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Fraz Labs Mechanical Flashlights (formerly QTC Non-Battery Crush)

kerneldrop

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Apr 24, 2021
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Would anyone have more specifics on built in resistances and runaways? Recalling reading somewhere about a 4A value for this, what does it mean? Does this value change across models? Is there a way to measure the built in resistance on a given light?

The short answer for us commoners is no.

Stick to a Keeppower 18650 protected battery and you'll be good to go forever.
Order it from Malkoff or Illumn.com

Avoid high-drain batteries. High drain meaning 30-50amps.

Everything affects resistance....age, temperature, conditions, battery, literally every thing, QTC, distance from the battery to the LED, what all is between the battery and the LED, etc and it constantly changes....

As volts decrease the amps increase.
As heat increases so does amps.
The more amps you have the shorter the life of the LED.
Heat kills LEDs.
Heat = unused energy that is not converted into light
 

ecmp

Newly Enlightened
Joined
Aug 15, 2016
Messages
88
I'm looking into the new E21A LEDs. I haven't tested them yet, but they should work just fine within a reasonable Vf

What is a reasonable Vf range to consider?

We've used mainly unprotected cells because they are shorter and the batteries typically perform better in this design (especially with the safer chemistries we have available now). I'll post a pic of the batteries we use shortly.

As for the batteries, there are resistances built into the design that keeps the amperage well below nuclear levels on high discharge batteries. I like them because of the shorter stature, good bang they provide, and safe-at-low-discharge chemistry available in some of the newer cells. Also the electronics in protected cells I'm afraid would become the fail-point in some of the high-impact tests we do (although I definitely need to try that out). That being said, I will start buying some protected cells and see how well I can overlap the battery tube offerings. Or possibly make them adjustable. I'm working to acquire a bulk load of QTC now so hopefully I will be able to start selling those pills as well.

Yes, any of the batteries in the 3.7 (4.2) volt range will run the light. And a primary 3v cr123 will run it as well but a bit dimmer. A single 1.5v cell doesn't have the umph, but 2 or (max) 3 1.5v primaries will run it. I hope to have more battery tube/spacer options as we scale our manufacturing better.

I'm tinkering with some designs that have an adjustment mechanism for the longer batteries but they are still being prototyped. For now generally the unprotected, safe-chemistry, high-discharge battery varieties are what I use.

What would be the safest chemistries listed in order of safest to least safe?

What specifications do we look for?

Batteries with higher discharge generally have lower capacities. Looking to be able to determine the lowest discharge battery for a given emitter at direct drive. What emitter specification do we look for here? If a battery has a lower discharge rate than the emitter, would it equate to having a less bright output at direct drive or will it mean a runaway?

Have found 16650 batteries with same rated discharge rate and capacity to 21700 batteries. Why are 16650 batteries preferred in some cases? What are the advantages?

In the case of fully degraded QTC (which my current EDC is fully degraded QTC that has turned to powder basically), the light will continue to function by simply having to tinker to get levels or a full twist for direct-drive.

If you ever want to test the full capability of whichever battery you are using, you can take the QTC out of the piston and then turn the light on with no QTC in the system. That will make the light go into full direct-drive.

Even at .06A the QTC still puts through the full voltage of the cells. QTC is strange stuff. At max brightness or at the lowest moonlight levels, the voltage going through the system is the same (only the amperage changes).

Correct, it is regulated by the QTC until full-compression where it goes into direct drive. There, it can pull anywhere between 2-4A depending on the emitter and battery (mostly the battery), but intentionally stops at around 4A to avoid a runaway. We're tinkering now with some hotter models that can really let some stuff like the SST40 eat.
EDC is correct, mechanical resistance is built into the system to avoid overrunning. With the extra emphasis on heatsinking and the resistance springs, we haven't had one overrun yet.

What are the specifications on both the emitter and battery that one needs to ensure to avoid runaways?

