LED light as a "beacon"

[hpcbmw]

Hi, I'm not an electronics wiz, but am pretty handy at making stuff. I attended a little camping party in the Nevada desert this fall with about 20k people. An RV near us had a bright green light attached about 15' above his motorhome that served as a beacon. We could see it from over a mile away, and it helped us find our way home each night. I'd like to make one of these for next year to find my way home. I never got around to asking the neighbor how he made his beacon.

Here is what I'm thinking: 2 10watt green LED lights, attached attached to a telescoping pole attached to my RV. This would be powered by a 75amp hour 12v deep cycle battery, charged by a 150w solar panel. The lights would be mounted back to back, so could be seen from most angles.

A techy friend ran the numbers and believes that the 12v battery and 150w solar setup should be sufficient to run this 12 hours each night, if not 24/7. If I've missed something on this, please let me know.

I'm looking for input on how bright a 10w LED light would be. Could it be seen from a mile or more away in the desert? Any suggestions on where on the web is a good place to find such a light? My techie friend said I might have to put the LED into epoxy and affix a heat sink of some sort.

Thanks!

 

[Stefano]

In the past I have read a very similar story but in that case a Fenix lantern with red flashing light was used, but I don't remember if it was the old CL25 or the new CL26R.
I remember that some Nitecore flashlights (but also Zebralight) have a nice Beacon function but you don't have 360° degree light like a lantern.
A curiosity, the green light above the camper was steady or intermittent?

 

[LEDphile]

I'd be looking at boating lights for this - white beacons rated at 2 nautical miles with 360 degree visibility are readily available, with red and green options also available if you dig a bit (or are willing to put together something made up of multiple directional sources).

Power requirements are typically only a few watts for the LED variants.

Something like this: https://www.hellamarine.com/en/prod...-pro-all-round-green-led-navigation-lamp.html

 

[DaveTheDude]

If you decide against building your own beacon assembly, CountyComm offers a D-cell powered 360-degree Landing Light Strobe (70 flashes per minute, at a claimed 450 lumens). Veracity of the company's claimed lumen output notwithstanding, even a 250-lumen strobe function would be noticeable at a distance in a flat, open environment. As of October 18th, the light is offered at $49.95.

I have one of CountyComm's 1xAA "pocket" strobes that I carry as an emergency beacon while backpacking. The AA version is advertised as producing a 350-lumen strobe, and although I haven't measured the lumen output, I can confirm that the AA strobe is easily and immediately visible at one-half mile (0.8 km), without any ambiguity whatsoever: you know that you're viewing an intentional signal light. I suspect that the D-cell version will be even more easily seen, and likely at greater distance, too. Just clamp it to a pole and hoist away.

Finally, the company advertises a strobe runtime of 450 hours on a fresh cell. Your belief system may or may not allow you to accept that claim at face value. Assuming you possess a more skeptical mind, I note that even a 50-hour strobe runtime would allow you an ample time buffer for a fresh battery change.

Did I mention it's dust proof? Le us know what you decide. And as with almost everything related to illumination projects, please post a few photos of the final project, especially in situ.

 

[hpcbmw]

Thanks for the great input. Stefano, the light was a steady green. It did not look like something commercially bought, but i only saw it from 40' away.

I'd really prefer to build my own, but you guys gave me some pretty good and reasonably priced options. Anyone know if a 10watt LED can be seen from a mile away?

 

[lightfooted]

Since LEDs don't work the same as incandescents it is kinda hard to say for sure since it COULD be an old LED from 10 years ago that just sucks down the power while only providing fifty lumens or so. It probably would be...but without specs and all it will be hard to give you any feedback.

 

[Stefano]

Thanks for the great input. Stefano, the light was a steady green. It did not look like something commercially bought, but i only saw it from 40' away.

I'd really prefer to build my own, but you guys gave me some pretty good and reasonably priced options. Anyone know if a 10watt LED can be seen from a mile away?

