LED Search Light

[aznsx]

Not to presume to speak for the OP, but I just reviewed post #1, and I believe the OP posted seeking help in selecting some flashlights for use by camping staff.

 

[bbrins]

Trust me, if they're going to scrutinize a purchase of flashlights, the idea of a thermal imaging drone with A.I. ain't gonna fly.

 

[bbrins]

Yeah, I guess we are getting a smidge off topic.

Dang. I rhymed and punned in that last post.

 

[aznsx]

Yeah, I guess we are getting a smidge off topic.

Dang. I rhymed and punned in that last post.

We'll forgive you - just this once.

 

[kerneldrop]

It’s acceptable and encouraged to derail when a thread is 6 pages.

 

[Fuzzywuzzies]

@TD-Horne Tom - I know there's a ton of information flooding (pun intended!) at you from all the helpful and enthusiastic folk here on CPF, but as I've followed this thread, I've spotted a couple of important things:

1. There are a lot of flashlight enthusiasts here on CPF, (heck that's what we're here for, right?) so of course most of us are going to gravitate toward high output lights and high density batteries and so on. That said, you may be asking a little bit much of what current technology - and indeed physics - can offer. @DaveTheDude 's recommendations are a brilliant balance of your requirements, and fairly realistic. If you want to go beyond them, be prepared to compromise on one or more of your original stipulations.

2. Correlating actual reality to the terms and example photos on the internet is extremely difficult. Lumens and Candela and so on are terms used to describe the apparent brightness of a given light in a certain circumstance, without actually going out in the dark and trying it, and are often conflated and misunderstood. For your needs, you don't have to do the geek stuff, but I think a super quick reconnaissance over the subject might help, as follows:


Essentially - and please fellow enthusiasts don't roast me too much here, I'm just making a point to help Tom - essentially Lumens refers to the total amount of light collectively spread across the scene in front of you. It has no bearing on bright and dark beam patterns, just the whole lot measured together. Candela refers to the brightness of the brightest point in beam pattern, usually right in the centre.

So you see, this means you could have two flashlights, both 200 Lumens, but one has a narrow beam that's super bright, and the other has a wide beam that's quite dim. Both are outputting the same amount of light, using the same energy and run the same length of time. But one will blind you up close, give you no peripheral vision, and be really good at seeing things in the distance. The other will be great up close, give you good peripheral vision, and be terrible at seeing anything beyond 10 feet, to present an extreme example for the sake of the point.


I'm a photographer, so this evening I grabbed four flashlights and set up a proper fixed exposure to show a decently realistic impression of comparative light outputs - see below.


The photos are:
Annotated photo 1 - Flood beam, note lumens and candela annotated
Annotated photo 2 - Standard beam, note lumens and candela annotated (A true "Spot" beam would be even narrower with virtually no peripheral light)
01- Elzetta Bravo Flood (Centered) 850Lu 1,915cd 6000K
02- Elzetta Bravo Flood (Diverted) 850lu 1,915cd 6000K
03- Elzetta Bones Standard (Centered) 850lu 12,036cd 6000K
04- Elzetta Bones Standard (Diverted) 850lu 12,036cd 6000K
05- Solarforce L2 (Centered) 830lu
06- Solarforce L2 (Diverted) 830lu
07- Solarforce L2 (Centered) 180lu
08- Solarforce L2 (Diverted) about 180lu
09- Solarforce L2 (Centred) about 25lu
10- Solarforce L2 (Diverted) about 25lu
11- Elzetta G-EDC-AA (Centred) 150lu 1,810cd
12- Elzetta G-EDC-AA (Diverted) 150lu 1,810cd
13- Elzetta G-EDC-AA (Centred) 30lu
14- Elzetta G-EDC-AA (Diverted) 30lu
15- Elzetta G-EDC-AA (Centred) 1.5lu
16- Elzetta G-EDC-AA (Centred) 1.5lu

I took two exposures for each mode on each light. All exposures are identical on the camera, and I've post-processed these from Raw to mimic reality as best as I can. The only real limitation is the human eye has a little more brightness in peripheral vision, and would adjust a tad to the very dim outputs, so they wouldn't look quite as black as my fixed camera exposure.

