greenforce diamond mod?

Hi,

I have a greenforce diamond (a bit similar to an ultrafire W200). it uses 2 CR123A batteries to drive a 700mA driver. This driver powers a luxeon lumiled LED.
The optic is a tir optic, but when I got the light (2nd hand), it was loose in the housing so the beam wasn't very impressive.
After putting the optic back in the holder, the beam was more or less acceptable.

I'm wondering if it could be modded. It is said that the burn time at 100% is about 2h, which would indicate that the batteries are about 750mAh when the led has a Vf of abuot 3.15V.
I think the minimum burntime should be at least 1h. Any suggestions?

The space for the optic is about 28mm (diameter) so it should be fairly easy to replace.
Would it make sense to replace it by a cree XPG?

johan

I've not seen an LED with Vf of 3.15V. Newer Crees are around 3.35, older and other makers are 3.7+ at full power. Good CR123s are 1400mA-H, so a 2 hour burn at 700 mA sounds like a linear driver. You could probably increase the burn time substantially (30--50%) by switching to a switching regulator.

28mm diameter is just right for an Ahorton aspheric, which will give you great beam if you want tight focus. For medium focus use a deep reflector. For wide or flood use shallow or no reflector.

D

28mm you say?

Try an ahorton aspheric and a XR-E.

+1 on the Ahorton aspheric - a great pieve of kit. MUCH better then the 28mm aspheric from DX. I cant advise on the LED though.

I haven't found the datasheet yet of the LED, but found descriptions on DX etc like this:
Luxeon Lumiled 3W 700mA LED Emitter (LXHL-PW09)
- BIN # LXHL-PW09 TX0HW
- Luxeon 1W Lumiled LED emitter
- Typical driving current: 700mA
- Driving voltage: 3.0~3.27V
- Color temperature: 6700K White
- Manufacturer's rated lumens: 80 lm

that's where I took the 3.15V from.
80lm is pretty disapointing. by just replacing the led by a cree xre, I can already double the output. using an XPG probably would increase it a little more but probably not too much.

I don't have ahorton aspherics at the moment because I didn't have a good use for them until now and they aren't cheap enough to just buy them. But I hear the quality is good.
I found the height of the lens to be 14mm, how much space do I need behind the lens?
I'm afraid it won't fit. 1 important difference between the W200 and the GF Diamond is that you cannot push something entirely through the head if you understand what I mean. There is a base where the led is mounted on which is part of the light head. I could drill a hole, but it would be difficult to do that nicely aligned with the rest of the head I think.

I do have the DX 21mm aspherics, perhaps I'll test with this first to see how much space is available.




DIWdiver, I'm not sure if it is a linear regulator. It has a fairly large encased inductor and quite some caps, resistors and other components. I haven't disassembled that yet, so couldn't read the text on the chips yet. I know there's a microntroller in it as it blinks once when you switch it on.

I'll see if I can take pictures of it, but unfortunately I'll have little time the coming 2 weeks to the traveling to different parts of the world.

Johan

Those specs are a bit confusing. Draining two CR123s in two hours would take about a 4 watt load. They claim a 1W LED (which would be driven at 350 mA), then say the typical drive is 700 mA, which would give you around 2W in the LED. Philips does claim the Rebel has a forward voltage of 3.2V typical at 700 mA, so at least that is consistent. From your description it does appear to have a switchmode regulator, but they seem to have managed only around 60% efficiency. That's not very good even for the low-end market.

The lowest bin of Rebel produces 80 lm minimum at 350 mA, maybe that's where the number comes from, but it produces typically 145 lm at 700 mA, where the highest bin is 220. By contrast the best XP-G is 260 at that current, or with a better regulator you could push it to an amp and get 350 without sacrificing burn time or increasing the heat load in the light.

I doubt the dx info is entirely correct. I'm guessing it's a luxeon III led (based on how it looks like) which would mean a higher Vf. It is certainly not a rebel, since that led looks totally different
this datasheet:
http://www.sparkfun.com/datasheets/Components/Luxeon-III.pdf
seems to confirm the 80lm, although at 1A and only 60-65 at 0.7A. the luxeon III has 3.7V Vf at 0.7A.

Regarding burntime, after some more searching, it is apparently burning 2h at 100% and will then gradually lower in intensity for another 4h (they say 4h at 50%). This way you probably don't take 4W from the batteries.

I measured the depth from the topside, and depending on how far the led is behind an ahorton lens, it may fit. anybody knows how much space you need behand the lens?

I measured the available height for led and optic if I don't modify the head itself. I've only 18mm available, so with the 14mm lens height, and about 15mm needed behind the ahorton, I'm afraid this won't be an option? I prefer to keep the head intact since it makes the heatsink a lot easier.

I did however find some interesting fresnel lenses with a similar diameter and focal length, which could fit in there. I'll post some pictures of the disassembled head later.

Hi guys,

just back from holiday and in the mean time, my lenses arrived so I'm putting together the mod.
first I made a POM/delrin holder for the lens. it fits nicely in the head and over the LED. There is a smal edge to support the lens. The lens is at the same height as the outside of the holder.


The original LED is replaced by an XML.

I could have used an XPG or XRE as well, but opted for the XML due to the bigger die. Otherwise I think the spot is just too small for it's purpose.

