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

GT user manual (draft 12) in text format (for Google Translate)

Thank you for supporting this BLF community project. The GT was designed by BLF, for BLF, and brought to life by top-tier manufacturer Lumintop. We trust it will serve you well in whatever your endeavors might be!
- the BLF GT project team

Safety precautions

  • Use only reputable 18650 cells of known origin. Protected type cells, based on Samsung, Panasonic/Sanyo, Sony or LG cells, are recommended.
  • Use a reliable battery charger. Never over-charge or over-discharge cells.
  • Cells are used in series, not parallel. It is therefore important that all cells are identical: Same make, model, capacity, age, used cycles, and furthermore charged to the same level.
  • Remove and recharge cells when the low voltage indication is given by the GT (repeated step-downs in light level and eventual shutdown of the light).
  • The extraordinary energy density that 18650 cells offers also means that hazardous conditions are created when a cell is short-circuited or damaged. Always treat cells with respect and properly dispose of damaged cells.
  • The GT is a very high-intensity flashlight. Do not point the GT directly at a person, animal, moving vehicles or flammable materials.
  • When running at higher output levels the head of the GT will slowly heat. This is normal. In warmer ambient conditions this temperature may exceed 60ºC, so please take the necessary precautions when handling the GT.

Quick start

  • Load the cell cradles with four 18650 cells each. Note that the cradles require button-top type cells. The GT is designed to work with either or both cell cradles populated. Take care to observe the correct polarity for each cell.
  • Unscrew the tail-cap and insert both cradles. Again take care with the polarity: Arrows on the cradle rods must point towards the head of the GT. If populating only one cradle we recommend placing it towards the rear, so that the GT balances better in the hand.
  • Screw the tail-cap back. The GT will flash twice when electrical contact is made. Continue to tighten the tail-cap to a gentle stop. Do not over-tighten.
  • All functions are performed using the single side button. Note that pressing this button continuously for more than 8 s enters the UI configuration settings (indicated by the light blinking). If this is done inadvertently, exit the configuration settings by simply releasing the button briefly then pressing it again continuously for about 4 s until all the resulting blinks stops.
  • The GT comes factory-set to use the RAMPING UI: From OFF, press&hold the side button. The light output will ramp up from a very low level to full power. Release the button when the required light level is reached. (The full ramp takes about 3 s.) Use a single-click at any time to turn the GT OFF. Please see below for further details.
  • There is a very small drain on the battery while OFF. This should not be of any concern, but we recommend removing the cells (or partially loosening the tail-cap) if the GT will not be used for several months.
  • By default the button back-light is illuminated while the GT is OFF. This is normal and is done to easily locate the button in a dark environment. Turning the GT ON, then OFF, in rapid succession, disables the back-light until the next use. This is also normal.
  • For the complete user manual and any questions you might have about your GT, please visit the GT support thread on BLF. The link is on the last page of this manual.

Default UI: Smooth ramping

This feature-rich UI provides for smooth ramping of the light output between 0 and 80, with an easily-accessible 100 TURBO mode.

  • Turn the GT ON:
    single-click the button, GT turns ON using the previously used light output level
  • Ramp light level:
    press&hold button
  • Reverse ramp:
    while ramping in one direction, release button briefly and press&hold again
  • Instant TURBO:
    double-click
  • Turn the GT OFF:
    single-click
  • MOON mode:
    from OFF: press the button and release as soon as the GT turns on
  • Strobes:
    double-click for TURBO, and then double-click again
    (Use single-clicks to cycle forward through the different types of strobes, but you have to be quick: If resting on a strobe longer than 1.2 s it locks in and the next single-click is OFF. Press&hold at any time to cycle backwards through the strobes.)
    Battery status: triple-click (4 blinks, a short pause, then 1 blink would indicate 4.1 V average per cell, for example)
  • Electronic lock-out:
    four clicks to disable the GT, same to re-enable the GT
  • MOMENTARY mode:
    five clicks (loosen and re-tighten the tail-cap to return to normal operation)
  • Factory reset:
    triple-click (battery status mode), then double-click (driver temperature mode), double-click again (firmware version mode), then press&hold for about 2 s. Four blinks confirm a successful reset.

