Esp. for PeLu: What is recommended for caving lights?

PeLu: You appear to be the most experienced caver amongst us so you're probably most qualified to answer this, but anyone can chime in.

What would you recommend as a good electric light setup? Number of LEDs, wattage of filament bulb or HID, type of power source (NiMH, alkaline, lithium, etc.), capacity of power source (mAH), should it be dimmable, should the setup be combined LED and filament (or HID) with switchable between either light source? Aluminium or polycarbonate body? Angle of view? Able to focus? Any other specification?

There are probably many ready made ones available. Can you recommend any electric based lights for caving purposes? (hopefully dive capable as well, so cords must be sealed.)

Thanks very much.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Steelwolf:
PeLu: You appear to be the most experienced caver amongst us
<HR></BLOCKQUOTE>

As caves tend to hide themselfes this is not for shure...

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>What would you recommend as a good electric light setup? Number of LEDs, wattage of filament bulb or HID, type of power source (NiMH, alkaline, lithium, etc.), capacity of power source (mAH), should it be dimmable, should the setup be combined LED and filament (or HID) with switchable between either light source? Aluminium or polycarbonate body? Angle of view? Able to focus? Any other specification?<HR></BLOCKQUOTE>

[edit] I just lost much text due to paying not enough attention, therefore I will do it in more parts.

part1:

Actually I've written several articles about that in caving magazines.

1. People are different, cavers are even more. We still have a lot of debates about carbide versus electric lights. As you only ask for electric ones, we skip this question .-)

2. assuming cost is no real argument (actually it is much less of an argument as many cavers think).

3. For expedition use: Only completly helmet mounted lights are useable (cables from helemt down to a powerpack like to catch wall protrusions, thin cables break, thick ones hinder head movement).
Weight should be not more than 400g (~15ounzes) when you use a good helmet. It should be distributed in between front and rear almost equally.
You need about 15-50lm with 20-30° half width (this is about the light distribution you get with a couple of 20° Nichia LEDs), some people prefer a uniform light (like a ceiling burner carbide light or a fluorescent tube), there you need 50-120lm.
You will need also additional light levels. The spacing has to be around 1:4 (1:2 turned out to be too less, a variable setting is useless (but fun to play with)). A brighter setting will be needed for light eating passages, huge rooms and similar occcasions.
Less light will be needed in small passages and crawlways and for most ropework. Even less will be needed for a rest or when you have to wait. The brighter settings should be more focused.
For looking for leads or down pits, a strong spotlight is very useful. An equivalent to an SureFire P60 is the minimum.
For switching in between modes a turnkey is favorable. Just a single pushbutton is not than 'user friendly' (but may accepted).
The complete light has to be waterproof down to 100m (at least). Experience showed, that it is waterproof enough after a couple of years. It has to work also in temperature extremes.
Constant brightness on all settings (maybe except an emergency setting) is a very nice thing.
For the main light, LEDs are the best choice (for relyability and ruggedness). For the spotlight an incandescent may do the job, as it is not essential. For Nichia LEDs, 20-50 should be enough, when the Luxeons come to their claimed efficiency, 2-3 should do it.

Power source: The highest energy density comes in Li D cells, either LiSO2 or Li-Thionylcloride. If you use your light very much, you may think about rechargeables. Lates Li Ion cells are not that far behind the above mentioned D cells (look at at the FX Ion).
IMHO most people overemphasize rechargeables. You have several incertainities. You charger may not work well and even your cells may have a flaw. Actually I've seen many rechargeable lights failing or having a shorter runtime as expected. And it is just not possible everywhere to charge a light. Staying a week underground, several weeks on a mountain plateau or some time in a country with unrelyably mains supply causes some trouble for people with recharegable lights.

(now saving and continuing later)

part 2:

Actually I use about one D cell for 13-16 caving trips of 5-12 hours. But I'm low light person and I switch back or off at any occasion. I even like to climb ropes in complete darkness (you spend hours of climbing ropes here on some trips). At any rest, I switch off, as other people's carbide lights are still lighting everything around.