Does the newer model flashlights all intentionally stop at 4A to prevent runaways? Can the 4A value be measured by ie., a DMM? How?

With different LED and Battery specifications, what values to we need to know and how do we determine the maximum pull?

With 4A max pull of the emitter / battery combination at direct drive, would a 4A rated continuous discharge battery be optimal? What advantages would a 15A rated continuous discharge battery have?

Any of the modern LEDs will work with the forward voltage and built-in resistance of the system. I try to get as low forward voltage as possible generally.

How can we determine the range of the forward voltage and resistance of the system? What are the specifications for these in the latest QT-SS drop?

Currently the Tiny Nugget runs 18350, 18500, 18650, and soon 21700....all different battery tube options that interchange with the engine.

The Tiny Nugget 18650, 18350, 18500, and now 21700 all are interchangeable with the Tiny Nugget Engine now.

Would the latest QT-SS have a battery tube option for 21700?

In my opinion it also looks cool - and now only has 2 possible points of water incursion....at the optic, and at the battery tube. Which are both water-sealed tight. Getting rid of the battery tube tail cap and bezel on the front feels real good. Machining them however was a nightmare at first.

Is getting rid of the battery tube tail cap a feature for the smaller 18350 cells only or also feasible for the 18650 while still accommodating both protected and unprotected cells?

Yep, Geisto is correct - just need an LED on a 16mm MCPCB!

The best thing about our flashlights is that any emitter will work in the thing, as long as it's on a 16mm MCPCB.

Do we assume MCPCB thickness are equal or is there a range for that?

Going through the threads and trying to compile specifications and information for a rough guide on how to best enjoy the full range of options for a Fraz - for the layman.
 

ecmp

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Joined
Aug 15, 2016
Messages
88
Here's a photo of the newest version of the QT series, the QT-SS!!
@speckacuda
What would be the range of 18650 battery sizes that can fit in the new QT-SS drop? Will the longer protected cells ie., Nitecore NL1835 18650 2.73" x 0.74" (69.3mm x 18.7mm) fit?
 

TheFraz

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Joined
Aug 22, 2007
Messages
492
Location
Little Rock, AR
@speckacuda
What would be the range of 18650 battery sizes that can fit in the new QT-SS drop? Will the longer protected cells ie., Nitecore NL1835 18650 2.73" x 0.74" (69.3mm x 18.7mm) fit?
Hey guys! Long time no see. I'm gonna start trying to get on here and answer questions more often (as I've told myself before....but this time I'm really gonna do it...).

The batteries we've used range from 2.56" to 2.65" in length with no problem. I've EDC'd both of those lengths for extended periods. The newer battery tubes, including the QT-SS, have an adjustable plug on the end that lets you tinker with battery lengths a bit. I've never tried the Nitecore NL 1835, but I believe it should work with the plug extended. I'll order one and find out. Width shouldn't be a problem with any of them.

-Fraz
 

TheFraz

Enlightened
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Aug 22, 2007
Messages
492
Location
Little Rock, AR
@ecmp questions from above:

Vf ranges, we've used all of the modern Vfs of high 2s to low 3s and up for single-cell applications (the usual 3.7v nominal li-ion battery types). I haven't specifically tested any of them, we're just going off the manufacturer specs. Mainly the SST20s and Samsung 351D varieties, but we've also used CREE XP-L, XM-L, XP-G and Nichia series as well as SST40. All of them work well as the light has very good heat sinking (as you can tell when the light is on direct drive it gets warm quickly).

As for battery chemistry, we used to use the 26650 unprotected ICRs with our first lights, but now use a bit of everything (protected and unprotected). The LED stops working before the battery fully discharges in the cases we've tested (usually in the low 2v range). I would still very much recommend getting the battery with the lowest safe discharge capacity that you can find.

There is enough resistance built into the system to avoid a runaway. You can measure the current through the system with a meter in series. I usually do it at the tailcap. The current will vary between LED and battery types (as well as how far 'on' you have it dialed) but the resistance in the system will limit it well short of the battery max discharge potential.

