Modding 'The Oval'

Fletch

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Sep 2, 2005
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Long time lurker. :wave: First time I have something worth posting…

The Oval flashlight seems like a neat light for walking and running, and it is. But being a flashaholic, I wanted to see if I could crank up the power a little bit. So I opened it up.

oval_mod1.jpg


There's quite a bit of room in there – looks like enough for a Luxeon, heatsink, and reflector.

oval_mod2.jpg


I decided to remove the stock cluster of 4 leds and replace it with a 1W luxeon and IMS reflector. The compromise? No more regulation (check out the runtime graph at flashlightreviews.com!) and reduced runtime. Possibly some issues with heat. I decided to direct-drive the luxeon at about 200mA, underdriven to maintain decent battery life and reduce heat.

The install is simple. Desolder the power and ground wires going to the stock circuit board. Solder the resistor(s) (I used two 2.2Ohm resistors) into place, and solder the power and ground to the luxeon. You don't need to touch the switch or downward-facing led cluster. I found a little cpu heatsink that fit perfectly and stuck it to the back of the luxeon. It's dimensions are .825" x .825" x .25".

oval_mod3.jpg


Next came a 17mm IMS reflector (great beam!) and .75" mineral glass lens (from ofrei.com) which slides right into the existing slot. It all fits really well.

oval_mod4.jpg


Screw the body back together and that's it! It works great. Puts out more light and I love the beam quality that the IMS reflector gives.

oval_mod5.jpg


oval_mod6.jpg


I would like to install a regulator of some kind - like a micropuck, except I think the micropuck goes direct-drive when over 3V, so it would overdrive the Lux1 and create a lot of heat. Any ideas on a different driver? There's plenty of space in there to put it. :help:

It also might be fun to throw a 3 watter in there, but I'd probably drill out the body to try to get some ventilation… I think the 3 watter would also completely overpower the 'downward' leds and make the light less functional, but it might be fun anyways.

Enjoy!
 

HarryN

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That is a nice mod - well thought out.

At 200 - 300ma, you can pretty much ignore having a great thermal path to the outside world, and the output from a Lux III vs I will be different, but unlikely double, so you are in a pretty good operating condition there.

There is relatively little excess voltage available from 3 x AAA, so a driver board will not provide substantially more efficiency or run time, if any. Perhaps the best upgrade will be high quality cells, such as Li primary or NiMH if you use it a lot.

That is the first time I have seen that flashlight - had to look it up. It certainly is large for holding only a couple of 5mm leds as the stock configuration.

I wonder how much more battery power could be stuffed in there ?
 

Fletch

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Sep 2, 2005
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Just a quick clarification for Harry... The flashlight uses 3 AA batteries, not AAA. Should give pretty good runtime, even with regular alkalines?
 

HarryN

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You can get a good estimate of your runtime by looking in the battery / electronics section - silverfox - notes on AA cells. He has examined a variety of cells. Li will always out run the Alk.
 

Lunal_Tic

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Jul 29, 2004
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The Wilds of Tokyo
That's a slick job. I've got one of these coming just to see what it's about. I thought it came with the new Nichia CS LEDs was it not very bright with those?

Does the Lux overpower the remaining 5mm LEDs?

-LT
 

Fletch

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Sep 2, 2005
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Just got back from a nighttime dog-walk. The Oval luxeon worked great...

LT - I would say the 'stock' Nichia's are plenty bright for what it is intended to do. It's really bright for a 4 LED unit. But I don't like to leave well enough alone sometimes :naughty:. Plus I just love the beam quality, shape, and spill of the IMS reflector.

At the output level I chose (200mA), the remaining LEDs are not overpowered at all - the light works wonderfully. I would imagine that if you ran it at full power it might not 'feel right'.

That brings me to another project... To install a luxeon for the lower led as well. I checked it out and it looks do-able, but will require an emitter (which I don't have at the moment) or some major surgery to the 'star' pcb. Maybe later I'll look into it more.
 
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