www.littlemonkeycaving.co.uk

The Monkey House 

How far things have moved on since we started manufacturing lights for cavers in the mid 90s. They said that our helmet mounted nimh rechargeable battery packs wouldn't catch on! But now it is the normal, albeit with more powerful li-ion cells.

7/5AF cells (similar size to modern 18650 li-ion cells). 3 cells were essential, because they were wired in series (1.2v each).

And we are of course still here, doing our thing, driving the tech forward.

In 1997 we manufactured quite probably the first commercial white LED caving light solution for cavers. We were very fortunate to get a head start with the technology. We had industrial connections with Nichia in UK, and got hold of these amazing (at the time) white LEDs, before they were commercially released. At this time there was very limited information on the internet about this sort of thing, so very few people were aware what technology was coming.

Our first white LED products were 1, 3 and 7 LED conversions for Oldham and CEAG mining lamps. These were very quick to market, and sold widely via the caving shops (remember those ?) in the UK and beyond. Three of these LEDs ran from less than 0.1A, and this certainly helped helmet mounted batteries to gain in popularity. Many said that you needed 30 to 50 of these LEDs for a viable caving light, but one Nichia is just plenty if you are sitting out a little bit of flooding in a certain French gouffre, above Little Monkey and Puits de l'Ouragan, for those that know the place.  

Of course all caving light manufacturers now use white LEDs. Every innovation is replicated sooner or later. No complaints, you just have to plug away and keep ahead of the pack. 

A couple of our prototype Nichia LED lamps from 1998. But we were busy working in automotive research at this time (plus the Nichia LEDs were really rather expensive, and 20 in a lamp was cost prohibitive), so these designs were never commercially developed.

And then, within a fairly short space of time, Luxeon launched a new generation of high power LEDs, and the move towards modern LED caving lamps as we now know them was set.  

Our original machined aluminium Little Monkey lamps from 2008. 7.4v li-ion powered lights with Seoul P4 LED (producing around 230 lumen at 1A). Crumbs! We have certainly learned a lot since we manufactured these, and of course taken on board much input from fellow cavers.

At this time LED caving lights typically required 7.4v li-ion packs (or in some cases 11.1v), as LEDs had higher forward voltage and required higher voltage battery packs to operate effectively.

Around this time we also introduced the Customduo LED conversion modules, for the popular Petzl Duo. Our range of modules has evolved significanlty, and the original Petzl Duo remains as popular as ever with cavers.

Photos left show some of our earliest (relatively crude) Customduo conversions. To see our most recent designs, visit www.customduo.co.uk   

In 2010 we introduced the Rude Nora. The Nora1 was far from the finished article that is now the Nora4. However, it did mark a significant, though largely un-noticed, leap forward in caving light tech !!

Improvements in LEDs now made them ideally suited to operation from more versatile, lower voltage battery arrangements, and a new generation of high power LED caving lights became possible, running at 3.7v. 

As LEDs became more efficient, providing more light and producing less heat (along with increased battery capacities), much smaller lamps could be designed, with similarly effective heat sinking capability.  And this evolution continues. While the Nora 1 was relatively compact for the time (AA battery for scale), it now seems rather bulky when compared our current the Nora4 and Edna2 lamps.

Not forgetting the Nora 1 battery box, the first dive cable box of its type, tested to -100m. 

The Nora 1 box used a 3x18650 arrangement providing capacity similar to what can now be acieved with 2x18650 batteries, an instant 50% reduction in battery weight on helmet and battery cost.    

In 2013 we introduced the first two cell 18650 caving battery box allowing used cells to be easily exchanged. This now widely replicated arrangement provides optimal helmet balance, with batteries on the back and lamp on the front.  

With advances in LED and battery technology, a 24 hour trip using 2x18650 cells is a breeze for the well skilled caver. Far more light output and longer runtimes are achievable than was possible just a few years ago from a bulky 4 cell box. If and when doing longer 24+ hours trips, then it makes obvious sense to pack spare battery capacity with other kit required for such a trip, rather than lugging this around on your head, wrecking your neck. 

It would, as the technology currently sits, now be difficult to justify designing a heavy weight battery box solution with more cells, especially as lamps can be designed that are much smaller and lighter, as LEDs waste less energy as heat and consequently cooling requirement is reduced.