We're looking into 21700 battery tube options. It's going to require a bit of additional R&D to get it as smooth as the 18650, but it's coming. We're also looking into 18350 battery tube options both with and without tailcap (boring those tubes without tailcap can be a bit tricky).

All the MCPCBs we've used are approximately the same thickness.
 

TheFraz

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Joined
Aug 22, 2007
Messages
492
Location
Little Rock, AR
The short answer for us commoners is no.

Stick to a Keeppower 18650 protected battery and you'll be good to go forever.
Order it from Malkoff or Illumn.com

Avoid high-drain batteries. High drain meaning 30-50amps.

Everything affects resistance....age, temperature, conditions, battery, literally every thing, QTC, distance from the battery to the LED, what all is between the battery and the LED, etc and it constantly changes....

As volts decrease the amps increase.
As heat increases so does amps.
The more amps you have the shorter the life of the LED.
Heat kills LEDs.
Heat = unused energy that is not converted into light
What kernel said (looked for a pointing 'up' emoji, but couldn't find one....). I've measured all this stuff before, but it can be a real pain and nearly requires some custom parts. Also, the numbers vary as kernel said.
 

TheFraz

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Aug 22, 2007
Messages
492
Location
Little Rock, AR
Will be back on in a bit to work further up the list. I think yall are gonna like the SS lights. I've been EDCing one for a couple weeks exclusively in my pocket with my keys and knife....not a scratch! Never had a stainless light before, but I can definitely see the advantages.
 

ecmp

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Joined
Aug 15, 2016
Messages
88
Thank you for the clarifications @TheFraz!

For the emitter

Forward current is from 0.2A to 3A
Forward voltage is from 2.7V to 3.3V

For the LG 18650 unprotected battery
https://www.nkon.nl/sk/k/Specification INR18650MJ1 22.08.2014.pdf

Maximum voltage is 4.2V
End voltage is 2.5V
Max discharge current is 10A
Maximum height is 65.2mm or 2.57 inches

For the Nitecore 18650 protected battery

Maximum voltage is 4.25V
End voltage is 2.5V
Max discharge current is 4A
Height is 69.3mm or 2.73 inches 🤔

Both batteries have a capacity of 3500mAh which seems to be the highest available in the market.

Concern would be the overlap of amperage and voltage ranges between a given emitter and battery. Assuming a worst case scenario of having to go direct drive, how can one choose an emitter and battery combination that would not fry the emitter?

Maybe a possible method is to plug in the resistance value of the flashlight into a formula? Since the flashlight design varies across drops, it might be helpful to have data on this.

Would understand the emitter forward voltage range of 2.7V to 3.3V to mean that there would already be no light output at 2.7V. With battery cut off at 2.5V, would understand it to mean that the danger of draining the battery beyond the cut off is not possible with the above emitter / battery mix. However, as the maximum battery voltage is around 4.2V while the emitter's is only 3.3V concern would be:

1.) the flashlight resistance value that made it safe (at direct drive)

2.) how this resistance would affect the minimum voltage before there would be no light output (can consider emitters with lower minimum voltage then?)
 

ecmp

Newly Enlightened
Joined
Aug 15, 2016
Messages
88
What kernel said (looked for a pointing 'up' emoji, but couldn't find one....). I've measured all this stuff before, but it can be a real pain and nearly requires some custom parts. Also, the numbers vary as kernel said.

It is the varying numbers that make things interesting! Looking to have a better grasp of these to be able to maximize emitter options and battery capacity.

Will be back on in a bit to work further up the list. I think yall are gonna like the SS lights. I've been EDCing one for a couple weeks exclusively in my pocket with my keys and knife....not a scratch! Never had a stainless light before, but I can definitely see the advantages.

Can't wait for the SS order to arrive!

Would be interesting to know by how much a stainless version transfers heat out of the light and durability when compared to aluminum, brass, and … hardened BeCu.
 
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