Disclaimer: These are all expensive lights (except the Solarforce) and most run on lithium rechargeable cells. They're all great SAR lights in their own right, but I only show this for the sake of accurate comparison for Tom's specific use case, so he can see what different Lumen and Candela ratings look like. Colour rendition and LED quality are topics for another day, but as other posters have mentioned, it makes a fairly significant improvement when searching for anything.

I hope this helps, Tom. All the best.


 

[Fuzzywuzzies]

...and the remaining photos.

 

[bykfixer]

It seems like what is being sought is not the initial spotlight for checking distance but for detailed work in small, precise grids like looking for clues to determine if the lost person went this way or that way. A small piece of cloth snagged on a thorny vine, a chewing gum wrapper, a mild foot print etc. An aid for when the sun isn't shining. Hence the request for a broadly dispersed even lighting tool to help knock grids faster.

Again, a COB light would be great for that.

 

[Poppy]

@Fuzzywuzzies
Thank you for doing this!


I'm a photographer, so this evening I grabbed four flashlights and set up a proper fixed exposure to show a decently realistic impression of comparative light outputs - see below.


So often when one watches a video presentation of a beam shot, it is obvious that the camera is auto adjusting its aperture thus giving a consistent appearance, and not truly depicting the difference.

 

[DaveTheDude]

To help keep the topic on track, and summarizing the discussion (at least to his point in the thread):

1. The use of alkaline cells is baked into the design limitations of the flashlight product search.
2. Alkaline cells have a discharge curve that unavoidably results in dimming during continuous use.
3. 3xC, 3xD, and 4xD configurations will last longer than multi-AA configurations, assuming the same current draw.
4. Search parties using alkaline cells will need at least one set of backup cells to meet search duration criteria.
5. The pack weight of backup alkaline cells will be an unavoidable consequence of using alkaline cells.
6. The purchase price of lights is a critical budget limitation.
7. The purchase price of lights is a critical budget limitation.
8. The purchase price of lights is a critical budget limitation.

9. Inexpensive, muggle-level aids to lost camper location (e.g. - whistles) are responsive to the problem.
10. Active location marking devices (e.g. - camper-worn locator lights or beacons) MAY be responsive to the problem.
11. Expensive, technically sophisticated and low-use tools are cool, but are not really responsive to the problem.

*********************************
Another Flashlight Recommendation. Keeping the above criteria in mind, and returning to suggestions for a cost-effective alkaline-powered flashlight that is responsive to Mr. Horne's search criteria, I offer another suggestion. My local Home Depot is at present deeply discounting its Defiant-brand flashlights through the end of March 2023. Of particular interest is the Defiant 3xC, normally about $30, now on sale for $10. At a $10 price it might be worth buying a few, and certainly worth buying at least one to check out its performance against the preferred flood beam criterion.

The Defiant 3xC is a three-emitter torch, producing a beam with a very wide hotspot, one broad enough to be reasonably classified as floody out to at least the first 50 feet or so from the emitter. The light has three output levels: 1200 lumens, 200 lumens, and strobe. It takes at least an hour of constant use at the 1200 lumen level before the dimming starts to be noticeable, and even than only at distance: objects within 25 feet are still clearly illuminated. (I keep one of these in my car's trunk kit, batteries stored separately.) To better preserve battery life, switching between the 1200 lumen and 200 lumen settings is simple; even a child of five can do it.

The light weighs 15.5 ounces with batteries. By comparison, the 2xC Mag-Lite ML50L (with batteries) weighs 11 ounces, and the 2xD Mag-Lite weighs 24 ounces. I've included two images for size comparison, below. The Mag-Lite 2D is on the left, the Mag-Lite 3xC is on the right. The second image is the Defiant's emitter configuration. Food for thought...

