(prototype) the GT Mini

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ToyKeeper
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About the earlier discussion of lumens…

There are several different units in common use, and all of them are called a “lumen”:

  • The main one is the ANSI standard lumen. Maukka has calibrated equipment which uses this scale. I think djozz may be using it too.
  • The most common on BLF is the Zebralight/cpfselfbuilt lumen scale. It usually runs about 40% higher than ANSI lumens, so a 100-ANSI-lumen light will typically read about 140 lumens on a zebraselfbuilt scale. I think this is what I’ve been using, since I calibrated my light box to match selfbuilt’s numbers and Zebralight’s numbers. I think it’s also what DB Custom uses, and several of the other modders here on BLF.
  • Texas_Ace light tube lumens. I hear these may be higher still, but I don’t know the details.
  • Every other person’s home-calibrated light box. These all differ from each other, so the numbers are only really comparable to other measurements by that same person.

Additionally, there are other factors making this more complicated:

  • Emitter lumens vs OTF (out the front) lumens. A bare emitter measures higher than one housed inside a flashlight with various optics. I think this may have been the origin of the Zebraselfbuilt scale, in part. The OTF Zebra lumens are often pretty close to the ANSI OTF lumens, at least in some lights.
  • Measurement timing. Numbers measured at start are usually higher than measured at the ANSI-standard timing of 30 seconds.
  • Sag. Output sags over time in a lot of lights. ANSI runtimes technically go until the light sags to 10%, IIRC, but this value is misleading. 3 hours at 1000 lumens may actually be 3 minutes at 1000 lumens and then 2h at 200 lumens, then 57 minutes at 101 lumens.
  • “Chinese lumens / Ultrafire lumens”. Marketing people like to make up numbers to try to make lights sell better, especially on cheap items. Often times they’ll take the emitter’s maximum rated ANSI emitter lumen output and claim the product does two or three times as much. This number has very little relation to actual real-world performance.

From what I can tell, the GT-Mini will probably make about 1200 OTF Zebra lumens, slightly less than the Emisar D1S’s 1300-1350 OTF Zebra lumens. The number is probably lower on an ANSI OTF scale though. And it’s almost certainly not 2000, unless we count Ultrafire lumens… in which case it’d probably be about 2500 to 4000.

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Since I have plans to mod my GT mini, I’ll pull the driver and send it to you when I get the light TK…. Wink

ToyKeeper
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DB Custom wrote:
Since I have plans to mod my GT mini, I’ll pull the driver and send it to you when I get the light TK…. Wink

It may be totally unnecessary. The manual indicates it’s running NarsilM 1.2, I think. It might be totally unmodified from what’s on the big GT.

If that’s the case, everything might “just work”. So, definitely try it first… Also, I may be travelling for a while and may not be able to receive packages or get much done. So I hope things will work as-is without any changes.

steel_1024
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Which one do you like more?

Edited:Link…..
http://budgetlightforum.com/node/61431

Sorry for my poor english.

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Order placed. Can’t wait to get mine!!

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ToyKeeper wrote:
About the earlier discussion of lumens…

There are several different units in common use, and all of them are called a “lumen”:

  • The main one is the ANSI standard lumen. Maukka has calibrated equipment which uses this scale. I think djozz may be using it too.
  • The most common on BLF is the Zebralight/cpfselfbuilt lumen scale. It usually runs about 40% higher than ANSI lumens, so a 100-ANSI-lumen light will typically read about 140 lumens on a zebraselfbuilt scale. I think this is what I’ve been using, since I calibrated my light box to match selfbuilt’s numbers and Zebralight’s numbers. I think it’s also what DB Custom uses, and several of the other modders here on BLF.
  • Texas_Ace light tube lumens. I hear these may be higher still, but I don’t know the details.
  • Every other person’s home-calibrated light box. These all differ from each other, so the numbers are only really comparable to other measurements by that same person.

I’m not too familiar with the Zebralight/cpfselfbuilt lumen scale.

DB Custom, Robo819, Richard at MTN and Tom E use the Manxbuggy1’s lumen tubes which I think are only 10% to 15% higher than Maukka’s readings. (certain throwy lights might be a bit higher due to no diffusers in the design)

Texas_Ace’s personal lumen tube did read a bit higher than the ones above. About 30% higher than Maukka’s. After getting some reference lights shipped to Maukka to test, he has adjusted his tube down to match. All of the Texas_Ace Lumen Tubes he sold have also been adjusted down to match. Officially he still states about a plus or minus 7% range on them.

Maukka has also decided to sell a small batch of carefully measured and documented lights for anyone who wishes to calibrate their own integrating sphere/lumen tube.

