Third source of light

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Third source of light

Postby johnf93 » Sep 15, 2014 6:14 pm

What does everyone carry as their third source of light? I was taught that it should be different from the other two sources, generally meaning not battery powered. Right now, I carry a glow stick and a candle with waterproof matches. I'm open to suggestions!
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Re: Third source of light

Postby Carl Amundson » Sep 15, 2014 8:12 pm

Yup, I carry 3 sources of light. All are headlamps and I also carry extra batteries for the lights.
I go underground for days at a time on project work. Redundancy is very important.
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Re: Third source of light

Postby caver.adam » Sep 15, 2014 9:13 pm

I've never heard the "not battery powered". My primaries use 18650 batteries, which no one else in my group uses, so my backup in my pack is an apex that uses AA batteries so I can always share batteries with my group members if needed.

Also, be careful with glow sticks if you are rough on your pack. Glow sticks work when you break the glass vial in the center (you hear the snapping sound). It doesn't matter if you open the package, only whether you break that glass vial. It would suck to plan on having a glow stick that's been in your pack for years only to find out it doesn't work.
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Re: Third source of light

Postby johnf93 » Sep 16, 2014 12:32 pm

@ Caver.adam
When I mentioned not battery powered, I meant that someone should not have all three sources using battery power. I've been thinking about the logic behind it, and I can't really see why it would matter. It was what I was taught. Maybe it mattered more pre-LED and lithium ion battery days, when there wasn't a super low flashlight setting? I was just interested in what people use for their back up light. And good point about the glow sticks; I keep mine in a cigar tube for a little extra protection.

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Re: Third source of light

Postby snoboy » Sep 16, 2014 1:21 pm

Myself, I actually try to have all my light sources compatible. At this time I have settled on AA batteries, and all my lights use them.

My thought is that the lamp is likely the weak spot. If it dies, then I can use it's batteries in my backup. Of course there is am candle in my pack also, but that is more for heat than light.
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Re: Third source of light

Postby jharman2 » Sep 17, 2014 9:29 am

I have a few personal considerations regarding backup lights.

1. You need a total of 3 light sources that are sufficient to "cave" on. You do not want to attempt to exit any cave on a glow stick or a candle. Trying to do that is likely to precipitate another emergency.

2. The 2nd source of light should be as bright or nearly as bright (75%) as your primary. Ideally these are the same lamp so parts and batteries can be interchanged if necessary.

3. Two light sources must be mounted on the helmet, or one on the helmet and one around your neck.

My kit consists of a helmet mounted STEN and a helmet mounted Zebra 18650. I keep a spare STEN and battery in my pack. That may sound like overkill, but I would hate to abort a multi-day camp trip because my primary lamp failed and I only had two old Tikkas for backup.
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Re: Third source of light

Postby caver.adam » Sep 19, 2014 9:17 am

I like the idea of a cigar tube for the glowstick! Thanks for that one.
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Re: Third source of light

Postby Lava » Sep 22, 2014 11:42 am

jharman2 wrote:I have a few personal considerations regarding backup lights.

1. You need a total of 3 light sources that are sufficient to "cave" on. You do not want to attempt to exit any cave on a glow stick or a candle. Trying to do that is likely to precipitate another emergency.

2. The 2nd source of light should be as bright or nearly as bright (75%) as your primary. Ideally these are the same lamp so parts and batteries can be interchanged if necessary.

3. Two light sources must be mounted on the helmet, or one on the helmet and one around your neck.

My kit consists of a helmet mounted STEN and a helmet mounted Zebra 18650. I keep a spare STEN and battery in my pack. That may sound like overkill, but I would hate to abort a multi-day camp trip because my primary lamp failed and I only had two old Tikkas for backup.


I just wrote the chapter on lights for the upcoming new edition of the NSS' Caving Basics book, and essentially agreed what you said here. However, I would say that you do need two lights on your helmet so that you can turn the second one on if the first one fails while you're in a precarious position - a light dangling on the neck will probably not be of much use to you if you're in the middle of a climb when the first light fails. I also said that the third light doesn't have to be bright at all, that it should be long-lasting but only bright enough to get you safely out of the cave. I can see the benefit of modifying that stance In the case of a multi-day camp trip though.
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Re: Third source of light

Postby potholer » Sep 23, 2014 6:04 am

I'd certainly go along with endurance over output for a third light source.

