[PART 2] Official BLF GT Group Buy thread. Closed, but Public sales open!

Are you realy shure that all dies on the LED are ok an not like mine in the pictures above?

I checked my voltage and yours is higher than mine. I got 14.6v on high and 15.3v on turbo.

To check the amperage you would need to unsolder one of the LED wires and either extend one and use a clamp style ammeter or you could put a multimeter style ammeter inline with the two wires. The clamp style is usually more accurate. You should be seeing around 2 amp on High and 2.5 amp on Turbo.

Do you know how to measure the candela at 1 meter?

1 meter is not nearly enough for the GT, 10m is much better and makes the math easy as well.

Oh that’s s pulse modulated driver, isn’t it?

Texas_Ace - That’s a good idea. I will do 10m as requested. Here is the result of that test:
10m = 10.9 yards = 32.8ft. I got 10500 lux, (double click turbo) centered on the collector.
Does that sound correct?

Wieselflinkpro - Yes. I’m sure. If I put the light on moonlight, I can look at it, but I wish I had some welding glass, so I could look at it on Turbo.

JasonWW - Yes, I did de-solder one of the wires, and I double checked my meter was on DC. I have a Fluke 87v. But, like I said, that’s a pulse modulated driver, isn’t it? I’m not going to get an accurate reading unless I record it and measure the pulse widths, right? The duty cycle.

You misunderstand. We need to know the candela at 1 meter. To get this number we do the actual measurement at a longer distance (5m, 10m, etc…) then calculate it back to 1 meter. I was basically asking Longtom if he knew how to do these calculations.

Yes, that sounds spot on, that is 1Mcd which depending on the conditions is what I get out of mine as well.

Ah, Ok that makes more sense. I figured you knew that 1 meter was not enough.

Texas_Ace, (and everybody else)

ALL IS WELL! Thanks to everybody for the help, and for the lessons learned. Every time I come here, I learn something new. That’s what makes this forum so wonderful.

Well, Jason did the real work, I just repeated what he said lol.

TA, you can remove my name from the missing bag list. Neal refunded me since it never came. Thank you.

I’m not sure what you mean by “centered on the collector”.

I measure out my distance from the sensor on the wall to the emitter. I turn the light on turbo and then go to the wall and move my lux meter around in the hot spot to find the brightest part of it.

To calculate your 10,500 lux back to 1 meter you go 10500 x 10 x 10 = 1,050,000cd.
To find the throw distance to take 1,050,000 x 4 = 4,200,000. Then find the square root of that and you get 2,049 meters of throw or a bit over two kilometers.

This sounds right in line with other people’s measurements.

I’ve heard some people get slightly different results with the GT if they measure it at 15 or even 20 meters. It seems to depend on how the beam is focused.

You can also try measuring the TN42 at 10 meters and see if it’s around 6,500 lux. I think that’s what it should be close to.

Okay.

Also, I still have not heard anything from Neal or Leo about the Issues list. Does Leo exist? :slight_smile: I’ve never heard anything from him.

On this I have no idea. I would assume it would read normally. Some DMM just don’t read amperage accurately due to resistance in the leads and connectors. I always use a clamp style ammeter.

It means with the center of the hotspot of the beam centered directly onto the light collector (the sensor thingy) of the meter at the requested 10 meters.

No, that’s not such a good idea. The very center of the hot spot can sometimes be the dimmest area. Look at this pic of my L6 and you can see the center is definitely dimmer.

The GT at 10 meters might be a different story, but I would still move the sensor around to find the brightest part of the hot spot.

I have got 1700 lumen with the TA tube… it could have been around 2000 lumen if the light doesn’t escape from the opening…

So yea … blf gt is doing around 2000 ballpark.

Yea, of course. :slight_smile: I set the meter on “max hold” or whatever the setting is, and move the beam around the sensor. when I’m done, I can walk over and see what I did.

Is there anybody who still hasn’t managed to get their GT opened using the strap wrenches? I’ve used the rubber and the nylon strap ones but it always feels as though i were going to tear the strap instead, especially the rubber one. And the GT still won’t budge!

I’ve found that using max hold can give higher readings than normal. I turn the light on turbo, then wait about 30 seconds or so for the output to drop and stabilize. While waiting is when I find the brightest part of the beam. I move the sensor back and forth around that “brightest” area and see what the highest average reading is.

Then again, my lux readings always seem lower than others. So IDK. :slight_smile:

Just a few days ago Kawiboy1428 reported at least two GT’s where the bezel threads were not cut just right or something. I dont think these were group buy lights.

From Kawiboy1428