FW3A, a TLF/BLF EDC flashlight - SST-20 available, coupon codes public

On high or lower modes? The Convoy and similar drivers have an odd quirk that causes poor regulation on lower modes.

I built my first Convoy recently using an 8x7135 Qlite driver - pretty similar to the Convoy driver, but I have STAR firmware on mine. Out of curiosity, I tested the regulation with a linear power supply. Mine held regulation at ~3 Amps until the input level dropped below 3.4V when driving a 2.8-2.9V rated 219C. It dropped to 50% of initial current draw at 3.15V.

Considering Nichiaā€™s datasheet shows the forward voltage is 3.4V at roughly that current level, this $5 driver seemed to have perfect regulation. There are caveats for voltage binning and the temperature dependence of Vf, but they donā€™t change the conclusion much.

Surprisingly, regulation was far worse on lower modes.

My 750 mA target (25%) mode fell out of regulation at 3.9V.
My 90 mA target (3%) mode was already out of regulation at 4.3V.

This wasnā€™t actually a surprise to me. I was looking for it specifically because when shopping for a driver, I noticed HKJ documented it over 4 years ago. He speculated based on oscilloscope data that the 7135 chips respond too slowly to the 16 kHz PWM to turn on fully when the duty cycle is low. Maukka measured similar when he did a more cursory output test of an S2+.

However, the D4 also uses a high frequency PWM for its 7135 chip, yet does not share this issue. I donā€™t know if it is due to the specific brand of 7135 used, a driver design issue, or if Toykeeper, TomE or others know a firmware trick to avoid it.

Please add me to the list (2)

All of the above. The FW3A uses a few methods to avoid that problem:

  • Chip brand: ā€œRaptor clawā€ 7135 chip chosen specifically for its activation speed, so it will perform well with short pulses. The low-mode problems are mostly seen on ā€œfailboatā€ 7135 chips.
  • Driver design: 1x7135 chip on its own channel, so it uses the 350mA Vf instead of the 3A Vf, and can thus regulate longer.
  • Firmware: Slower PWM frequency at the lowest levels, like moon, to improve stability and reduce voltage sensitivity. Also reduces total power draw significantly, so moon runs about 3X longer than it would at full speed. (the D4 doesnā€™t do this, but the FW3A does)

Soā€¦ regulation on this thing actually works pretty well.

Aha! Thanks for the reply. I spent far too much time researching this issue before I gave up trying to find answers and bought parts for my build.

I should have just created an account here earlier to ask, instead of digging through countless old threads.

But Iā€™m glad I mentioned it in this thread, because now I know the concern is already addressed in the FW3A.

Unfortunately, it seems there are a lot of drivers out there using the lower quality chips.

All this from a $30-$36 light? Outrageous!
This thread, (well, portions of it) should be required reading for all flashlight manufacturers.

ā€œWaddaya think, Joey? High, medium, low? Or low, medium, high?ā€
ā€œHowzabout medium, low, high?ā€
ā€œBrilliant! Weā€™ve got our UI,ā€¦ what else?ā€
ā€œWuddabout some flashy stuff?ā€
ā€œScope creep! Weā€™re done!ā€
(end scene)

Sign me up for 1, maybe 10 :slight_smile:

I know what you mean! Iā€™m leaning that way thinking of a couple extra for my kids.

Forfive me if this has been asked before, does FW3A will have PID for thermal control? Thanks :slight_smile:

ToyKeeper just said this a couple posts above.

So yes, it will increase brightness if the light is cooled down. I assume thatā€™s what your are asking.

Didnā€™t realize that post, mostly because i only took a quick glance of most posts here. :person_facepalming:
Anyway thank you.

Please add me to the list for one (1).

Body color is not very important to me, but I think the silvery color of the prototype looks nice, even if not quite like bare aluminum.

