Mod battery carriers to 8P1S (or 4P1S if there is the small tube) , and replace led it with dedomed sst-40 and a fet driver (still running Narsil) .

I will probably test it on a friend’s GT

giorgoskok wrote:

I will probably test it on a friend’s GT

U evil

He asked for it !

Made a C8 with dd sst40 and he loved it …

Don’t have a real use for the GT, so I will go for a old style xp-g2 for máximun throw ( maybe an oslon black flat later).
Now there are two ways for the driver depending on voltage.
4s: LD-3 driver. If I remember correctly it can drive a 3v led with four cells in series.
1s4p: using just one cell holder and a DD driver. This means making some new boards for the holder.

Any other options for a 3v led?

A380 wrote:

4s: LD-3 driver. If I remember correctly it can drive a 3v led with four cells in series.

This isn’t correct , led4power’s Ld-3 driver is direct drive style driver .

Other solution is buck driver from Richard (mountain electronics).

Nope, the LD-3 is a linear driver. It keeps the current constant as long as the batterys voltage is above the Vf of the LED. Excess voltage is burned off as heat in the driver.
It’s more efficient at some points compared to normal FET drivers and can keep your LED from dieing from too high currents.
It does have a DD option though if one really wants that.
An XP-G2 would require a 1S setup.

So the LD-3 can put down the votage from 4s to 1s led or not?

For a 1s set up cell holder I would need the help from someone to desing te board for oshpark.

No it can’t. It would burn up.

I want to see a XHP-70.2 on it! It should still throw like crazy at least farther than my eyes can see anyway with lots of lumens to spare

As Giorgoskok pointed out, a MTN buck driver is a good solution for a 3v led and no need to modify the cell holders. This one: http://www.mtnelectronics.com/index.php?route=product/product&path=67_11...
But remember that this driver must have a thermal path to the flashlight body.

With an xp-g* why not just use one cell per holder and use a bit of wire as a jumper, that way you can easily revert back to standard, same with two cells for 6v leds, and use three cells for those hard driven 6v leds

Cheers David

Nice idea David. That would be more on the budget side.

For an XP-G2 it would be highly preferable to use 2S battery set up with a buck driver, because the Vf of an XP-G2 is around 4 Volts or more when you drive it hard.

^^^ What he said

Cheers David

Does anybody knows what kind of max amps we can expect from the original driver (modded or not) on a xhp70(.2) ?

I’m pretty sure the xhp35 on mine wont stay long, i’ll transform the GT into my dream K60 on steroids.

Standard the driver puts out 2A on high and 2.5 on turbo, that should stay the same for all 12v leds.

I did read somewhere in the group-buy thread that it can be modded to 5A with cooling.

If I am wrong will someone please correct me

Cheers David

IIRC, 5A is indeed its limit. It definitely needs a good thermal connection to the flashlight body. Might even need more heat sinking at that power level.

What about a hardcore mod? (spacer needed).
- seven reflectors: http://kaidomain.com/p/S026180.42mm-x-57mm-SMO-Aluminum-Reflector
- 3P xhp-70.2 (12v configuration each) wired in paralel with 4s dedomed xp-g2.
- FET driver.

Only question, is there a 4s battery capable FET driver with electronic swhitch configuration for this mod?

A dded XHP35 is a must have for a modded GT, if XHP35 based ofc:at least 15, ( even 20% possible) bump in candelas

The Miller : shall we have a spare drivers for that light? Or at least an Oshpark PCB option

A380 wrote:

What about a hardcore mod? (apacer needed).
- seven reflectors: http://kaidomain.com/p/S026180.42mm-x-57mm-SMO-Aluminum-Reflector
- 3P xhp-70.2 (12v configuration each) wired in paralel with 4s dedomed xp-g2.
- FET driver.

Only question, is there a 4s battery capable FET driver with electronic swhitch configuration for this mod?

Like that idea,Or how about 7 XHP-35? 14,000 to 17,500+ throwy lumens?

Mitko wrote:

A dded XHP35 is a must have for a modded GT, if XHP35 based ofc:at least 15, ( even 20% possible) bump in candelas

The Miller : shall we have a spare drivers for that light? Or at least an Oshpark PCB option

Ready and waiting…..