P.S. - Poppy had a comment about this light on a previous page that I missed. He astutely notes that the light's output WILL fall off during continuous use. The question for Mr. Horne isn't however does the light output decline, rather the question is does it decline too much to be useful to the search team. My personal experience with this light is that the falloff will not be damning, and that the ability to switch back and forth, from 1200 lumens to 200 lumens, as needed, will mitigate the inevitable decline in alkaline cell performance. Also, the inevitable decline in output will still produce illumination sufficient to clearly illuminate the scene out to 25 feet. To my knowledge, no hand-carried lights powered by alkaline cells will be able to sustain high output levels for hours at a time. The choice is how much decline is acceptable while still remaining useful for the intended purpose. 'Nuff said.

 

[TD-Horne]

So this may be my least coherent question yet but I have to know. Could I take something that would be considered a 2 D or 2 C size flashlight, such as a Maglite with a drop in higher powered emitter, with adapters if necessary, install 2 lithium rechargeable cells; If you'd like to see a huge smile make them Lithium Iron Phosphate cells; and an appropriate LED emitter and get some of what I've been hoping to find in the performance department. Could I then, having gone through 2 sets of rechargeable batteries, remove the now spent rechargeables, screw on a 2 cell extension tube, Install 4 Alkileak cells and run that same emitter with the 4 alkaline cells for some length of time. Initially the extension tube would be the carrier for the second set of charged LiFePH4 batteries to run the light for a second period on rechargeables. [If the rechargeables were LiFePH4 they would be a lot lighter than carrying Alkileaks.] Are any of the drop in reflector emitter assemblies for Maglites meant to be flooders? The underlying question is does the availability of extension tubes for Maglites open up any opportunities for making up a combination light that would give some effective level of brightness which would not quickly dim, in the neighborhood of 500 lumens in a 2 C or D form factor that could run at or about the same level of output as a 4 cell primary as it did as a 2 cell secondary. So the only thing would be to hold the Lumens close to constant and just add primary cells to the assembly to keep it running somewhat longer after the 2 sets of secondaries are drained. Is their anything uniquely useful in that approach. It seemed like if someone who really knows the available batteries and emitters would take a look at what could be fit into an erstwhile Alkileaks flashlight that would give it the performance desired in brightness while still permitting it to be run on readily available primary cell batteries when the available rechargeable batteries are exhausted.

Clear as mud right? Let me lay it out in list form.

• Start with a 2 cell C or D size flashlight that will except a drop in emitter of suitable brightness and that will run on 1 or 2 lithium ion rechargeable cell/s at an acceptable constant brightness.
  • In other words at a setting that will not quickly dim the light.
• add an extension tube to provide enough space for 3 to 5 Primary cells that could still power the emitter at some constant lumen level.
  • Extension tube holds second set of rechargeables to run emitter at the selected constant output.
• If second set of rechargeables become exhausted remove adapter sleeves if used, add extension tube to light, load needed number of best available primaries, resume operations.

If I were as familiar as many of you are with the emitters available and the battery dimensions, voltages, and amperage rates available I would know if this is feasible. I am not so I have to ask those that are.

Tom Horne

 

[TD-Horne]

I was wondering how do you search? As far as I can see, searchlights have basically a narrow beam to find something. A wide beam will illuminate some area ahead, but it will not penetrate into the darkest corners.
For example, I was taught to search with a lantern with a narrow beam - to break the perspective into squares and examine one by one square by square, without leaving the spot. Move to a new point - continue scanning from the beginning in the same way.

View attachment 41680

Also, looking at a wide area may be less effective than looking at many small areas, since the brain will instinctively be lazy to look at the entire surface and something may escape the eye. Although you can use a combined beam - first inspect everything sequentially with a narrow beam, then look with a wide beam, then check everything again with a narrow beam and again with a wide beam.

Did I understand correctly that the main goal is to find missing children?

Another live hack is to hang bells on each. On your feet or on your hands so that they ring when you move, then they will be very easy to find if they move

View attachment 41681

The remedies to the risks we perceive must be tolerated well enough by the children so as not to cause them to run away on purpose. Enough said?