I currently have main, backup(secondary) and third lights using different power sources, but I don't see that as a particular problem since I can easily carry spare AA/AAA cells for the backup and third lights, the backup and third lights should each be capable of getting me out from most places I'm likely to be on a single load, and I have compatibility with other people I cave with - pretty uniformly the same main, with their other lights also being AA or AAA powered.

Regarding helmet mounting, since I can't easily mount a second light on the helmet front alongside my large main, I'd have to sidemount a permanent secondary light, and the awkwardness of that in tight spaces and the chance of damage to or even loss of the light makes having a small headtorch around the neck seem a better and overall more reliable option, as well as being more convenient for underground camping, etc, and for surface use.
I dare say that if I had to, I could turn on a neck-worn headtorch or pull out and mouth-hold the light on my penknife cord sufficiently to get up or down any free-climbs I'm likely to be doing in the highly unlikely event of spontaneous main light failure.

As for secondary light output, since I started using proper LEDs, I don't think I've ever bothered upgrading my main light for anything less than a doubling in lumen output, but those upgrades were more because I could than out of any need, and the light I was using one trip didn't suddenly become unacceptable for happily caving on the next trip just because I had chosen to upgrade.
As things are, had I made a point of always having a secondary light 75% as bright as my primary, I would currently be on my fourth secondary light in a decade, having never used the first three as backups, and not expecting to use the fourth either.
As long as someone isn't annoyingly walking right behind me with a bright light on max, I could cave quite well with significantly less light than I currently have.
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Re: Third source of light

Postby jharman2 » Sep 23, 2014 10:28 am

Lava wrote:I just wrote the chapter on lights for the upcoming new edition of the NSS' Caving Basics book, and essentially agreed what you said here. However, I would say that you do need two lights on your helmet so that you can turn the second one on if the first one fails while you're in a precarious position - a light dangling on the neck will probably not be of much use to you if you're in the middle of a climb when the first light fails.


This is a very good point, and exactly why I don't neck carry my backup. I see many folks with a neck lamp as a backup and have always assumed they may be worried about being without light if they somehow lost their helmet. Loosing a helmet seems like it's quite unlikely.

Lava wrote:I also said that the third light doesn't have to be bright at all, that it should be long-lasting but only bright enough to get you safely out of the cave. I can see the benefit of modifying that stance In the case of a multi-day camp trip though.


The beautiful thing about modern LED lamps, even the less expensive ones, is that you can have both runtime and decent output. A $60 AA Zebra and a single AA battery on low will last for days!
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Re: Third source of light

Postby Lava » Sep 23, 2014 3:12 pm

jharman2 wrote:I see many folks with a neck lamp as a backup and have always assumed they may be worried about being without light if they somehow lost their helmet. Loosing a helmet seems like it's quite unlikely.


I happen to know someone who turned off their light, took their helmet off, set it next to them for a rest and then promptly lost the helmet in the dark for 5 minutes. They were sitting on the balcony of Fantastic Pit in Ellisons Cave! The individual had to crawl around gingerly while looking for it to avoid the edge! They were nice enough to report the incident on Tag-net as a lesson to others, and the story always stuck with me. So it can happen, and I did recommend in the chapter that it's better if your third light is somewhere on your person or even in a pack - somewhere else where you might be likely to find it that's not on your helmet. But I agree, the odds of this happening are incredibly small and I think just recognizing that losing your helmet is a possibility is probably enough to prevent you from ever losing it.
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Re: Third source of light

Postby potholer » Sep 23, 2014 4:02 pm

jharman2 wrote:This is a very good point, and exactly why I don't neck carry my backup. I see many folks with a neck lamp as a backup and have always assumed they may be worried about being without light if they somehow lost their helmet. Loosing a helmet seems like it's quite unlikely.

I dare say it is unlikely for any given individual, but then I guess having a spontaneous light loss on a climb is also unlikely, assuming someone is using a proper light without a tendency to peril-sensitive failure.

