As most underground explorers will be aware, there is something of a revolution going on with cap lamps. The traditional bulb headsets are gradually been superseded by lights systems based on Light Emitting Diodes (LED's). There are a range of products on the market, and there seems to be a lot of discussion as to what is the  best, the Stenlight and Speloetechnics Nova 3 running favourites. There are however, other contenders, and the most useful amongst these must be the Retro 2 manufactured by Technical Concepts Ltd. You can read all about it here: http://www.mineexplorer.org.uk/ledlighting.htm

I recently spent a very full day underground in the Caplecleugh mine at Nenthead with its designer Mike Hrybyk. The trip was rather like an underground version of SAS selection with wet rises, chin deep water, muck crawls the full works. Coming out, my lamp went dim as I was underground longer than expected, however with Mike right behind me with his Retro on full blast it was no sweat finding my way. I left with a very favourable impression of this unit as seeing it in action for a full day under the most arduous conditions is worth a lot more than seeing something being demonstrated in a shop. I have to mention in passing that the unit has recently been up rated with more powerful Seoul P4 LED units which means there is now a total light output of 200 lumens making it probably the most powerful on the market.

The beauty of this unit is that it is intended as an upgrade for the standard Oldham GT caplamp 4 volt lead/acid or the Speleotechnics batteries, but can be connected to virtually any battery with output between 1.3 and 6 volts. You can run one on 3 or 4 AA rechargeable's if you want in a home made holder or the one that is sold for the Nova. This gives an incredible durability compared with the others intended to run on lithium ion batteries.

Now I have not had the opportunity to test the Stenlight or the Nova, but I am uncomfortable with their unsuitability for use with an Oldham or Raylight lead acid battery. Both are severely limited by their batteries if used continually on full power, you get about 4 hours, (Nova on FX3 battery). You can of course purchase spare batteries and carry them with you underground changing batteries as required. Unfortunately, there's the cost. Stenlight itself weighs in at £195 complete with battery and charger. Your extra batteries will set you back £35 each, so you are talking £265 with 2 spare batteries. You cannot connect this to any other battery so you are stuck with the manufacturers lithium ion. The quoted light output is 160 lumens. The Nova 3 connected to the FX3 belt worn battery still would not have sufficient durability. An extra FX3 battery would cost you £74 so your in the same price bracket as the Stenlight. Serious mine explorers can spend a full day underground in spacious surroundings where they will just want to leave their lamp on max power.

I purchased a Retro 2 and did some tests in Wilkinsons Level, a fairly dry walk in level at Talybont, where I seem to spend most of time these days. A friend from Welsh Mines Society had a standard Oldham T6 caplamp, I had the retro 2 and an Oldham T6 with a 1.5 amp (6 watt) halogen bulb conversion.

So what about the Retro 2. Well for a start the price is right at £75. Fitting is usually easy, full instructions supplied, and if you run it continuously on full power you will still get 23 hours out of an as new Oldham 16 amp hour battery. This is enough for a weekend with 2 full days and no recharge facility. To the best of my knowledge if you want to run really bright LED lighting on an Oldham or Raylight lead acid battery its the only ball park in town anyway.

I set my digital camera on a tripod and did a few preliminary tests to get the best picture using the Retro 2, and then using the same settings took some pictures using the other light sources. My camera is another really good piece of kit, its the Fujifilm S9500 which has a fixed 28mm to 300 mm telephoto zoom lens, as well as an external flash socket, essential for underground use. Its made of high impact plastic same as the Styr AUG Assault Rifle, and high impact means what it says. In Brownley Hill mine I knocked the tripod over and the camera crashed onto some rocks but was completely undamaged. My setting was ASA 400, 2 seconds exposure at F4. The pictures cannot really tell the full story, as there is no lens made that can duplicate the human eye. My friends standard Oldham was basically as dim as proverbial TOC H lamp, I don't think he had even fitted a halogen bulb. I would not go underground with it. My up rated Oldham was a real searchlight, I always refer to them as a "Caving Supplies Flamethrower" as these are the people  where I get the up rated bulbs. The range was especially good, mainly because it was focused to a narrow beam. By the way, if you don't know this, a prefocus bulb can be focused by rotating it in the housing until the desired beam pattern is achieved. It marginally beat the Retro 2 on this, but at the price of peripheral illumination. I have to say that the outright winner was the Retro, the quality of light is such that you can see all the natural colours underground as you would in daylight.

