[PART 1] Official BLF GT Group Buy thread. Group buy officially closed! Lights shipping.

[NikolaS]

Great news TA, some picture for comparison would be nice

[Texas_Ace]

@I_like_lamb

One Question and One request:

What colour temperature will the emmiter be?

Also, can anybody with a GT post a picture with it next to the Q8, just so I can have a rough idea of how they compare in terms of size?

Thanks !

I have a bunch of pictures in this thread comparing it to other lights: I present you with Giggles, the most hardcore BLF thrower in the World.

[Texas_Ace]

@Tom E

The 223 uA parasitic drain sounds a little high. DEL measured it early on without the LED’s and didn’t think it was so bad. Big difference is where/how it was measured. If measured at the batteries, than it’s 223 uA at ~16.8V, which is very high.

Now I’m curious bout this - wish I could find DEL’s notes on it. I know the buck driver configuration has a higher parasitic drain but didn’t think it would be ~8X higher.

A Q8 with the LEDs ranges from 130 uA down to 90 uA, depending on the LED resistors, but that’s at ~4.2V.

The drain is actually right in line with what I would expect. The LM3409 uses a fair amount of parasitic power. The prior drivers tested out at around 140-150ua according to these posts, I got similar results in my tests IIRC.

[PART 1] Official BLF GT Group Buy thread. Group buy officially closed! Lights shipping.

The Miller requested that I give a little detail on the driver that we are putting together for this light. The XHP35 emitter, together with the 4S cell arrangement, presents some opportunities and challenges. On the one hand DD drivers are out - too easy to kill the emitter. 7135s are out - voltages are too high. On the other hand the 1-4 V voltage differential between the cells and the emitter (and the relatively low current) makes a buck driver ideal and relatively easy to implement. The boa…

[PART 1] Official BLF GT Group Buy thread. Group buy officially closed! Lights shipping.

As The Miller mentioned, the prototype driver is built and mostly tested. It is running a tweaked version of Tom’s NarsilM and it has been performing pretty well. Some numbers: Switching frequency is at 800 kHz with the selected components and at 16.8 V input. 100% output is 2.25 A, but this easily adjusted by changing Rsense. Aim is to have >= 2.5 A stock. Everything is running cool. ‘Hottest’ components are the buck chip and 100 mohm sense resistor, and both have a Trise of barely 20 C. Eff…

So that is only around 75ua for the LED’s and they have to drop a lot of voltage to get there, so everything lines up with what I would expect.

I would not complain about them being a bit brighter but it takes 4x as much current then normal (due to 4x the voltage) to make them brighter, so not sure it would be worth it.

[Texas_Ace]

@cccpull

@Texas_Ace

@djozz

I hope for clear weather and some spare time in the evening for TA to measure a proper throw-number

With a storm moving through and supposed to linger for the next several days, it doesn’t look good.

Although even without a storm, I live in one of the top 10 (think it is #4 last I checked) most humid cities in the USA. So there is not really such a thing as a dry night around here lol. We consider dry anything under 50% humidity.

Right now it is 50 degrees outside and 61% humidity as an example. Last week it was 90f and 80% humidity so it feels great right now.

That is why my beamshots look so vibrant, it is not a trick of the camera, it really looks like that, the refraction of the light is extreme.

Wow, at 50% humidity we get nose bleeds from the arid weather. We’re happy at under 70, at the moment it’s 80 degrees at 81 humidity, ant it was 95% humidity an hour ago.

LOL, I know the feeling. It is 60% humidity right now but it feels so dang dry. Most of the summer was spent with 80-90% humidity and 95f+ temps INSIDE the house and we didn’t have AC for any of it (well excluding a small window unit in the bedrooms so we could actually sleep at night). This was a fun summer lol.

[Texas_Ace]

@NikolaS

Great news TA, some picture for comparison would be nice

Yeah, I will try to get some shots later, I should at least be able to get a whitewall shot.

[Texas_Ace]

Some beamshots in the tent to show the tint.

[Tom_E]

Wow, 4000K has always been my favorite tint going back to XM-L2's, maybe XM-L's, not sure. But that one seems to have no hint of yellow at all.

I've had various tints in mods, intentionally, and every time I'd compare, the "5X" would be my favorite. 5B1's or 5D1/2/3's are real nice. Dropping into the warm ranges wasn't my thing.

The 5D2 IOS sold way back was highly regarded: https://budgetlightforum.com/t/-/22306

[Precision777]

Thanks TA for all the updates…… Looking forward to the Beamshots humidity or not!

[Texas_Ace]

I agree, I really like the 5A/5D tints myself. If I have to guess this one would be between a 5A and 4D. It has a hint of yellow if you turn the brightness down.

At full power the hotspot is so concentrated that it just looks like a small sun.

I can’t wait to see it at night, the warmer tints really work better in throwers. Thats why old incandescents throw so well even with so little output.

[renegade87]

Is there where you ask to be put on the list? If so sign me up please.

[Theodore41]

@Texas_Ace

@PVCC

@Texas_Ace

Thanks a lot for your detailed answers!

