In recent years some serious LED lighting has evolved, Speleo Technics produced the Nova, and there are also the Stenlight and the Scurion, the later being what some consider to be outrageously expensive.

It is not surprising that some people would apply their intellect to devising means of converting existing Oldham headsets to high power LED lighting. Notably the BiSun and the Retro2. Of these the latter is in my opinion a superb piece of electronic engineering. Designed by Mike Hrybyk it is a beautiful piece of kit, one only has to look at it to appreciate the professionalism in its construction. I used one of these for at least 12 months with no problems whatsoever.

However, a new emitter appeared on the block, the Cree Q5 X-RE, and recently the Cree R5 X-PG. These are basically super emitters in that they have very high output of  light that is of a very high colour temperature, basically similar to daylight.

With this new boy on the block it is hardly surprising that people would start to look at the prospect of converting existing Oldhams using this new emitter. This is where I decided to try my hand at it, and I saw an interesting challenge in the idea of producing something really powerful as a conversion for exiting Oldham’s.

I eventually gave a lot a thought to the matter, and started a series of experiments that went on for about 2 months. There are 2 issues relevant to any attempt to put serious LED lighting into any caplamp, this apples to manufactured lamps such as the Stenlight and Scurion as much as to a converted Oldham.

#1 Getting rid of the heat generated by the LEDs

#2 Providing sufficient battery capacity for a reasonable burn time when the power consumption is high.

Of the 2, the first is the most problematic

I started this towards the end of 2008, and it has been an intensive learning curve, but a very interesting and absorbing time.

The main issue when I started with my lamp building was getting rid of the heat generated by the LEDs.
Initial thoughts were of getting aluminium extensions manufactured that would replace the Oldham bezel assembly, but with a forward thread to take this, in event a sort of aluminium extension. This would hopefully provide adequate external heatsinking as well as more interior room. The blow was the cost of having these made, this caused me to look in other directions.

Aluminium as we all know has excellent heat conducting (thermal conductivity) properties, and is also a very light metal. However, it is far from being the best heat conductor. Its rating is 200k compared with 390k of copper, nearly double; this soon caused me to think about the possibility of making a copper thermal conductor that was part of the plastic caplamp. At the same time I was able to source some high pressure PVC pipework components which included a nut of the same size as the Oldham headset outer rim. An advantage of PVC is that it can be solvent welded. This is not ‘gluing’ in the normal sense, but means what it says on the tin.
I soon realised that with a bit of thinking I might be actually able to improve on an all aluminium design. First one has to get the heat out of the lamp body; next one has to dissipate it into the air, basically, 2 separate issues.

After a lot of experimentation I developed a thermodynamic solution that produced a reasonably well designed practical lamp. I fitted this with a cast aluminium reflector that had 3 borings for the LEDs. 3 Cree Q5 XR-E emitters were fitted, 1 working of the first switch position, the other 2 of the other, so it was either 1 or 2.

Testing indoors over about half and hour indicated a maximum internal temperature of 32 degrees centigrade, underground it barely got warm, a sure indication the system was capable of supporting a lot more. It was a good lamp, underground I met a chap with a standard Scurion who readily admitted my lamp was brighter.

My next experiment was to produce a similar lamp that had a 5 bore cast reflector and would power either the one, or 4 Crees at full power. This must have been producing between 900 and 1000 lumens yet running it indoors it never went above 72 degrees centigrade!

I also began to appreciate that testing indoors for temperature is no indication of the heat retained in the lamp underground. From the start I underestimated the effectiveness of the system, it is now my contention that this system will give up heat better than a lamp made entirely of aluminium.

Next I devised electronics that would bring the 5^th Q5 on line, the result was the first of the MagnumStars.

At that point in time, I concentrated on producing a reduced size model of my 480 lumen lamp. As the temperature remains low due to the incredible efficiency of my heatsinking system, there was obviously scope to reduce the size of this, and also, on that model, dump the front extension.

The result was my "UniStar" or universal lamp.

This describes my first experiments. Since then many lessons were leaned and techniques perfected that would form the basis of later more advanced creations.

Technology moves on, and at this time (Dec 2010) the UniStar has been discontinued.

The Trigon is now by far my most popular lamp, originally producing at full power almost 1200 lumens, now with Cree XM-L emitters producing 1600 lumens, yet it only has a small external heat sink area.

Cree Inc introduce a new generation of high efficiency LED emitters:

"CREE Breaks 200 Lumen per Watt Barrier

Cree have announced a reported laboratory efficacy record of 208 lumens per Watt; surpassing a significant milestone in the solid state lighting industry and demonstrating Cree’s relentless drive to improve the performance of its LEDs.

The results were measured under standard LED test conditions at a drive current of 350mA at room temperature. "

These new R5 XP-G and T6 XM-L emitters are now fitted to the EcoStar and Trigon.
 

XLampXP-G.pdf

XLampXM-L.pdf