Alternative UI: Mode-sets

The GT is factory-set to operate using the contemporary RAMPING user interface, as described in the previous section. However, the GT can also be operated using a more conventional MODE-SET style user interface. (See next section for detail on how to set UI options).
Using the MODE-SET UI the output does not ramp, it steps from one mode to the next using single-clicks.

  • Turn the GT ON:
    single-click
  • Next mode:
    single-click before the current mode ‘locks in’ (1.2 s)
  • Previous mode:
    press&hold
  • Last mode [100%]:
    from OFF: press&hold
  • Turn the GT OFF:
    single-click button, after resting on a mode more than 1.2 s (mode locked in)
  • Strobes:
    press&hold
    (Use single-clicks to cycle forward through the different types of strobes, but you have to be quick: If resting on a strobe longer than 1.2 s it locks in and the next single-click is OFF. Press&hold at any time to cycle backwards through the strobes.)
    Battery status: from OFF: single-click followed by press&hold (4 blinks, a short pause, then 1 blink would indicate 4.1 V average per cell, for example)
  • Electronic lock-out: from OFF: double-click followed by press&hold, same to re-enable the GT
  • Factory reset: from OFF, single-click followed by a press&hold (battery status mode), then double-click (driver temperature mode), double-click again (firmware version mode), then press&hold for about 2 s. Four blinks confirm a successful reset.

Advanced operation

By default the GT firmware is set to suit most users and applications, but several settings are user-configurable. To enter the configuration settings, press&hold the button for about 8 s (3 s if in the MODE-SET UI), do not release until a double flash followed by a single blink is seen. The single blink is the prompt for the first setting. Click the button as many times as required for that setting, or leave the setting alone and simply wait for the next double flash, this time followed by two blinks, indicating that we are now at setting #2, etc.
The GT confirms each click with a blink. A press&hold skips to the next setting. A continuous press exits the setup menu completely. Four blinks indicate that the setup is completed.
The available settings differ, depending if the GT is currently set to the RAMPING UI or the MODE-SET UI. Note that changing setting 1 flips to the other UI and immediately kicks you into the table for that UI:

RAMPING user interface settings
Setting     Function        Clicks
1       User interface      1: MODE-SET 2: RAMPING [default]
2       MOON level      1-7 [default 3] 
3       Auto step-down      1: Disable 2: Temperature [default]** 
                    3: Timed, requires another 1-6 clicks for 60s/90s/2m/3m/5m/7m respectively
4       Strobes         1: Disable 2: Strobe 1 only 3: All strobes [default]

MODE-SET user interface settings
Setting     Function        Clicks
1       User interface      1: MODE-SET 2: RAMPING [default]
2       Mode-set        1-12 [default 4]
3       MOON mode       1: Disable 2: Enable [default]
4       Mode order      1: Low to high [default] 2: High to low
5       Mode memory     1: Disable [default] 2: Enable
6       MOON level      1-7 [default 3]
7       Auto step-down      1: Disable 2: Temperature [default]**
                    3: Timed, requires another 1-6 clicks for 60s/90s/2m/3m/5m/7m respectively
8       Strobes         1: Disable 2: Strobe 1 only 3: All strobes [default]

If [temperature] is selected for auto step-down, the GT goes to 100% output. Leave the GT to heat to the desired limit, and then click to set that temperature as the trip point (the GT is huge, so this can take 20 minutes or longer, use fresh cells for this). Or click within 5 s to keep previous setting.