For the price of a high end rechargeable system you get a bunch of Li D cells. You will not get a battery and a charger for less than $200-$250, but you will get probably 20 Li D cells for this price.
But using a rechargeable battery will make you less greedy with your light and you will be more tempted to use higher brightness levels.
And on some expeditions, I like it very much when I don't have too much to work around with my gear. Not taking the muddy stuff out and connecting it to a charger and so on...(you may call it lazyness, I call it enhanced convenience).

Housing: I think a polycarbonate housing for the lighthead will be the best. Maybe the whole housing from one piece. Some people made pastic housings for an ActionLight module and they look nice. I should have pictures somewhere and could post it (As soon as I figured out how to do it).
For the battery a soft PU cover as used in FX lamps is the best.
For a charger you need one with a switching power supply. I has to work from 90-260V automatically. It is nice when you have a verbose charger, which tells you what happened.
For rechargeable and not rechargeable batteries, a fuel gauge will be nice (no idea now for primary cells).

And a perfect light for me will have one PeLu special: A single UV LED for checking minerals. So I just turn the knob for UV light.

Additional functions: SOS blinking function may be of some value and a timer function (light off after a couple of minutes). And a lock to prevent accidently activating the light.

You may add more functions......

Next part will be: Which lights are available and fulfill most of the needs..

forth part will be focused on non-expedition caving.

3rd part:

Some more remarks for the housing:

Aluminum housings have the advantage to make very good heatsinks, which is essential for high power LED lights when you care about efficiency.
The front part should not protrude too much, even when tilted down. Of course the up/down angle must be adjustable, but it may be a little bit automatic. Higher brightness levels could be aimed more up and vice versa.
When adjusting the light's tilt down, it should not protrude more. A good solution is a round light body which is easy to turn.

The light's switch should be as far away from the lighthead itself to avoid that you cover the lens with mud.

The connecting cable between the two parts should be easily replaceable by the user, as it is a potential point of failure.

front lens should be protected aginst scratching first by using the hardest possible material and/or by a sacrifying surface (replaceable plastic cover)

We were also talking about some kind of automatic brighness control. Experiments will show if it works in real life. Idea was, that when you looked at distant objects and therefore switched to a higher brightness and you afterwards look at your sketchbook close to your light, it will be too bright.

When using primary cells, some people think that'unusual cells' are a real drawback. It should be easy to make either a dummy D-cell which contains 4 AA cells or to use another battery pack. Actually for all users around here it has not been a problem up to now.

part 4

What is available?

For the lower end I prefer the LuxBrite. It is quite sturdy and inexpensive. It runs on 2 AA cells, if you prefer rechargeables, just take a pair NiMH cells and if it is not enbough use alkalines or LiFe cells as a backup. The light is waterproof, has a switch on the side (no need to twist the bezel). Using Petzl spare parts it is easy to convert it to a helmet mounted light (although easily detachable). We have some 30 of them around here and no malfunction until now. You can easily take two of them with you (and avoid to replace batteries in a cave). Unfortunately it has only one brightness setting. You can get the same housing with an incandescent bulb as an very inexpensive light to use it as a spare part kit. So scratching the front lens is no big deal.

If you can spend more, the ActionLight (as soon as it is available) is the top of the range. 'Current' model has the follwing drawback: It is heavier than necessesary, protrudes a little bit too much in front.
A model using AA cells should be available soon (on popular request), but I will stay with the Li D cells. A rechargeable model will be available as soon as I brought 3 manufacturers together. It is also lacking a spotlight currently, maybe one will come when demand is high enough. Until now an additional Surefire has to do the job. And it has no fuel gauge.

Both lights proofed their usefulness.

Untested, but good looking is the Lupine Stuby. Although it lacks lower light levels.
Ans has to proof caveworthyness.

I would be happy if anybody else tells us his/her available (electric) perfect caving light.

part 5 about non expedition caving and part 6 about emergency lights will follow (numbers may change). Maybe part 7 about carbide lights in 'General Light Discussions'.

