, I guess Vinh can put a new type of LED in that has a smaller diameter making the whole throw process more efficient.

I am picturing Earth with 850 BLF GTs, imagining that apart from maybe a few dozen custom built exceptions, those 850, soon to be 1500, BLFGT lights are the most powerful hand-held throwers ever built. To me, that is so awesome, with a small caveat. The caveat is: it is awesome if true!

Is it true?

Yes, I have 2 xhp70.2 GT’s now. The first one I built with a modded stock driver a few months ago. I tested it at over 1300m of throw with the dome on and ~1600m of throw with the dome sliced off.

Lumens were around ~7000-7500.

The GT is the furthest throwing production LED reflector light in the world right now. With another LED it can throw further but at the cost of something else, either lumens and spot size or cash.

I just got my BLF GT in today and it’s now dark.

I just realized that the battery carriers are protected against flat top cells, and even my solder-blob-top cells don’t reach far enough to make contact. :person_facepalming:
It’s 2 AM and I’m far too tired to solder the carriers or more cells. :cry:

I will say the BLF GT is short compared to the TRJ-19 and TRJ-20, but the head is HUGE.
I need a handle for this thing, I was starting to get a cramped hand holding for a short bit. That said, I wish I could get an extended tube and use 3x battery carriers! :smiling_imp: