Searching for a 3 or 5 watt Luxeon Led for FX5

[potholer]

U = luminous flux = 87 - 113 lumens (in the minimum-to-average range, but still very bright)
XI = Colour temperature ~6300 kelvin (fairly mainstream, but possibly slightly blueish)
T = Forward voltage 6.39-6.87V (slightly more sensitive than the typical LED)
W = White LED (rather than red, amber, etc)

The forward voltage is the most important bit. I'm not sure what an FX5 battery voltage is under load, but it looks like you'd get *pretty much* full power without needing a fancy circuit.
It's possible that if the LED is at the low end of that voltage range (~6.4V), maybe the voltage of a freshly charged battery could even be slightly high, and some small resistance might be useful.

It does seem that the 5W luxeons have a much more limited life expectancy than the 1W and 3W pieces, and particularly depends on good heatsinking (500 hours with a heatsink temperature of 35 Celsius leaves the 5W at 90% of original brightness, 500 hours with a heatsink at 85 Celsius leaves it at ~65% of original brightness).
The figures may well be a bit pessimistic, but it certainly seems worth doing whatever you can practically do to keep it cool.

 

[Stu]

potholer

Is there a handy reference type guide this information can be gotten?

 

[potholer]

For the product binning codes:
http://www.lumileds.com/pdfs/AB21.PDF

I'm not sure 'handy' is the word - first time around, it takes a little reading to work out which letters are the relevant codes.

For the general Luxeon V data sheet:
http://www.lumileds.com/pdfs/protected/DS40.PDF

 

[Stu]

Cheers matey.

 

[darkplaces]

Ok, installed Luxeon into a spair head lamp. Had to sand down the reflector to fit. I used it down in box today, it was ok, plenty of wide angle nice light BUT no beam and it had a big dark shadow in the middle. I'm going to have to figure out how to focus this thing or add another reflector. It didnt burn up and worked on the FX5. So really just the focus is the problem to solve now.

Picture here;

Any ideas anyone?

 

[Fred]

A commercially available (apologies) solution to the current supply might be a "Buck Puck".

LEd Supply

These units can supply enough for a 5w Luxeon and the packages are pretty small (implies PIC solution?) but I guess would still have to go outside your haed set. However international shipping is more than the cost of a single unit!

For a true homemade solution maybe Speleogroup might a a start - they've got both an analogue and a single chip design (but no code) for a 1w Luxeon driver which might be modified. Alternatively try googling on buck boost or similar.

Also you'd still have to deal with the heat generated by the Luxeon itself.

 

[ijg0]

Not sure how much space you have left in the headset but one of the following may be suitable:

Luxeonstar Lenses

 

[potholer]

I'm surprised about having a dark shadow in the middle - the 1W and 3W Emitters are brightest head-on, with intensity falling off gradually as you get further off-axis, so I'd expect the 5W to have a similar beam pattern. The datasheets seem to suggest the same, so I guess what might be happening is the light being emitted onto the reflector is making a badly focussed beam-of-sorts that is projecting light in a ring, giving the impression of a dark centre.
Do you still get the dark centre even with the reflector missing?

For focussing a Luxeon emitter, you'd need either
a) a lens arrangement, (which you may not have room for if you are mounting your Luxeon on the bulb-holder bar, since the lenses seem to be about 20-25mm deep).
or
b) something like I use - firing downwards into half a reflector, which gives something over half the light going into the beam, and the rest fired down to the floor in front of the caver.
If you look at http://www.bisun.co.uk/images/resources/sidegraph_spotlight.gif
you'll get the general idea (ignore the top half of the graphic)

Oddly enough, I got an unexpected enquiry at the weekend about the possibilities of building a simple LED-based setup running straight off an FX5, without the twin beams or power-control of the units I normally build, so I may end up doing something along those lines myself.

 

[darkplaces]

I solved the darkhole issue. It was focusing. Running out of room in the headlamp and wanting to keep it as simple as pos. to limit breakdowns I thought of how to resolve without extra reflectors etc.

In the end I ignored the heat issue and mounted the star luxeon inside the reflector, drilled a couple of holes in it and secured the thing with tiewraps (FANGtastic things) and it works! I took it for a test drive for 3 hours and it didnt melt. and I had a small but nice bright beam with the much wanted smooth light all around for good side vision.

Improvments and modifications I am thinking about mounting the LED in a side position but I think I need to do more testing.

Since this picture I have removed the tiewraps and used superglue.

 

[potholer]

Excellent.

The two possibly undesirable features of the way I mount the spot-beam LED in my lights are:
1) There isn't really any light 'above' the spot beam. While this does have advantages - you don't blind other cavers with light as long as your spot beam points below their face - it does mean that spot-beam-only isn't ideal for climbs and other situations where you want to look up above the level of the spot beam.

2) The maximum light (outside the beam) is straight down (or put another way, the minimum light (outside the beam) is in a horizontal band, level with the beam, where the LED is essentially being looked at edge-on. Whether this is good or bad depends on the situation (on climbs, often good lighting at foot-level without having to tilt the light down can be useful, but in other situations it may be less desired.