So far lots of good info. I don't think I have yet seen any electric light with "remaining power" readout.

For responsive light level, I have an idea. Saw this arc welder's mask that uses a solar cell like you see on cheap solar powered calculators. The output of this solar cell acts as a control for an electronically controlled LCD screen/visor. It darkens instantly when the arc is struck. There is a control panel to select sensitivity.

The same concept can be applied to the head lamps, so that when plenty of light reflect back to the user, such as when writing on notepad, the circuit dims the light output. When looking far away, there is little reflected light, the circuit brightens the headlamp output. ie, the circuit attempts to maintain a constant level from the solar cells.

What do you think? Anyway, still eagerly waiting for parts 5 and 6. Not sure if part 7 about carbide lamps will be relevant to me since I can't get carbide easily.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Steelwolf:
I don't think I have yet seen any electric light with "remaining power" readout.
<HR></BLOCKQUOTE>

There are only rechargeable ones. I think the Lupine have it.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
For responsive light level,.... so that when plenty of light reflect back to the user, such as when writing on notepad, the circuit dims the light output. When looking far away, there is little reflected light, the circuit brightens the headlamp output. ie, the circuit attempts to maintain a constant level from the solar cells.<HR></BLOCKQUOTE>

This was the first attempt, it will be too 'nervous'.
First realisation will be that the bright part of the beam will be directed more horicontal and a lower sidebeam down.

Yesterday I met Daniel Chailloux in Munich, a well known french caver (showing his breath taking 3D slide show about Lechuguilla and other caves) who showed me some of his lights (the lowest has 19 LEDs and all have some step up or step down circuit), all of the very, very nicely made.

And another caver (a German) showed me his new white LED light with ~80 LEDs (he did not know the exact number, can you imageine that, and I did not take the time to count them). They are all in sockets, so they are easy to exchange and each LED has it's own resistor. They are connected to 3 or 4 D cells (using a converted MagLite as a battery holder).

Will hopefully have time next week to continue.

And I also learned that there is a french caver who already integrated an UV LED in his headlight.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Steelwolf:
So far lots of good info. I don't think I have yet seen any electric light with "remaining power" readout.
.<HR></BLOCKQUOTE>
I have a Tekna 4 D cell incandescent searchlight (w/ about a 6" reflector) on my desk here; little green,yellow, and red windows that light according to remaining battery life..Tekna had a 2aa cell model with this battery life indicator too, a few years ago (mine fell apart..) don't know if they're around anymore..?

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Ted the Led:

I have a Tekna 4 D cell incandescent searchlight (w/ about a 6" reflector) on my desk here; little green,yellow, and red windows that light according to remaining battery life..Tekna had a 2aa cell model with this battery life indicator too, a few years ago (mine fell apart..) don't know if they're around anymore..?<HR></BLOCKQUOTE>

Yes, I had one. A blue 2 AA light with a nice accesory kit (spare bulb was in the lanyard), but the light itself was not very sturdy (very un-Tekna like). Gas gauge was only for alkalines. How could I forget that..

When Molicell (a Canadian company) came to the market with the very first rechargeable Li cells they had a uncommon discharge curve:
The voltage was going down, starting at 4.0 V down to 2.5V (all from memory). This made some kind of volatge regulation necessarym, but on the other hand it made a simple gas gauge possible (accuracy better than 5% with no special means). Some people got a test kit which replaced a 2m radio's power pack (no, I did not get one, but it would have been possible .-)
The users reported about the specific advantages: higher capacity, lower weight, better low temp performance. But all agreed that the best part was the fuel gauge.
Have to look fo my Moli doku, now some 17 or so years old. Possibly it's collecting dust somewhere.