Tom Horne

 

[alpg88]

So this may be my least coherent question yet but I have to know. Could I take something that would be considered a 2 D or 2 C size flashlight, such as a Maglite with a drop in higher powered emitter, with adapters if necessary, install 2 lithium rechargeable cells; If you'd like to see a huge smile make them Lithium Iron Phosphate cells; and an appropriate LED emitter and get some of what I've been hoping to find in the performance department. Could I then, having gone through 2 sets of rechargeable batteries, remove the now spent rechargeables, screw on a 2 cell extension tube, Install 4 Alkileak cells and run that same emitter with the 4 alkaline cells for some length of time. Initially the extension tube would be the carrier for the second set of charged LiFePH4 batteries to run the light for a second period on rechargeables. [If the rechargeables were LiFePH4 they would be a lot lighter than carrying Alkileaks.] Are any of the drop in reflector emitter assemblies for Maglites meant to be flooders? The underlying question is does the availability of extension tubes for Maglites open up any opportunities for making up a combination light that would give some effective level of brightness which would not quickly dim, in the neighborhood of 500 lumens in a 2 C or D form factor that could run at or about the same level of output as a 4 cell primary as it did as a 2 cell secondary. So the only thing would be to hold the Lumens close to constant and just add primary cells to the assembly to keep it running somewhat longer after the 2 sets of secondaries are drained. Is their anything uniquely useful in that approach. It seemed like if someone who really knows the available batteries and emitters would take a look at what could be fit into an erstwhile Alkileaks flashlight that would give it the performance desired in brightness while still permitting it to be run on readily available primary cell batteries when the available rechargeable batteries are exhausted.

Clear as mud right? Let me lay it out in list form.

• Start with a 2 cell C or D size flashlight that will except a drop in emitter of suitable brightness and that will run on 1 or 2 lithium ion rechargeable cell/s at an acceptable constant brightness.
  • In other words at a setting that will not quickly dim the light.
• add an extension tube to provide enough space for 3 to 5 Primary cells that could still power the emitter at some constant lumen level.
  • Extension tube holds second set of rechargeables to run emitter at the selected constant output.
• If second set of rechargeables become exhausted remove adapter sleeves if used, add extension tube to light, load needed number of best available primaries, resume operations.

If I were as familiar as many of you are with the emitters available and the battery dimensions, voltages, and amperage rates available I would know if this is feasible. I am not so I have to ask those that are.

Tom Horne

YEP it is doable, but you need old type 2D to use drop ins, new led models will not work, nor there are any extensions available for them, lumencraft sells 1 and 2 D extensions. C lights do not have extensions available afaik, C are half the capacity of D so runtime will be half using alkalines, aliso most drop ins are made for D, very few fit C

 

[alpg88]

About 15 -17 years ago, when only leds available were 5 and 10mm leds, first luxeon just came out, and was pretty weak, I converted big dorcy 6v lantern with 5 and 10mm leds, I took it camping, and it was a hit, it flooded entire campsite. By today's standards it is pretty lame, but back then it was way cooler than any flashlight available at the time.

 

[knucklegary]

@alpg88,, It's still pretty cool !

 

[desert.snake]

The remedies to the risks we perceive must be tolerated well enough by the children so as not to cause them to run away on purpose. Enough said?

Tom Horne

No, absolutely not enough. I'm sorry, I don't understand what the danger you perceive means? Does this danger have a name or is it some personal feeling that cannot be expressed in words?

How can children start running away if they are lost or are being looked for? Like a recent story with a tourist