I think the bottom line is if you want exact lumen numbers your gonna have to buy a $10,000 professional integrating sphere.

If you don’t want to spend that much money, you can ship a certain light to be tested by someone who does have one. This is slow and can get very expensive the more lights that need to be sent.

The next cheapest method is to just build your own device then calibrate it with a certified light from someone like Maukka.

The cheapest and probably best way is to just buy a Texas_Ace Lumen tube. It’s already calibrated plus is very well thought out. Plus you get lumen readings right off the lux meter with no math involved.

The two homemade options are always going to have bigger tolerances, but they are much more practical and cheaper.

Texas Ace Lumen Tube calibrated with Maukka lights

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djozz
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As an addition to ToyKeppers post above:

The djozz-lumen is the output of my Sunwayman D40A on high setting divided by 550. It was established a few years ago and I keep it as my standard because it is consistent over all my measurements, and with the D40A always available it is easy to maintain.

Since then I have learned that the djozz-lumen is likely higher than the real lumen, some comparisons that I did in Germany with flashlights measured before in the LedLenser sphere, and an exchange of 2 different flashlights with maukka suggest that the djozz-lumen is on average around 9% high. But compared to maukka’s setup a high CRI 4000K flashlight (the 348 light that maukka is selling now for calibration) produced a bigger difference (11%) than a 5000K 70CRI Nitecore P12 (7%), so despite using a very high quality well V-lambda corrected luxmeter I have a spectrum sensitivity difference with maukka as well.

JasonWW
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djozz wrote:
As an addition to ToyKeppers post above:

The djozz-lumen is the output of my Sunwayman D40A on high setting divided by 550. It was established a few years ago and I keep it as my standard because it is consistent over all my measurements, and with the D40A always available it is easy to maintain.

Since then I have learned that the djozz-lumen is likely higher than the real lumen, some comparisons that I did in Germany with flashlights measured before in the LedLenser sphere, and an exchange of 2 different flashlights with maukka suggest that the djozz-lumen is on average around 9% high. But compared to maukka’s setup a high CRI 4000K flashlight (the 348 light that maukka is selling now for calibration) produced a bigger difference (11%) than a 5000K 70CRI Nitecore P12 (7%), so despite using a very high quality well V-lambda corrected luxmeter I have a spectrum sensitivity difference with maukka as well.


And lots of people think it’s easy to measure lumens. Just buy a lumen meter on ebay, they say. Facepalm It’s funny.

I think the general consensus is that warmer tints do read a bit lower in lux compared to cooler tints, but this is still debated. I try not to think too much about it. It makes my head hurt. Lol

Texas Ace Lumen Tube calibrated with Maukka lights

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ToyKeeper
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I’ve considered buying a calibration source from maukka. Before doing that though, I’d need to build a more proper integrating sphere… and I’m not sure I care enough to do that.

So I have a very cheap and compact measurement device with calibration based on a couple Zebralight SC52s, selfbuilt’s reviews, and a few people who were publishing numbers on BLF a few years ago. And it almost certainly reads between 10% and 50% higher than an ANSI lumen.

The downside is that it’s known to be skewed. The upside is that it typically matches most manufacturers’ published specs pretty closely. But then, another downside is that, apparently, most manufacturers exaggerate. Sad

Also, since what I’m using is small, it can’t handle more than about 2500 lm without some sort of attenuator. So I get to mess with neutral density filters while measuring bright lights.

But back on topic, it’ll be interesting to see how the GT-Mini performs. It seems like it’ll be a D1S with a nicer host, flatter but slightly lower output, and a more full-featured UI.

JasonWW
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ToyKeeper wrote:
I’ve considered buying a calibration source from maukka. Before doing that though, I’d need to build a more proper integrating sphere… and I’m not sure I care enough to do that.

Have you considered getting a TA Lumen Tube? When you add up the time and parts cost to build a device that properly diffuses both floody and throwy lights plus an additional $75 for the calibration lights, you actually come out ahead just buying his for about $150 shipped. It’s well thought out and very easy to use. You don’t even need a calculator. Wink

Texas Ace Lumen Tube calibrated with Maukka lights

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ToyKeeper
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JasonWW wrote:
You don’t even need a calculator. Wink

You can have my HP48GX when you pry it from my cold, dead hands.

Well, okay, actually it pretty much just sits in a box and I use Python to do calculations. But still.

lionheart_2281
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Sooooooooooooo much better

mortuus
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yes that looks alot better, but what about the frontal below the button what will be there?

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mortuus wrote:
yes that looks alot better, but what about the frontal below the button what will be there?

Probably nothing.