- I thought the chosen XHP35 HI was CW since CW is usually higher output (maybe I’m wrong, I’m not deep in this field)

- Thanks for the advice on the batteries. No worries, I understood the “official” recommendation now

- BTW, I usually use a Neodimiun super strong very “small coin” magnet that has Nickel coating, instead of solder blob. Did you try it?

Thanks a lot once again!

In older days you could get much higher bins in CW then neutral white tints. This is not the case anymore with the highest or 1 bin lower then highest usually being found all the way down to 4000-5000k.

So now days you really do not gain anything by going with CW in the real world.

People still think that CW produce higher outputs but that is mostly due to the cheap meters we use to measure flashlights. They are biased towards cool white light and will ready CW emitters as higher output as an equal bin NW emitter. This is just a reading error in most cases though, the bins in the data sheet much be correct or they would be sued.

So if you get different readings most of that is just a reading error in the meter.

To the human eye it is the other way around, you can see much better and much further with a NW or even WW emitter in the real world. This is well known, it is the same reason the sky is blue. Blue light is refracted in the air much easier then warmer tones.

So with a cool white LED you will see the beam like a light saber but that causes the intensity to drop much faster and the throw to be reduced in the real world.

Neutral white does not refract as easily so in the real world you can see further.

I have posted before my experiences with this that made me a whole hearted convert to NW.

Rayleigh law of light scattering.

[istrayli]

I would like to be put on the list to buy one of these please.

[Hovsky]

This is financially irresponsible…please add me.

[NikolaS]

@Hovsky

This is financially irresponsible…please add me.

Wow Hovsky first post since 2013 , and you said it right !!!

Totally irresponsible but so irresistible !

[NikolaS]

Is that the first emitter you checked, on the pictures above and making 2600 lumens on 2,5A.

If so ,I am impressed with tint and performance, reminding me to XM-L2 4D Fasttech used to have couple years ago

[Texas_Ace]

@NikolaS

Is that the first emitter you checked, on the pictures above and making 2600 lumens on 2,5A.

If so ,I am impressed with tint and performance, reminding me to XM-L2 4D Fasttech used to have couple years ago

Yes, the other one is in Giggles V2 now. It is very impressive, the highest output XHP35 HI I have tested so far IIRC.

I actually swapped my 1405 from a 3C E2 to the NW D4 and it looks WAY better now. I love it.

Can’t wait for night.

[johny723]

I thought the first prototype was good and ready for production, but this V2 seems to be virtually perfect. I doubt it can get even better at 111 $.
BTW, have you tried an XHP 70.2 in the BLF GT?

[Texas_Ace]

@johny723

BTW, have you tried an XHP 70.2 in the BLF GT?

Not an xhp70.2 yet, still waiting get my hands on one.

There may or may not be an old xhp70 in close proximity to the V2 prototype though. Although I have a feeling it will have a donut hole, so the xhp70.2 would be needed for best performance.

[CodyWolfeMusic]

Thanks for the cw and nw detailed explanation. I was going to get a TN-42 but once I saw your light was better I got in on it. I did a lot of research because Thrunite gave you an option. CW or NW, I was wondering why you guys chose NW. It’s good you explained to everyone why you think its better. Looking forward to trying it out. Never had a NW light before.

[Texas_Ace]

@CodyWolfeMusic

Thanks for the cw and nw detailed explanation. I was going to get a TN-42 but once I saw your light was better I got in on it. I did a lot of research because Thrunite gave you an option. CW or NW, I was wondering why you guys chose NW. It’s good you explained to everyone why you think its better. Looking forward to trying it out. Never had a NW light before.

Once you go NW you never go back.

You then move forward into high CRI NW.

I am rather picky, neutral white is no longer good enough, I need high CRI and will gladly give up lumens to reach it in many cases. It just look so much better and you can actually see what you are looking at.

I figure I will repost my story of what turned me onto NW again in condensed form.

I had both a thorfire S70 with the CW stock emitter and a convoy L6 with the NW 3A emitter. I modded both of them with a TA driver and they were both making around 6k lumens. The thorfire was about 10% higher in both lumens and throw when tested on the meter.

I took them out with the family and was testing them on a bridge over a creek. First I turned on the S70 and it was an impressive beam, lit up everything bright and we thought it was really impressive.

That is until I turned on the L6, instantly everyone unanimously liked it more by a wide margin. The beam was more pleasing to look at, the colors were far more life like and what really shocked me was that it actually seemed both brighter and it easily threw further. I expected exactly the oppisote result so it shocked me.

With the S70 we could just make out the far bank of the creek.

With the L6 we could easily see the rocks, bushes and even the frogs jumping into the water.

I was so shocked that as soon as I got home I checked the batteries in both of them and re-tested both lights. Sure enough same results as before, the batteries were about the same voltage and the S70 still was about 10% higher on the meter then the L6.

After that I ditched CW altogether and looked at lumens completely differently. Ever since I have been focusing on high CRI NW LES’s even if I don’t get as many lumens and never looked back.

People that see my lights always comment on how good everything looks and wounder what kind of light it is since they are used to seeing CW LED flashlights.

The moral to the store is that paper numbers don’t tell the whole story but then that is the case for many things.