You probably donā€™t need to read every post, but ToyKeeper is one of the main FW3A team members who actually posts updares on this project. Itā€™s always good to read her posts, even if the techno stuff goes over your head. Lol

FW3A Team
Fritz15: Design
Tommy TLF: General TLF communication
DEL: Driver
Tom E: Firmware (originally), driver
ToyKeeper: Firmware / UI, BLF gardening
The Miller: General BLF communication
pepinfaxera: Interest list management
MRsDNF: Early prototyping
Neal: Facilitating tasks in China
Lumintop: Manufacturing

Who will be seller ? I am asking because i have payment issues with GB.

Updated list : ā€¦ . . . . C L O S E D
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Primary Interest List, (main): See Post # 4, Page 1 .
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pepinfaxera: Interest List: See #Post , Page 111

pepinfaxera: Interest List, duplicate: See # Post , Page 71 ,
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1233 - # Post . bansuri
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New requests:
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Correcting: ā€¦
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1125 - # Post . Bob_McBob

Apologies, Iā€™m sorry.
I need to edit list.
Greetings.

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ā€“18 Off : # Post . DB Custom , See # Post . ā€¦ ā€œDelete, Removeā€
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ā€“1174 Off : # Post . CM2010 , See #Post . ā€¦ ā€œDelete, Removeā€
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ā€“931 Off : # Post . darrylo 3nd ā€¦ ā€œDelete, Removeā€
ā€“932 Off: # Post . darrylo 4nd ā€¦ ā€œDelete, Removeā€
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ā€“1344 Off : See # Post Coscar, delete , ā€œRemoveā€

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Totally agree. This summer, I replaced my BLF A6 cycling light with a Zebralight SC600w MkIV Plus. The BLF A6 uses a FET+1 driver with a XP-L, and the Zebralight a boost driver with an XHP50.2. I like to use about 700 lumens when cycling, and the BLF A6 would give me about 1 hour of output before it dims too much to be useful to me. The Zebralight gives me a constant 700 lumens for almost 3 hours, until the battery is drained to 2.8v. (Both using a Sanyo GA cell.)

While I like the BLF A6 as a casual light, there are some circumstances where FET will not do, and even a 8x7135 like a Convoy wonā€™t do either. When run-time and constant output is required, you gotta go boost or buck/boost.

I wonder if thereā€™s a way in firmware to increase the PWM duty cycle of a FET driver as the battery voltage drops? It wouldnā€™t help with efficiency, but it would help to regulate output much better (on levels below max).

This is one of the differences between a $20 light and a $100 light. Some folks might prefer the A6 along with extra batteries for well less than half the cost. Good arguments can be made for both lights.

Luckily things get better as time goes on. We are close to getting high powered (40+ watt) aftermarket boost drivers with sweet UIā€™s like NarsilM and Anduril. Maybe in a few more months?

At the present time we only have medium powered drivers (20W) with a set - low, med, high, turbo and dbl clk for strobe - user interface. :confounded:

Maybe the next BLF light can use a boost driver. :+1:

That would probably be costly for BLF standardsā€¦but Iā€™d like to see that happen.

How much more is a boost driver, compared to the usual FET+1 drivers that budget lights use?

I could be wrong, but Iā€™ve got a feeling it could be a significant price difference for a good boost driver compared to a FET +1 driver, in terms of Chinese production cost.

Lexel said it would cost over $20 for him to make a high powered 17 mm boost driver.
In a BLF project it could be cheaper:

  • increasing driver size would enable use of cheaper components
  • labour in China is cheaper
  • larger scale saves a lot

Soā€¦I donā€™t know, but maybe up to $10 premium?
Then thereā€™s a question of what LED would be involved.

  • XHP35 is quite expensive considering its output. The work-in-progress drivers can drive it to the full potential
  • XHP50.2 is a bit more expensive per unit, but cheaper per-lumen. The work-in-progress drivers can drive it reasonably hard, but not to the limit
  • XHP70.2 is actually quite cheap per-lumen, but the work-in-progress drivers wouldnā€™t be able to drive it hard
  • Some Nichia? Luxeon?
  • Multiple 3V LEDs?