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EverLED Diamond
Luxeon LED Retrofit Upgrade
To Fit PF Oldham Caplamps etc
EverLEDtm Diamond from www.coldspark.co.uk - Price £23.95
The Oldham Caplamp has been around more than a few years. The Manchester based company has been producing underground lighting systems for about a century, and their legendry caplamps have been (and still are) used in mines all over the world. It's not that they are particularly bright or technically sophisticated, it's simply that they are absolutely bomb proof in construction and ready to take on the harshest underground environments. For instance mine was made in 1963, spending about 40 years of its life in a gruelling coal mine before I was given it as a present. They are very popular with Cavers and Mine-Explorers as well as for professional use. But this isn't a review of the Oldham Caplamp, it's a review of a neat LED upgrade available for it.
Important Note: Some Oldham Caplamps use the screw-thread MES fitting bulbs for the main light. If your main bulb is the MES type (not the pilot bulb, these are always MES), this upgrade won't fit! You'll need an adapter first for your Oldham so it can take PF fitting bulbs. Also, Speleotechnics do a range of popular caplamps (FX2, FX3, FX5 etc) though these all seem to fitted with MES-type bulbs, so this Luxeon upgrade unfortunately won't fit in these lamps. I don't know if an adaptor is available.
The standard Oldham Caplamp comes with a waist-mounted, 4 volt battery. This is connected by a strong cable to the actual lamp, which usually has two bulbs in (there is a switch so you can select which one you want to use) The factory-standard main bulb is a 4 watt halogen, with the pilot bulb about 1 watt. You can buy other bulbs to fit in there, either brighter ones that eat the battery quicker or weaker ones that give a longer duration. I upgraded my main bulb from a 4 watt to a 6 watt about a year ago, as I like the extra light I get although it's a pain lugging huge batteries around if I'm having a long day underground.
I won't go into a huge narrative all about LEDs. What I will say, if you haven't come across them, is that they are generally more power efficient than traditional bulbs (well, make better use of similar light output), and give off a lovely, smooth white light rather than the familiar blotchy yellow light. They also don't blow if you whack them, as any explorer who's clomped their head on a rock only to be thrown into pitch black will testify as being a good thing. Although LEDs have been around for many, many years, it's only in recent times that technology companies have started to find ways to make them bright enough for serious lighting applications.
One such company is Lumileds (now owned by Philips) and they produce a popular range of LEDs called the Luxeons. These LEDs are then bought by other manufacturers for inclusion into their own lighting products. At time of writing, Lumileds produce high-output LEDs in 1watt, 3watt and 5watt versions. Caplamps and torches are available based on all three of these LED sizes (for instance, Speleotechnics produce a Caplamp range based on the 3watt and 5watt Luxeons).
A number of manufacturers buy in Luxeons and use them to produce retrofit upgrades so that they can be placed in existing torches, caplamps etc. For instance, there is a 3watt version that is designed to fit into Maglite Torches.
Unfortunately for us Oldham owners however, it's not quite as simple as just going out and buying any old PF fitting Luxeon upgrade. The problem is that the vast majority of torches and lamps that use the PF fitting use the tip of the bulb for the positive current (+) and the case for the negative (-). Sadly our Oldhams are one of the very few lamps for which this is reversed (I.E., the bulb case is positive). It doesn't matter for normal filament based bulbs as it will light the same no matter which way the current flows, but for LEDs, it won't work if it's not right. Practically every LED PF bulb upgrade I've seen is understandably produced for the more common, case-negative type of light.
Ever-LED is (to date) one of the few manufacturers I know of that offer a Luxeon-based PF upgrade in a special reversed-polarity version. They call it the EverLEDtm Diamond, and because it's designed for the case to take the positive current, it'll work in an Oldham. So I ordered one.
What it is
The EverLED is based on a single, 1 watt Luxeon LED. It's a shame they don't do versions based on the bigger LEDs that Lumileds produce but there would be a complication in doing so - the 3w and 5w Luxeons produce masses of heat and need specialised heat-sinks so they don't melt into oblivion. This practicality would make it very difficult to manufacture a reliable PF bulb upgrade as the package is just too small to fit in a big enough heat-sink. The 1 watt Luxeons produce far less heat and so the thick brass case of the PF fitting is enough of a heat-sink on its own. Feat not though, for the 1 watt Luxeon is still no pansy, and will throw out as much light as a traditional filament bulb of a much higher wattage rating.
The other big advantage of this product over many of the other LED upgrade kits is that the bulb very cleverly has an electronic regulator circuit built into the brass case. This regulator is designed to provide the exact voltage the LED needs regardless of the incoming voltage, so the bulb will work just great on anything from 1.5 volts to 9 volts, and that's impressive. It also means that as the battery slowly wears down, the light remains bright and punchy, then dims quickly as the battery reaches the end of it's charge. A regulated light over a non-regulated type is a real advantage.
The Package
The EverLED arrived in a neat little cardboard box, inside of which
was a great plastic display case (a bit like a box that a
ring might come in). This gives a handy place to keep your old bulb!
 The box it arrived in |
 That's a nice case! |
The Bulb
Opening the case, I used a bit of tissue to extract the actual bulb (you really shouldn't touch it!). The case was made of chunky brass, obviously to aid cooling. Etched into the side was "EVER LED" and a diamond symbol, to indicate that this was the reverse-polarity version. On the end was the side-emitting 1 watt Luxeon element, which was surprisingly small compared to a normal bulb.
