Ultrafire WF-501 with MC-E drop-in

HansV

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Mar 9, 2010
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I have a Ultrafire WF-501 that is getting a MC-E drop-in from DX(SKU 21037).
There are two big limitations on this setup that I hope to fix. The drop-in module is not a close fit in the flashlight head, and will have poor thermal conduction. There is a 0.5mm gap between the modul and the inside of the head, and this will cause the module to heat up fast. I have solved this by cutting a sheet of 0.5mm aluminium and wrapped it around the module. Not it is a nice press-fit in the head, and will give good cooling of the module.
The next problem is the driver. It doesn't give more that about 2A. I would like to have a current closer to 3A. For this, I will dry to skip the driver and run it directly on a protectec 18650 cell. But before I do this, I will set up the light in my testjig connected to a lab supply and a solar panel in front to measure the light output. Then I will measure what current that gives maximum output when the flashlight warms up. I might have to use a small resistor(0.1ohm?) to limit the current.
I have done a similar test with a Trustfire TR-801 using a XP-G R5. The sweet spot for that was about 1.5A before the output startet to drop when increasing the current. But the MC-E has better thermal management(3deg/watt), so it should go a lot higher. And this is a bigger light too and should provide better cooling.
Another modification I will do is to fill up part of the room for the driver circuit with solder to increase the thermal transfer from the LED to the flashlight. The brass under the LED is quite thin, and increasing the thickness of the metal here should drop the LED temperature.
With this setup it should be possible to pass 500 lumen output. The MC-E can make 700lumen with 10W drive and with loss in the reflector and beacuse of the temperatur, 500 lumen actual output should be realistic in a setup providing good cooling.

I will try to post some pictures later.

Does anyone have other ideas on how to get the most out of this light with the MC-E? I have been thinking of making my own driver board to limit the output current, and will possibly to this if I have to. It can be done easy making a regulator with a MOSFET transistor and a tiny OPAMP. Can fit fine on a 16mm board and regulate 2-3A with less that 50mv drop.
 
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Fichtenelch

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May 23, 2009
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435
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Germany
you could just swap a shiningbeam 8x7135 driver in it and it wil deliver 2.8A (if you swap the wires the driver comes with to bigger ones)
 

HansV

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Joined
Mar 9, 2010
Messages
70
Location
Norway
I am using one Ultrafire XSL18650 2600mAh protected cell.
Currently I am running it direcly without a driver, and that seems to work fine. It's pulling about 3.7A from a fresh battery and drops slowly when the battery discharges.
I testet this setup in my solar panel output test jig, and the output was still inceasing well beyond 3A drive current. I think the thermal connection between the emitter and flashlight head is has gotten very good. I used 0.5mm aluminium around the modul to fill the gap, filled half the room for the driver with solder and packed everything well with thermal grease when mounting it. I also lapped the back side of the emitter board to make it flat for better heat transfer. Good cooling makes all the difference:)
It has a fast drop in the output the first secounds when the LED die heats up. After dropping about 10% it stops and only fall off slowly when the whole flashlight heats up. The head reaches about 60 degrees C after a few minutes. This should give a die temperature a bit above 100 degrees. Then the output should drop less that 20%, with is specified in the datasheet at 125 degrees die temperature. Peak output should be about 800 lumen minus loss in the optics, dropping to 600 when it heats up. But I have no means to verify this.
This is build as a small "killer" light to impress friends and not a everyday light. I wanted to se how much I easily could get out of a small and cheep 18650 flashlight with easy modifications. But it seems to work fine and don' get too hot. I will only run it on protected batteries for safety reasons, just in case. It should be able to run about 30 minutes before the battery runs low.
 
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