The new font is better than the old one, but I still wish the logo was smaller.

Texas Ace Lumen Tube calibrated with Maukka lights

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mortuus
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well i dont see why not it cant have the logo atleast ? but a step in the right direction tho.

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Do we have an estimate on when the first units are supposed to start shipping? I kinda want to see beamshots of both tints before placing my order. I would have preferred a 5000k option, so I’m not sure which one will be closer to my preferences.

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Should be easy enough to change if the tint doesn’t suit you, I just ordered some Samsung LH351D in 5000K at 80CRI for less than $2 apiece bare.

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Ordered a NW version with additional short tube, and 30Q since I only have 2 of these

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Delta_V wrote:
Do we have an estimate on when the first units are supposed to start shipping? I kinda want to see beamshots of both tints before placing my order. I would have preferred a 5000k option, so I’m not sure which one will be closer to my preferences.

if i remember correct, early next week for us that buy the light in here.

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that's correct

 

the groupbuy people had this one week presale so they can Shipp as soon as possible  

 

 

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Ordered 1 Mini GT with 18350/18350 Tube.

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Just filled out the form, is the GB still on Martin?

About the driver: is it sure a buck driver, as mentioned in this thread? I can’t believe they went for that, the voltage difference between a 18650 cell and a XP-L Hi is so small that it will only regulate current a little in the first few minutes, I’d choose for simple cheap lineair and have that extra boost of direct drive in those minutes. I’m curious about the first pictures of the driver.

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Looking at Texas Ace’s measurements, the XP-L HI has a V_f of around 3.7V @ 4.5A.

So accounting for the voltage sag under load, a high drain cell should stay in the regulated region for slightly less than half of its capacity on turbo.

The other big advantage of a regulated buck driver over a FET is improved efficiency in the intermediate modes. So it should be able to produce noticeably better runtimes at 60-80% of max than the Emisar D1S. I’ll gladly take that over an extra 100 turbo lumens that won’t be noticeable by the eye anyway.

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I answer todays requests tonight 

 

will also add a Diffusor and a surprise Wink 

 

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++

Delta_V wrote:
Looking at Texas Ace’s measurements, the XP-L HI has a V_f of around 3.7V @ 4.5A.

So accounting for the voltage sag under load, a high drain cell should stay in the regulated region for slightly less than half of its capacity on turbo.

The other big advantage of a regulated buck driver over a FET is improved efficiency in the intermediate modes. So it should be able to produce noticeably better runtimes at 60-80% of max than the Emisar D1S. I’ll gladly take that over an extra 100 turbo lumens that won’t be noticeable by the eye anyway.


Regulated about half of its capacity, is this correct? A 30Q at 5A starts between 3.9 and 4 V, at 8 minutes it drops below 3.8V, at half capacity it is at 3.6V. Between cell and led there is always a voltage drop caused by body, springs and wiring, if you get a 0.2V drop (at 5A current), that is very good, in that case the springs are already bypassed. So the battery voltage comes very soon very close to the led voltage for 5A. Further from what I understand about buck drivers, they need a minimum overhead voltage, a value that I can find is a minimum 0.5V difference needed to function. So I do not see a buck driver doing a thing here.

But I must confess that my knowledge about basic calculations is better than my knowledge about drivers…

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ToyKeeper wrote:
The most common on BLF is the Zebralight/cpfselfbuilt lumen scale. It usually runs about 40% higher than ANSI lumens, so a 100-ANSI-lumen light will typically read about 140 lumens on a zebraselfbuilt scale. I think this is what I’ve been using, since I calibrated my light box to match selfbuilt’s numbers and Zebralight’s numbers. I think it’s also what DB Custom uses, and several of the other modders here on BLF.

Wow. 40%. If that is true then I am going to have to rethink a lot about manufactures numbers. I was under the impression (perhaps falsely) that the zebralight calibration was one of the more premuim methods. It was for that reason that I assumed Acebeam L16, X45, X80, all of my olights and many other top brands were within about a 10% margin of error from the truth. Most often with those brands I would get just under or just over the rated output.

I have ordered a set of Maukkas lights and could hardly be more excited!
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About the GT MINI. I get why 18650 was the choice. That said if 20700/21700 options come available I would be crazy over that.

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vestureofblood wrote:
About the GT MINI. I get why 18650 was the choice. That said if 20700/21700 options come available I would be crazy over that.

Absolutely! I’d love to see this light with a 21700 tube.

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Are all physical ratios the same as the GT (i.e. a scale model) or does it just look roughly like the GT?

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I’d love to see it with a 26650 tube. It’d be a good place to store one of my Littokala’s….. Wink

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