The mode-sets have been selected to suit a high-power thrower like the GT:

Mode-set no.    Modes [% of light]
        1   2   3   4   5   6
Sets 1 to 6:  100% = 2.0 A LED drive
1       100                 
2       25  100             
3       11  33  100         
4       12.5    25  50  100 [default]
5*      1   7   22  52  100 
6*      1   5   15  32  60  100
Sets 7 to 12:  100% = 2.5 A LED drive
7       100                 
8       25  100             
9       11  33  100         
10      12.5    25  50  100     
11*     1   7   22  52  100 
12*     1   5   15  32  60  100

Modes in sets 5, 6, 11 and 12 are equally-spaced on a cube-root curve (considered an ideal mode-spacing by many).
Note that MOON mode is enabled by default, adding one extra mode (mode 0) to the above.

Pre-programmed strobes:

Strobe  Type
1   16 Hz
2   Police strobe (dual frequency)
3   Biking (low light with hi-vis stutter)
4   2 s beacon
5   10 s beacon

Additional UI settings are available to control the button back-light. While in the battery check mode, press&hold the button. A double flash followed by a single blink is again the prompt for the first setting:

Advanced UI settings
Setting Function                Clicks
1   Button LED on while GT OFF      1: Disable 2: Enable [default]
2   Battery level blinks on button LED only 1: Disable [default] 2: Enable
3   Button LED              1: Disable 2: Enable [default]

Specifications

  • Emitter:
    12 V Cree XHP35 High Intensity, neutral white, mounted on copper DTP MCPCB
    Flux: >2000 lm
  • Intensity:
    >1 Mcd (ANSI throw >2000 m)
  • Firmware:
    Tom E’s open-source NarsilM v1.2
  • User interface:
    • By default the GT is set to use the very intuitive Narsil smooth RAMPING UI. Instant access to a 2.5 A TURBO mode is also provided.
    • A more conventional discrete level MODE-SET UI is available as an alternative. Any one of 12 pre-defined mode-sets can be selected.
    • MOMENTARY mode is useful for signaling purposes or rapidly/briefly lighting up targets.
  • Battery:
    Four or eight button-top 18650 cells (4S1P or 4S2P). Protected cells are recommended. Cells are not included.
  • Driver:
    35 W, 2.5 A regulated buck driver with conversion efficiency that exceeds 90%. Parasitic drain while OFF is ~150 μA (~250 μA with button back-light on).
  • Reflector:
    118 mm ID, aluminum, smooth finish
  • Lens:
    Glass with anti-reflective coating
  • Body:
    Aluminum with Type III hard-coat anodizing
  • Tripod socket:
    Standard 1/4 inch threaded (1/4-20 UNC)
  • Button:
    Tactile with back-lit rubber boot
  • Ingress rating:
    Equivalent to IP65, do not immerse in liquids
  • Weight:
    Approximately 1.8 kg without cells
  • Dimensions:
    135 mm Ø head x 315 mm length

GT support thread:

GT main thread:

[Edit: 2018-01-11: Added the two thread links]

So what does the team do on mars?

Accessories for the GT

Thank you joechina for this compilation:

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Please don’t post it if you subscribed.

Please keep this thread clear of any ‘offtopic’ chatter.

Thank you
:wink: :+1: :+1:

Got mine today. My switch LEDs are different brightness levels like someone mentioned before. Not sure if it bothers me though. Anyone else have the same issue?

FAQ: How can I get a BLF GT?

  • Post in the main GT thread saying that you want one (or more). Then wait for a private message with further instructions. It may take a few weeks before you can make the purchase, because production is slow.

FAQ: Can I get more throw if I drive the emitter harder?

  • No, not really. It’s already driven at 2.5A, which is just shy of the peak for the GT’s emitter. There’s very little to be gained from giving it more power; it’ll mostly just produce more heat.

FAQ: Why is my lux meter showing me less than 1.2 Mcd for the GT?

  • Could be caused by several things…
    • Lux meters usually read higher for cool white lights, so the GT’s warmer tint could be tricking the meter. This doesn’t mean it won’t throw as well as intended, just that the meter isn’t very good as measuring it.
    • The beam doesn’t fully collimate until ~20+ meters, so it may be necessary to increase the distance between the light and the meter for a good measurement.
    • The light might be running at 2.0A instead of 2.5A. Be sure to take measurements on turbo (which is above the normal output modes; double-click to access turbo).