The real tie breaker is the power consumption. Oldham lead acid batteries at the moment seem to start life giving almost 20 hours on the standard bulb, but within 12 months fall back dramatically. I am hearing this all round. I would expect a 16 ampere hour battery that does what it says on the tin to give 16 hours on a 1 amp bulb, about 10 or 11 on the up rated 1.5 amp bulb, and 21 hours on the Retro 2 on full power. So its really no contest.

This is the Oldham standard 1 amp caplamp. One could try eating carrots.

This is the Oldham modified with a 1.5 amp halogen bulb.

This is the Retro 2 on full power

This is the Retro 2 on medium power

This is the Retro 2 on low power

This is a painted in photo of Paul Smyth using the the Retro 2 on full power

This is a painted in photo of Paul Smyth using the 1.5 amp halogen. Note the yellow appearance and streaky effect

There are finally two points that I have to strongly emphasise, these relate to 2 reviews that I have read on the Retro2.

#1 Price Comparisons

I have seen price comparisons with the Nova where this is done without taking into account the cost of the Nova battery. As they come with 1 battery, both the Nova and the Stenlight are useless for full day trips. Only fair price comparison is Nova with FX3 and spare battery, and Stenlight with 2 spare batteries, each compared against Retro2 with new Oldham MF and headset assembly. A new MF off Caving Supplies is £76.35 which amounts to £151.35 with Retro2 conversion against about £260 for Nova or Stenlight. Of course, who really wants to mess about underground changing batteries anyway?

Purchasing new headset, lid, and cable is unnecessary in most cases anyway, so new MF battery only is £30.25, or £48.60 for a T6.

# 2 Light Comparisons

Light comparisons in the reviews I have seen are unfair as the new version Retro2 has double the power of the old, due to the use of Seoul P4s instead of Luxeons.  

OCTOBER 2007

I have had a very enjoyable weekend at Nenthead and now have had opportunity to witness the alternatives underground.

Nova 3: Sorry to say that I am very unimpressed with this, the light output appeared very poor compared with the Retro and the Stenlight.

Stenlight: My good friend Ian Hebson uses these and I met him on the car park, he just come out of Caplecleugh, me out of Rampgill. As I was cold and just got changed we compared lighting by shining into the mouth of Rampgill, it being quite dusk outside. He agreed that the Retro was probably putting out more light, however the Stenlight was more focused. It was also a very impressive piece of kit, the headset being extremely small. The whole thing was surprisingly tiny, they aught to pack them in jewel cases! I was very impressed, but no so with the battery lead. Also I re-iterate what I say above about battery life. Ian uses it continuously on the mid setting so basically gets his day out of it. Its a personal thing but I like maximum amount of light, probably because I go underground on my own a lot.

The "Chinese" model: This is a another contender and I haven't seen one of these before and don't know who is selling them. Although the light output from a single small LED is not great, the beam is a perfect circular unbroken focus, therefore puts out a greater percentage of what one would call "useful" light. I understand its selling for about £140 and the I was assured that it will give 15 hours on main beam. Its certainly a serious contender.

UPDATE: Its http://www.ledcavinglamp.co.uk/ and they are £130 plus £10 postage. Simply described as "LED lighting system" its the lamp with no name.

I also enjoyed the company of Steve Holding who was using the Retro connected to a SpeleoTechnics AA battery pack, Caving Supplies sell these for about £8. Its a very cheap lightweight powerful lamp.

NOVEMBER 2007

I have finally got to see the famous Scurion in action. The power of it was very impressive, possibly the best of the lot. The cost of it wasn't at £275, and I also have some reservations about its robustness as the lens is the full diameter of the headset and I wonder what would happen if it suffered a blow. The competition is very fierce and I expect that more new developments are in the pipeline. I would counsel very strongly against spending a lot of money at this point in time, hence my support for the Retro. If you already have a good Oldham lamp and simply want more powerful lighting the Retro is the only way to go.