Lake County Search and Rescue

October 21, 2021

At approximately 20.00 on October 18th LCSAR was called out for an overdue hiker on Mount Elbert. The reporting party reported the subject had started hiking Mount Elbert from the South Trailhead at 09.00 that morning, and had not returned by 20.00 that evening. Multiple attempts to contact the subject via their cell phone were unsuccessful. 5 LCSAR members deployed at 22.00 to search high probability areas on Mount Elbert, but did not locate the subject, and left the field at approximately 03.00 on the 19th. At approximately 07.00 on the 19th, a team of 3 LCSAR members began the search in a new area where hikers typically lose the trail. At approximately 09.30 the reporting party reported the subject had returned to their place of lodging. All personnel were out of the field by 10.00.
The subject stated they'd lost the trail around nightfall and spent the night searching for the trail, and once on the trail, bounced around onto different trails trying to locate the proper trailhead, finally reaching their car the next morning, approximately 24 hours after they'd started their hike. They had no idea that SAR was out looking for them.
One notable take-away is that the subject ignored repeated phone calls from us because they didn't recognize the number. If you're overdue according to your itinerary, and you start getting repeated calls from an unknown number, please answer the phone; it may be a SAR team trying to confirm you're safe! Finally, to Mount Elbert hikers, please remember that the trail is obscured by snow above treeline, and will be in that condition now through probably late June. Please don't count on following your ascent tracks to descend the mountain, as wind will often cover your tracks.

Do you give them pre-training on what they need to do if they get lost? For example, make creases on twigs / notches as they go, or scatter breadcrumbs or other small objects, or rubbing against trees so theoretical search dogs can find them.

I can understand that children may run away from rescuers or other people if they are mentally unstable or autistic. If you have an autistic camp, then that might make a difference. Recently there was a story, a small autistic child got lost in the forest - he moved away from his parents while picking berries. They searched for him for 1,5 days, it turned out that he was sitting 300 meters from the place of his disappearance in a bush and was silent, not reacting to rescuers. The dogs that sniffed it out helped.

Dogs, by the way, are very useful in finding lost people. As far as I understand, your camp is mostly voluntary. It is quite possible to talk to volunteers from animal shelters and dog handlers, maybe someone has dogs with search abilities, which they could give you free of charge for the duration of the trips and then take them back. Of the costs here will be only food for dogs.

 

[bykfixer]

So this may be my least coherent question yet but I have to know. Could I take something that would be considered a 2 D or 2 C size flashlight, such as a Maglite with a drop in higher powered emitter, with adapters if necessary, install 2 lithium rechargeable cells; If you'd like to see a huge smile make them Lithium Iron Phosphate cells; and an appropriate LED emitter and get some of what I've been hoping to find in the performance department. Could I then, having gone through 2 sets of rechargeable batteries, remove the now spent rechargeables, screw on a 2 cell extension tube, Install 4 Alkileak cells and run that same emitter with the 4 alkaline cells for some length of time. Initially the extension tube would be the carrier for the second set of charged LiFePH4 batteries to run the light for a second period on rechargeables. [If the rechargeables were LiFePH4 they would be a lot lighter than carrying Alkileaks.] Are any of the drop in reflector emitter assemblies for Maglites meant to be flooders? The underlying question is does the availability of extension tubes for Maglites open up any opportunities for making up a combination light that would give some effective level of brightness which would not quickly dim, in the neighborhood of 500 lumens in a 2 C or D form factor that could run at or about the same level of output as a 4 cell primary as it did as a 2 cell secondary. So the only thing would be to hold the Lumens close to constant and just add primary cells to the assembly to keep it running somewhat longer after the 2 sets of secondaries are drained. Is their anything uniquely useful in that approach. It seemed like if someone who really knows the available batteries and emitters would take a look at what could be fit into an erstwhile Alkileaks flashlight that would give it the performance desired in brightness while still permitting it to be run on readily available primary cell batteries when the available rechargeable batteries are exhausted.

Clear as mud right? Let me lay it out in list form.

• Start with a 2 cell C or D size flashlight that will except a drop in emitter of suitable brightness and that will run on 1 or 2 lithium ion rechargeable cell/s at an acceptable constant brightness.
  • In other words at a setting that will not quickly dim the light.
• add an extension tube to provide enough space for 3 to 5 Primary cells that could still power the emitter at some constant lumen level.
  • Extension tube holds second set of rechargeables to run emitter at the selected constant output.
• If second set of rechargeables become exhausted remove adapter sleeves if used, add extension tube to light, load needed number of best available primaries, resume operations.

If I were as familiar as many of you are with the emitters available and the battery dimensions, voltages, and amperage rates available I would know if this is feasible. I am not so I have to ask those that are.