De-Domed XHP35’s E2’s E4’s, XPL W2’s, Old School 6.3amp XP-G2 and even a DD 70.2 just for kicks!

3amp 4S Linear Drivers are ready too, so contact boards will be needed or just wipe the stock one clean!

How about spare reflectors for purchase also!

A380 wrote:

What about a hardcore mod? (apacer needed).
- seven reflectors: http://kaidomain.com/p/S026180.42mm-x-57mm-SMO-Aluminum-Reflector
- 3P xhp-70.2 (12v configuration each) wired in paralel with 4s dedomed xp-g2.
- FET driver.

Only question, is there a 4s battery capable FET driver with electronic swhitch configuration for this mod?

You probably don’t want that deep reflector.
Deep reflectors are not what you hope for.
You get a very wide and bright corona and not much throw.

A380 wrote:

What about a hardcore mod? (apacer needed).
- seven reflectors: http://kaidomain.com/p/S026180.42mm-x-57mm-SMO-Aluminum-Reflector
- 3P xhp-70.2 (12v configuration each) wired in paralel with 4s dedomed xp-g2.
- FET driver.

Only question, is there a 4s battery capable FET driver with electronic swhitch configuration for this mod?

NarsilM with TA LDO drivers just running the FET should work well
just need to figure out the resistor value for 4S to get proper LVP

Jerommel: correct me if I am wrong, but as far as I know throw depends on reflectors diameter. A taller reflector makes the hotspot to be smaller (this is the reason for choosing them).

Lexel: But this driver needs to be build and programed. Don’t have the skills for the firmware stuff.

A380 wrote:

Jerommel: correct me if I am wrong, but as far as I know throw depends on reflectors diameter. A taller reflector makes the hotspot to be smaller (this is the reason for choosing them).

It doesn’t.
It’s because the shorter reflector is a section of a larger parabola, so the focal distance is bigger with a shorter reflector, or in other words, the LED is relatively smaller in relation to the parabola with a shorter reflector, resulting in a tighter beam.
Also, the amount of extra light that is reflected with a tall reflector is not that significant.

You will see that the best throwers have a shorter reflector.
They are never taller than they are wide, usually they are a little shorter than the width.

The surface area of a reflector (as seen from the hotspot, so a 2D circle) determines the throw for a given lightsource. It doesn’t matter how big or small the hotspot actually is. Only the luminous intensity matters (measured in candela or “lux@1m”).

The area of a reflector is mainly influenced by the diameter of the large opening because area_of_circle = radius^2 x pi. For a given outer diameter changing the depth of a reflector does have a small effect because the smaller hole at the bottom must get smaller. Thus the area is a bit larger, but it’s a very small effect.

Deeper reflectors do change the shape of the beam. The hotspot becomes smaller, the corona bigger, and the spill angle smaller compared to shallower reflectors of the same diameter.

Thanks both for the explanation.

The_Driver wrote:

The surface area of a reflector (as seen from the hotspot, so a 2D circle) determines the throw for a given lightsource.

The throw is determined by both the frontal surface area and the focal distance (the distance between the LED and the reflector surface)
I would say it is determined by the size of the parabola actually, the bigger the parabola (in relation to the LED) the better.
Depth doesn’t make too much of a difference, that’s why we see reflectors are usually shorter than their width.

Quote:

It doesn’t matter how big or small the hotspot actually is. Only the luminous intensity matters (measured in candela or “lux@1m”).

Obviously the intensity will be higher with a tighter beam = smaller hotspot.

Have a look at how little more light is reflected when you make the reflector deeper:

(dark red is typical flashlight proportions)

You have to add a lot of depth to catch an additional 5° from the LED, it’s not worth it.
But, it wouldn’t add too much width in all, so you could go for square proportions (width = depth)
But let me say this:
I have a light with a very deep reflector, which i bought when i thought it would be good for throw.
Well, it isn’t good for throw.
The base of that reflector is considerably narrower than a short one of the same diameter, resulting in a weak beam with a corona as big as the spill.
I guess this could be useful in certain circumstances, but it mainly adds length to the head of the flashlight and not throw.