Here is the lens installed:


This is the original greenforce driver (700mA) that will go back in for now:


I'm currently waiting for the glue to dry so I can solder the LED to the driver and put everything together. I did a quick test with a different driver (3xAMC) to verify the focus of the lens and it seemed perfect. I'll post more pics when everything is put together. I'll also see if I can still make a shot of the original led and optic to compare to the mod.

Johan

Hi guys,

time for (above water) beamshots ;-)
First I made a picture with the original LED and original TIR optic. It's just placed on the table and pointing to the ceiling.


Then I connected the XML with the fresnel optic, put the head in the same place as the other setup:


I then made profiles of the intensity to compare the 2. The data is normalized to the maximum intensity:


You can see that the upgrade doubled the intensity while also making a more even beam. The FWHM is however slightly bigger, but still very good in my opinion. I didn't measure the FWHM yet, that will be something for the coming days.

So, without even changing the electronics, I more than doubled the usable output. I'm pretty happy with that

Johan

jspeybro said:

Click to expand...

that frensel is so close to MB SUB - X1 FF/VF ...... and the eay how lens is clamped ... (MB SUB have lens with 33mm diameter )

I was tought that GF have TIR optic ?

Otherwise ...nice work !

lucca brassi said:

I was tought that GF have TIR optic ?

Otherwise ...nice work !

Click to expand...

Yes, they do have a TIR by default. I replaced it with this fresnel lens and made the lens holder on my lathe because that TIR optic is terrible and the LED is from the stone ages ;-). The fresnel lens is just pushed in from the front and the friction keeps it in. There is a small edge just below the lens to keep you from pushing it in too far. The height is simply the available height in the head so this keeps it nicely in place.

It's a very nice lens. I think I'm going to use these in some other mods as well.

lucca brassi said:

that frensel is so close to MB SUB - X1 FF/VF ...... and the eay how lens is clamped ... (MB SUB have lens with 33mm diameter )

Click to expand...

I probably already asked, but do you know the focal length or distance between the led and the lens for that 33mm lens? I haven't found any lenses that come in a better focal length to diameter ratio than this one. I don't have a ahorton lens to compare it with, but I think it will be quite similar and with 1/7th of the height.

@33mm diameter used on CREE XR-E is

wide at 17,78mm ( measured on base of heatsink (so you have to add star PCB width ))

and spot on (17,78 +10,62 (curve between min. and max. )=28,4mm

----------------------------------------------------------
like frensell because are so light ; which one you have used (store ?)

Hi guys,

got my hands on another one of these GF diamonds. I'm going to do the same mod for the lens, but would also like to change the driver and LED this time to drive an XPG at about 1.5A or an XML up to 2A. By default it uses 2 CR123A primary batteries, but i'm thinking of using regargables so in that case, the voltage will be higher.
Any suggestions for a driver? max diameter is 20mm.

I was initially considering an AMC based driver, but I think the input voltage will be too high, certainly if I would use rechargables.

ok, after looking to all the stuff I had bought from DX over the last years, I found a good solution I think.
I found a sku 26110 from DX, which is at 1.25A. Adding a 1ohm resistor in parallel to the sense resistor, will give me 1.5A for an XPG, it's small enough and can cope with the voltage ranges I had in mind.
If I put 2x 1ohm in parallel, it would give me 1.75A so that would be nice with an XML and still give me a nice burn time of about an hour.
Still waiting on my thermal glue to finish the mod...

Johan

Finally managed to finish this mod.
Using the DX 26110 with an aditional 1Ohm resistor and these little fresnel lenses makes this a very nice mod. The new driver puts out the double of the original current and due to the smaller die, the spot is also smaller and intenser. I can't wait to try it out but it's too cold for me now.

If anyone is interested in these Fresnel lenses as well, PM me. I've got a few to spare and they are great for these lamps but also for the ultrafire W200, and I can imagine all P60 style lights.
Comparing these lenses to an ahorton lens, they are optically almost the same. The ahorton lens has a slightly shorter focal length making it capture slightly more light, but on the other hand, these fresnel lenses are only 2mm in heigth making them much easier to work with in dive lights.

Johan

I ordered a lens by Johan and updated my old Halcyon 10W lighthead with this optic. The main work was done some times ago, so I already had a XM-L with a driver from Taskled and a big copper heatsink. The reflector I used was a Fraen FRC reflector for an Ostar. Till I updated with the Fresnel lens this combination was the best the nicest Spot and I tried a lot.


LED with Heatsink


Lighthead with the old reflector


Machining the lensholder


The lensholder was made of POM


Adjusting the lensholder to the cables


Beamshot #1 Fresnel lens reversed about 2300 Lux @ 1 m


Beamshot #2 Fresnel Lens aright mounted about 12200 Lux @ 1 m


Beamshot #3 Fraen FRC reflector about 9700 Lux @1 m


Beamshot #4 Fresnel Lens aright mounted @about 2.5 m


Complete unit


Detailed front view

The Lux enhancement ist not very much, but all the light is in the square, against the reflector which is flooding some light out of the focus. I want to do some testdives to decide which setup is better.

For the beamshot the complete unit took about 0.91A at exactly 12V (~11W).

What is the distance from the back of the LED to the lens?
How wide is the beam at what distance?

The distance between the back of the LED and the lens is about 15.5mm, depending on how far away you focus it.
I'll try to do a measurement of the beam from my mod tonight, but I'm using an XPG, aixdiver uses an XML.