In my lights, I can run both LEDs at once if desired, so that solves whatever problems may arise in various situations. In crawls, etc, I tend to just use my (unfocussed) wide beam, and leave the spot off.
Lighting's so much a matter of personal taste anyway that what one person sees as a possible problem can be just the way someone else likes things.

If heat isn't a problem, your current way does give a possibly better combination of beam and wide light from a single LED than my arrangement. I think my setup would pack more light into the beam, though with a 5W LED, maybe that isn't so important.

PS -Thanks to your mentioning where you got your 5W LED from, I now have a new and rather cheaper source of 3W parts for my lights. Cheers.

 

[darkplaces]

Well glad I could help in some way. I just hope when the lamp has its second test tonight the superglue doesnt melt. I just wonder how many hours I am going to get with a 5 watt led out of an FX5.

 

[potholer]

>>"I just wonder how many hours I am going to get with a 5 watt led out of an FX5."

It's a complex thing - with a load like a bulb, the battery voltage will decline very slowly for most of the battery life, and then drop quickly towards the end - by the time you notice a yellowing of light, you may only have a short time before the bulb is giving a useless glow.

However, the voltage/current characteristics of the LED are different to a bulb. As the battery voltage drops, the current the LED pulls drops more quickly, which means that the LED will quickly dim, but will draw proportionally less current, and it will be quite a long time between the brightness starting to decline and the light becoming useless.

The initial time at relatively full brightness (on the flat part of the battery discharge curve) will depend how much current your particular diode is taking off a relatively fresh battery.

If your FX5 is in good condition (and assuming I'm right in thinking they use ~7Ah cells), I'd guess maybe 7-12 hours at fairly full brightness (depending on the LED), and then quite a few more hours of declining light.
Though it's always tricky estimating how much light a lamp puts out, even with another lamp to compare with, to get some idea of your lamp's end-of-battery-life performance, I suppose you could run it flat, give it a ~10% charge, and then see how long it takes to run down from there to being actually unusable.

If you're getting some sort of beam out of it, you could still have a usable lamp even when pulling very low currents - on my lights, the wide beam is OK for close-up lighting and moving in known cave at ~30mA (~1/12W), but the spot beam at the same power level gives a surprisingly good throw of light, though the light outside the beam is pretty dim.

<off-topic>
For general construction (apart from gluing LEDs to heatsinks, where I prefer JB Weld, mentioned earlier), I've found Wilkinson's own-brand rapid epoxy to be pretty good. Seems as effective as Araldite, and is only £1-89 for 2x15ml tubes, so less than half the standard Araldite price. Apart from the first pack I bought, none of the packs I've used have been clear, - despite what the pacakging says, it actually sets white. Still, pointing that out to them got me a £5 voucher, which was another 2.5 packs for free...
</off-topic>

 

[darkplaces]

Cheers pot.. 7-13 hrs, at just an estimated guess sounds just the ticket to me. Longest I'v been underground is about 9 hrs.

I tested the unit out tonight, it didnt melt, the superglue held and didnt melt and I got a wide throw of light with a fuzzy clump of white beam in the middle, I jolly well think this is it! At only 5 watts its not as bright as my 6 or 10 watt haligens which are brill for large quarrys but the 5 watt luxeon does the business on longer harder working trips. So I am rather pleased. Its a 'cheap' nova without the inverter electronics. I'll keep test driving this thing. Luckly the superglue I just picked off the shelf in maplins set transparent. I used 'KwickFix SuperGlue'.

Personally I think they made the nova over complex & costly. Initally its 5 level of brightness was simply not needed, all you want is on, off, side, otherwise you end up cycling though the combinations all the time. I prefer a pilot builb pointing down, means you dont blind people when huddled in a group showing people were they are on the map.

They say the luxeon will almost never break, yeah right, gimme two builbs atleast when I'm underground.

 

[potholer]

I do find a twin-beam light rather more reassuring myself.

I've met a handful of people using Novas, most of whom seem (unfortunately for me) reasonably happy with them.
I was caving with someone a few months ago who was using a borrowed Nova that started flashing (presumably due to low battery), and carried on strobing away happily (and pretty uselessly) thereafter, whatever power level it was set to, which seemed odd, and possibly isn't the way they are meant to behave.
I sold him one of my units for an expedition he was going on, and I haven't heard from him since. I'm working on the theory that that's good news...

I think the new Novas only have 3 power levels, which is probably enough. I decided to only have (up to) 3 power levels in my lights, changing power by a factor of 3 or more between levels, since more closely-spaced power levels are very hard to distinguish in actual use, and, being skewed to expedition use, I wanted a very miserly low power setting for general sitting around or caving in relatively easy passage. Getting up to a week of continuous burn off a 4.5V Duracell does give a nice feeling of security with a spare battery in your pocket, especially when caving with someone on carbide, using a temperamental Ariane.