Y'all might not remember, but Luff rebuilt my Wheat Lamp using the original reflector but adding 20 LED's. It still has the incand. bulb and can be switched between the two.
I got well over 25 hrs of useful light on one 4volt 9AH battery.
It's plenty bright too! If I need more distance (which is rare) I can always switch to the incand. bulb via the rotary switch on the side.
My .02
Dude is right about the cord issue.Just tuck it into your mud suit if ya wear one.

part 5, lights for non expedition caving:

For just visiting caves (which is the most common kind of caving the vast majority of cavers in the US do) or for leading guided trips, a belt mounted powerpack is not so much of a problem.
But these trips lots of light is preferable. My perfect light with available technology will contain a 10W HID bulb and a power pack with 70-200 Wh (will give 6-18 hours of light). My own solution will contain several 12V 3.8Ah laptop computer power packs (for the simple reason I have 4 of these packs). Next version will use Li Ion cells. A LED light will be used as a backup.
I'm looking forward to get my hands on a Lupine Edison. Also weight is not such an issue for these light.
Because of it's high power consumption only a rechargeable powerpack will do the job. The light distribution will be a combined flood/spot (no problem as there is plenty of light). The light should have 500-1000 Lumen. Other cavers use incadescent lights for this job (for example one caver uses a SureFire M500 head bulb and 6 LiIon cells (and a LVR)) with the advantage that you may switch it on or off as much as you want.
Light level adjustment would be nice, but will probably not be offered by most lights (incandescent or HID) or in an only very reduced range.

Also non expedition caving is much less damaging the gear, so a HID may do the job.

Of course there are trip where you will prefer this setup even on an expedition trip and vice versa.

Is the typical HID only able to operate at single light level? ie can't be dimmed? It would also appear, from your description of use, that the HID is a little more susceptible to damage than even incandescents. But it is the most efficient bright power source, ie lumen/watt. Is that right?

As for Li-Ion batteries, where do you get them from and what sort of re-charger do you use?

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by vomit_stain:
Y'all might not remember, but Luff rebuilt my Wheat Lamp using the original reflector but adding 20 LED's.
<HR></BLOCKQUOTE>

Of course we remember it very well. But that's only a step in the right direction.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR> Dude is right about the cord issue.Just tuck it into your mud suit if ya wear one.<HR></BLOCKQUOTE>

It depends on your caving, but for alpine caving the cable is just annoying all the time. It still catches wall protrusions and hinders head movement. And you backpack is uncomfortable to wear above the cable (no expedition caving without ropes, drilling machine and lots of other stuff).

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Steelwolf:
Is the typical HID only able to operate at single light level? <HR></BLOCKQUOTE>

Yes, exactly. Only some 'workarounds' may give a litlle bit of dimming. Some people used the 21W Welch Allyn unit down to ~9W. At this wattage it had about the efficiency of an usual halogen bulb (~200-500 hours). There are different opinions if this damages the bulb or not.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>that the HID is a little more susceptible to damage than even incandescents.<HR></BLOCKQUOTE>

Yes and no. First there is no filament to break. But the small Welch Allyn bulbs are pretty small and are only supportet from one end. It would be easy to change that if there is enough demand from the customers.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
But it is the most efficient bright power source, ie lumen/watt. Is that right?
<HR></BLOCKQUOTE>

Fluorescent lights are even better. People made several good fluorescent lighst for caving, Doug Strait made his faumous 'incredible light' (I'm not shure about the name and will edit it later).

Urban Domenij, a Swedish caver who is developing (battery powered) fluorescent lighst as a profession, was working on one.

And the NevTek is still the best available one. I was almost buying one when I got my first ActionLight.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
As for Li-Ion batteries, where do you get them from and what sort of re-charger do you use?<HR></BLOCKQUOTE>

Inexpensive source are laptop computer power packs (sold on ebay). Depending on which exact chemistry, they are easy to cahrge if you don't need the longest life. Constant voltage with current limit and shutoff when current falls below a treshold.
You may also use camcorder powerpacks and use readily available chargers for them.
For the flat SAFT cells I like, I have a dealer in Germany (these cells have their discharge protection already built in). I'm still looking for a couple of high power cells for using them with a cordless rotary hammer (12V probably 12-15A). 8 (or 6) cells with 6Ah should do it, but I will not buy new ones.