FAQ: How can I mod it to increase throw?

  • Try an Oslon Black Flat for maximum throw. The hotspot will be tiny though, and the driver may need to be replaced or modified (TBD).

FAQ: How can I mod it to increase lumens?

  • Try a 12V XHP50, XHP50.2, XHP70, or XHP70.2. It will decrease throw though, and the driver’s sense resistor should be changed to increase power to ~5A. Bigger hotspot, more lumens, less lux. Texas_Ace tried it and says the result is nice. Using 8 cells is strongly recommended for this.

FAQ: My tailcap ring doesn’t want to spin. Help?

  • There may be a pinched or insufficiently-lubed O-ring inside. If you remove the Lumintop sticker inside the tailcap, the parts should unscrew (reverse-threaded), and then you should be able to check and lube the O-rings.

Thanks TK! Done and done into post 4.

There’s another question I’ve been asked a few times, but it’d probably be out of place in the main list…

FAQ: When will other firmware be available?

  • As soon as I get a GT. I have no idea when that will be, but it should only take a few hours after I get hardware to test on.

Google Translate does not translate PDF files
Any solution for non-English speakers?

EDIT

Solved. … BLF GT official support thread [FAQ updated 11 Jan 2018] - #5 by Team-Giggles
Thank you very much.

Please see if post 5 is useful. (Still need to somehow add the various tables to it.)

Either I have the wrong switch cover, or my LEDs are so dim that you can’t tell they’re working unless you’re in a dark room or at night, but I’m beginning to think it’s the LEDs

Hopefully TA can chime in, most of the team lights shipped with opaque button boots.

It is supposed to be very dim, as mentioned in the FAQ above. Two Three ways to have it brighter:

  • Change the boot to a clear one. The boot is 12 mm, not a common size unfortunately.
  • Change or stack the resistor controlling the back-light current (R8). Stock value is 33k for ~100 μA. Change to 15k or stack another 33k on top of the stock resistor to double the current. The resistor should be 0603 footprint, but a 0805 will fit as well. Note that this will take the parasitic drain from ~240 to ~340 μA.
  • Rewire the button LEDs in series and drop R8 accordingly.

Edit: For the mismatched LEDs, that can happen with LEDs wired in parallel. Still preferable to having one off-center LED I guess. It may also simply be the way the rubber boot is orientated. A simple hack here would be to rewire the LEDs in series and change R8 to 10k (MCU is running at 5 V on GT, so there is enough voltage to do this). Bonus, double brightness for same parasitic drain.

In post 5, specifications, emitter, could we add the details that it is a D4 bin and 4,000k color temp?

Also, I have been asked if the strobe modes are using the 2A, 2,000 lumen mode or the turbo 2.5A, 2,500 lumen mode. Does anyone know?

It seems a handful of black boot slipped through to normal people as well. Neal is taking care of them on a case by case basis.

You are also spot on with the rest of the details.

Post 5 is a verbatim copy of the printed manual so it should stay as is. No problem to add the bin info to the FAQ though.

For the strobes, these are at 2.5 A. This is from the source code:

void Strobe(byte ontime, byte offtime)
{
    FET_PWM_LVL = 255;
#ifdef GT_BUCK
    ONE7135_PWM_LVL = 255;  //  for GT-buck
    _delay_ms(ontime);
    ONE7135_PWM_LVL = 0;        //  for GT-buck
#else   
    _delay_ms(ontime);
    FET_PWM_LVL = 0;
#endif
    _delay_ms(offtime);
}

Basically the buck chip is set to full power in the first line and then alternatively enabled/disabled in the next three lines.

Is there a way to have the lighted switch stay on when the light is turned on? Having a lighted switch is just as helpful when you want to change output levels or turn the thing off as it is when you want to turn it on.

There’s no option for that. You’d have to manually run a new wire to keep it powered all the time, so you’d lose the “indicator” function. No big deal as I have two lights where the switch stays on all the time.