I did come close to dropping a helmet once or twice after I finally moved to fully helmet-mounted lighting after a *long* time using remote-generator carbide and (even longer ago) waistmount electric, since I'd become accustomed to having a helmet which was fairly securely attached to me by pipe or cable, and which could be removed/replaced for balaclava/hood placement/removal even while on pitches without particularly worrying about dropping it.
Now, if I need to remove my helmet where there's a chance of dropping it turning out badly, I make sure to clip a cowstail through the Y strap to keep it secure.
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Re: Third source of light

Postby Lava » Sep 24, 2014 11:34 am

potholer wrote: having a spontaneous light loss on a climb is also unlikely, assuming someone is using a proper light without a tendency to peril-sensitive failure.


Having come of age in the in the bulb era of caving, I've experienced more spontaneous bulb burnouts than I can possibly remember, and during all kinds of situations - climbing, on rope, hopping boulders, etc. So you'd be hard pressed to persuade me to take that second light off of my helmet. Aside from bulbs, I've also had electronics fail and batteries die. I'd agree that modern lights are an order of magnitude more reliable, but from reading these and other forums plus talking to other cavers, I know of failures in Sten lights, Zebralights, Sparks, El Speleos, and Scurions. So I think it's far more likely to happen than you are implying.
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Re: Third source of light

Postby potholer » Sep 24, 2014 5:22 pm

Lava wrote:
potholer wrote: having a spontaneous light loss on a climb is also unlikely, assuming someone is using a proper light without a tendency to peril-sensitive failure.


Having come of age in the in the bulb era of caving, I've experienced more spontaneous bulb burnouts than I can possibly remember, and during all kinds of situations - climbing, on rope, hopping boulders, etc. So you'd be hard pressed to persuade me to take that second light off of my helmet. Aside from bulbs, I've also had electronics fail and batteries die. I'd agree that modern lights are an order of magnitude more reliable, but from reading these and other forums plus talking to other cavers, I know of failures in Sten lights, Zebralights, Sparks, El Speleos, and Scurions. So I think it's far more likely to happen than you are implying.

I'm not making recommendations for others, just talking about my experiences and my choices based on what I know of my system.

Even in the old days I had hardly any electric light failures, but I normally used a non-halogen bulb in my Laser headset to back up my carbide, and those bulbs seemed pretty durable, not that I tended to use the electric except in wet/windy places since the carbide was reliable if properly maintained. I did have a cheap 2*AA flashlight and then a mini Maglite as third lights, but I'm struggling to remember using either of them except as loan lights to other people. I did sidemount the Maglite for a while, but only because if I carried it hanging in my personal gear bag the bulb kept falling out of the holder.

Also, I'm in an unusually good position to know how reliable my main light is since I made it, a decent number of other people I know use one, and partial or complete failures would very likely be brought to my attention. It was built with reliability very much in mind with worthwhile redundancy within a beam driver, and completely separate drivers for the two beams so the business end is effectively two lights already. The weakest point is the battery connector on the end of the (heavy duty) power cable into which various battery packs or AA holders plug. Chances are that if that did fail suddenly it would be at battery change, not when in use when it's under no mechanical stress. I'm only aware of a failure there happening once, and that was bodgeable in the field to a usable state.

However, even if that wasn't the case, if I expected that failure of an off-the-shelf light was going to be as rare as even every 2 or 3 years, let alone longer, that'd still make me reluctant to helmet-mount a backup if the only practical mounting places would expose it to meaningful mechanical abuse.
In such a situation, if I could sensibly front-mount something like my ZL backup, I'd consider it, though I do like solid mounting rather than things with headstraps, and solid mounting the ZL would probably make it at least more awkward for me to use it for other things, including as a helmet-off light while camping underground.

Certainly, for someone who has no idea how reliable their main is, there's an argument for at least starting off with a backup instantly ready on the helmet, and these days, depending on the main light's characteristics there could be an argument for having a helmet-mounted backup as a possible complement to the main, providing a useful beamshape and/or output which the main light lacks.
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Re: Third source of light

Postby CaverCSE » Sep 24, 2014 7:49 pm

Another caver here who lived through the bulb era of caving. I can still remember the 30min repair your light breaks we'd have to take during our cave trips. I had to repair my light probably every other cave trip until I started making my own lights which had very thick vacuum cleaner cord and better connectors. I got in the habit of carrying at least two lights on my helmet and one around my neck.
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