The EverLED itself
The supplied instructions were for the regular, case-negative type. I couldn't see any polarity markings on the bulb itself so if you didn't know exactly what you ordered you'd be forgiven for thinking the polarity was case-negative. But no, this is indeed the case-positive version so it will work with my Oldham.
Fitting
This couldn't have been easier really, I just opened the Oldham,
removed the old Halogen bulb and slotted the EverLED into the
socket.
 My 6 watt halogen next to the new EverLED |
 The Oldham Caplamp with the EverLED fitted |
The new bulb fitted perfectly as expected, and I screwed the bezel back onto the Oldham. No problems at all.
Switching On
I turned the switch of my Oldham and was suddenly blinded by a heavenly white burst of light, very different to the yellow light that I was used to coming off the reflector. I was impressed, and shone the beam around the room (which was clearly visible on the walls despite it being a bright sunny day outside).
 The centre spot from the EverLED |
 The centre spot from the Halogen |
The beam was narrowly focused, and threw a long way. It was also even and round, and rather easy on the eye. It wasn't really as bright as my 6 watt halogen bulb, but there didn't seem to be much in it, and bear in mind the EverLED uses a fraction of the power (1/6!) which means I can stay in mines for six times longer on the same battery. Wandering around the house at night suggested to me that it will do its job in a mine just fine, especially for smaller mine tunnels (or caves) where a really powerful light output isn't required.
Testing Down a Mine
To give the EverLED a proper test, I gathered up some friends and off we went to the biggest slate mine in the area for an 8/9 hour trip through a variety of terrain including narrow passages, wide passages, 240ft high chambers, abseils, rock-climbs, crawls and scrambles.
Cavers / Explorers tend to prefer lights that fall into one of two groups: Some favour lights that give a wide, even glow which give great local visibility and clarity, but lack in range. The other type prefer light with a narrow beam but great travel. The EverLED (when mounted in an Oldham Caplamp) gives very much the latter case, which is not what I was used to (my old 6w halogen bulb had been sand-blasted so that it provided a very diffused, unfocused output). Hence, from when I first entered the mine and for the first hour or so, I was a bit nervous and wondering if I'd made a mistake.
After that time I started getting used to it, and came to realise that in actual fact this was a pretty nice light to see by. Although I could only illuminate a small circle at a time, I was impressed to discover that I could clearly see chamber walls nearly 200 feet away. My old 6w bulb, despite consuming six times the power, could barely manage 50 feet.
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Petzl Zoom Zoom's are a popular but cheap 2.5w halogen headlamp often underground. |
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Oldham with an EverLED The spill is not very bright but still sufficient. The centre spot throws a long way to pick out distant detail. |
My friends (being of the flashy sort) had strong 3w Luxeon based lamps. Each of them were also carrying absurdly powerful (but really very nice) gas-discharge diving lamps which acted like 40w LEDs might. My little light felt pretty weak in comparison, and my eyes were adjusting to their lights so that if I turned a corner first without them, I found myself struggling to see where I was going.
On one occasion in particular I managed to shake them off (they were busy fighting an enormous coil of super-static in a manway) and I stood alone in a large chamber to let my eyes adjust to my EverLED. I was very impressed that I could suddenly see the whole chamber, even the far side of it a good 200 foot in distance. Apart from the main 'spot', there was an even and wide throw of a weaker light which lit up the wall/floor close to me. The safety-standard logo on the front glass of the Oldham was clearly projected onto the floor and I could read it.
I decided there in that chamber that actually this light was very nice indeed and although weak compared to bigger lamps, it was certainly bright enough, even in this huge dark slate mine. I proceeded to get on fine with it for the whole trip, and never felt the urge to take one of my big torches from the bag.
Conclusion
I'd say the amount of light it threw out was probably similar to what a standard 4w (non-diffused) Oldham bulb does. This upgrade means you'll enjoy four times the burn-time, a clearer whiter light, and (virtually) no risk of the bulb blowing. Unlike a Halogen bulb that will get gradually dimmer throughout your trip, the EverLED will maintain almost full brightness right until the end of the batteries.
The EverLED cost about 24 pounds and for that money I reckon it's a pretty good deal. If you like an Oldham on your head, this is a nice upgrade that you'll be pleased with. There are (decent) headlamps available based on the 1 watt Luxeon for about 50 pounds, but if you've already got an Oldham this is an excellent way to upgrade your solid and proven lamp to modern LED technology. You can kit yourself out with a Luxeon-based headlamp with greater light output than this will do, but it'll likely cost you more than 24 pounds!
It's not the brightest beast on the market, but then Oldhams never were. This bulb won't really make your Oldham any brighter for you than it is with the factory standard 4w bulb, but it's the other advantages you'll gain by sticking one of these in. Couple it with a fresh 24ah Oldham T6 battery, and you should get the best part of 100 hours between recharges (that's about two weeks exploring at 7 hours per day).
All in all, I'm impressed with it and can say it certainly lives up to expectations. I don't regret the purchase at all and would recommend this product to any Oldham owner looking to upgrade to a Luxeon LED without having to buy a whole new lamp.
Many thanks to www.coldspark.co.uk for supplying me with a review unit!