The NevTek looks very interesting. However, I suppose that the fluorescents suffer from the same problem as LEDs, ie they don't focus well for distance throwing / spotlighting? Then there is the problem of the lamp tube being glass and therefore a little more fragile than LEDs to shock, and being a little more prone to internal damage if the batteries run low? That is why, despite being more efficient lumen/watt than LEDs, people still look at using LEDs for the robustness?

Am I on the right track?

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Steelwolf:
The NevTek looks very interesting. However, I suppose that the fluorescents suffer from the same problem as LEDs, ie they don't focus well for distance throwing / spotlighting? Then there is the problem of the lamp tube being glass and therefore a little more fragile than LEDs to shock, <HR></BLOCKQUOTE>

First: Doug Strait's light was the 'Ludicrous Light'.

You got it pretty well. Opinions among cavers are somewhat different. Some people think, a real isotropic (same brighness in all directions) light will be the best. A CB (ceiling burner) carbide light comes very close to it. And of, course a fluorescent tube.
But it is not only the 'throw' which is missing. If you light is bright enough, closer objecs are lighted so much that you cannot see too far, independent how bright your light will be (almost). You will need an additional spotlight anyway.
The usual 20° Nichia white LEDs come very close to the perfect light distribution, even the Luxeons are good (despite they have a narrower beam). You have enough 'spilled' light to feel comfortably and a bright enough 'hot spot' for the distant objects.

With fluorescent lights you need at least a 5W tube to get a serious and efficent light. If you are carefully you may dim it without any bad sideeffects (Doug Strait made a science out of it). To get the highest effiency and the longest tube lifetime you have to heat the both filament (not just preheat them), for each temperature and power setting with a different current. Nowadays uP controls could do it easily, but I know about no new developments.
The tubes are of course more fragile than a LED, but it is possible to make it rigid enough. A further drawback is the decreased effiency at lower temperatures (while LEDs increase their efficiency and brightness there, incandescents stay the same).

New LEDs will come close to fluorescents soon when comapred at lower temperatures.

part 6
emergency lights:

Should be:
small, lighweighted, long enough lasting, long shelf life.

A good solution is a Photon or one of it's clones. The Click-It turned out to be even more useful (at one third of the price). My personal favorite is currently the ArcAAA, as it is pretty easy to mount it to the side of the helmet with thick rubber rings or cable ties. And it has enough light for navigating the most caves. The IMG Infinity is too dim. It is actually only good for waiting in a rescue situation.
A constant light output is nice, but not mandatory. The light has to be waterproof (for long term storage) and lithium cells are preferred. Hopefully this lights will be carried around a long time before they get used (if ever).
But in practical underground life, the ActionLight users are the only ones who never needed an emergency light up to now (with the LuxBrite people coming close). OK, not exactly true: all the others have two main lights, so they have to use the second pretty regularly.
And when you use a Phton or similar, don't carry spare batteries! Take spare lights with you! The size and weight are negligible and changing batteries is nothing to deal with in an emergency.
And for the very unlikely case that you loose your hardhat, you should carry your emergency light somewhere else.
Don't think even about a generator powered light, they are of no use. Their mechanics does not last as long as the same weight in lithium batteries for the same power. The same is true for their shelf life. Don't forget that 'shelf life' for a caving emergency light means that it is carried around probably hundreds to thousands of hours (bumbing against walls etc.).

For an emergency light, the light colour is not so important. That means, you could use a cyan or amber LED light if you get more out of it.

I will try to make an emergency light out of a Tekna MonoLith or SplashLite and an amber Luxeon Star.

The Arc AAA's drawback is that it has no front lens and will therefore easy be filled up with mud and is almost impossible to clean under cave conditions.

Of course also the emergency light should have some possibility to mount it on the head or helmet.

When people ask me if I have three independent sources of light, I answer:

I have one candle and two matches, is that OK?