Tom Horne

Feasible? Yes
Practical? No
At this point there is no defined "kit" for such a thing.

You could have someone 3D print a battery holder that is the same length as those alkalines stacked end to end and swap it out for the alkalines. Reload it as needed or as fresh rechargeables become available. Kinda like swapping out a pistol magazine.

See, now days the market is geared toward smaller and brighter. There was a time however when the "modern" search and rescue light started out as a 3D number by Bright Star, Dog Supply House, Rayovac and others where extension tubes were available in various sizes to turn a 3D into a 6D or with a couple of 1 cell extensions into a 5D, 7D or more.

You'd find those on eBay. Particularly Dog Supply House who built search and rescue lights in the 1950's and 60's. They're not set up to house a Maglite type drop in though as they used standand (at the time) bulb fasteners. Rayovac made a Sportsman version that had an optional leather shoulder strap.
All mentioned did however use glass lenses, metal reflectors and pretty solid copper parts that could withstand the heat of a typical 9 volt bulb. It's when the halogen was introduced that heat became an issue.

 

[Poppy]

@DaveTheDude
You make good sense.

P.S. - Poppy had a comment about this light on a previous page that I missed. He astutely notes that the light's output WILL fall off during continuous use. The question for Mr. Horne isn't however does the light output decline, rather the question is does it decline too much to be useful to the search team. My personal experience with this light is that the falloff will not be damning, and that the ability to switch back and forth, from 1200 lumens to 200 lumens, as needed, will mitigate the inevitable decline in alkaline cell performance. Also, the inevitable decline in output will still produce illumination sufficient to clearly illuminate the scene out to 25 feet. To my knowledge, no hand-carried lights powered by alkaline cells will be able to sustain high output levels for hours at a time. The choice is how much decline is acceptable while still remaining useful for the intended purpose. 'Nuff said.

Years ago there were many threads here discussing "Vampire lights" ie ones that would continue to run to very low levels and drain half used batteries.

I was thinking... what to do with all of those 1/2 to 75% depleted alkaline cells? Then it dawned on me, that (as I mentioned earlier) lumens are additive. So a light that has run down to 30% output, and is not quite useful for the task anymore, if a person had two such lights, he/she could hold them side by side and get an equivalent of 60% output, or thereabouts.

We always say around here "two is one, one is none" so... one should be carrying a backup light anyway.

If those 1200 lumen triple LED lights are available at $10 at a local HD store, I'd pick up a pair, if not more.

 

[Poppy]

As my friend @bykfixer said:

Feasible? Yes
Practical? No
At this point there is no defined "kit" for such a thing.

@TD-Horne
You are over thinking this, and I do appreciate your thought.

It would be much easier to get a 3 cell light. Load it with a spacer/adapter and a Li-Ion cell, and swap it out as necessary. One may carry a set of back-up alkalines, and just pull the adapter/spacer out of the way.

Here we have a Defiant Triple LED 3 C cell light that I use an 18650 cell with a wrapping of plastic from a cut up water bottle, and a 1 inch dowel cut to length, and drilled to accept a stove bolt cut to length as adapter/spacers.



A C cell light would be able to take either an 18650 or 21700 cell. It *may* be able to take a 26650 cell. I have 26650 batteries from two different manufacturers. My C cell light can take a battery from one manufacturer, but not the other. The dimensions are off by a mm or two. A D cell light could fit any of the three mentioned above without a problem.

 

[bbrins]

Maglite offers an 18650 adapter kit for the ML50L 2 cell light, there are also 3D printed adapters available for 18650 and 21700 cells for two and three cell lights. If you want to go with lithium cells, I'd stick with a single protected cell. Two backup 21700 cells in some kind of case probably take up about as much space as 3 C cells. If you go this route, I'd do all of the charging back at the main camp so it could be supervised. It would also be good to have supplies on hand to re-wrap cells.

One of these adapters, or something like Poppy posted above would leave the light unmodified and allow someone to just simply pull out the adapter if they want to just run regular alkaline C cells.