A colored light is best seen in an area where there are other lights because it stands out from others.
But green and red LEDs generally have a lower efficiency than traditional LEDs, if you are looking for maximum power and long-distance visibility, perhaps a traditional LED would be better.
I am not a sailor but I seem to remember that navigation lights have a traditional light.
Colored lights are used in maritime beacons to indicate particular points (red for the left side of the harbor, green for the right side)
A warm light then is best seen in fog or rain (just a thought)

 

[LEDphile]

A colored light is best seen in an area where there are other lights because it stands out from others.
But green and red LEDs generally have a lower efficiency than traditional LEDs, if you are looking for maximum power and long-distance visibility, perhaps a traditional LED would be better.
I am not a sailor but I seem to remember that navigation lights have a traditional light.
Colored lights are used in maritime beacons to indicate particular points (red for the left side of the harbor, green for the right side)
A warm light then is best seen in fog or rain (just a thought)

What do you mean by "traditional LED"? Red and green LEDs both predate white LEDs (by a couple decades), and while the radiometric efficiency of white LEDs is greater than green LEDs, it's on par with red. But radiometric efficiency aside, a direct emission red or green LED will almost always be more efficient than a white LED with a filter to change the color

I'd really prefer to build my own, but you guys gave me some pretty good and reasonably priced options. Anyone know if a 10watt LED can be seen from a mile away?

Visibility at distance is a function of the intensity of the source (candela in the direction of the viewer), the size of the source, and the background the source is viewed against. But given that there are commercially available LED beacons rated at 2 nautical mile visibility (at night, viewed against the dark background of the night sky and the sea) that draw less than 2W, and that a 10W incandescent lamp is used in some of the traditional beacons with the same rated viewing distance, a 10W LED source should be viewable at a mile at night.

 

[TechGuru]

Lots of pre-made stuff to choose from:

https://www.grainger.com/search/fleet-vehicle-maintenance/vehicle-lighting/exterior-vehicle-lighting/vehicle-strobes-and-beacons

https://www.grainger.com/search/safety/safety-alarms-and-warnings/strobe-and-flashing-lights

 

[pumps]

If you decide against building your own beacon assembly, CountyComm offers a D-cell powered 360-degree Landing Light Strobe (70 flashes per minute, at a claimed 450 lumens). Veracity of the company's claimed lumen output notwithstanding, even a 250-lumen strobe function would be noticeable at a distance in a flat, open environment. As of October 18th, the light is offered at $49.95.

I have one of CountyComm's 1xAA "pocket" strobes that I carry as an emergency beacon while backpacking. The AA version is advertised as producing a 350-lumen strobe, and although I haven't measured the lumen output, I can confirm that the AA strobe is easily and immediately visible at one-half mile (0.8 km), without any ambiguity whatsoever: you know that you're viewing an intentional signal light. I suspect that the D-cell version will be even more easily seen, and likely at greater distance, too. Just clamp it to a pole and hoist away.

Finally, the company advertises a strobe runtime of 450 hours on a fresh cell. Your belief system may or may not allow you to accept that claim at face value. Assuming you possess a more skeptical mind, I note that even a 50-hour strobe runtime would allow you an ample time buffer for a fresh battery change.

Did I mention it's dust proof? Le us know what you decide. And as with almost everything related to illumination projects, please post a few photos of the final project, especially in situ.

That little CountyComm 1AA pocket strobe is cool. I sometimes work on an airport and all vehicles moving on the ramp side MUST have a blinking strobe visible at all times. Something like that might work?

 

[knucklegary]

Lightman (older xenon model) strobe, and are designed for aircraft landing zone markers. Powered by 3x AA. Their new LED model, however, do not have the strobe option

 

[Lynx_Arc]

From what I'm seeing here I don't think a battery powered flashlight is going to suffice for a constant output but a quick thought had me thinking you can likely buy LED light bulbs at 12v and in colors at 120v and maybe find a colored one or use a white one that is dyed/painted over the wanted color. If you use a 120v inverter you can easily find colored LED bulbs at that voltage. If you have a 150W solar cell for 8 good hours of light a pair of 16W bulbs on an inverter with losses lets say would take about 50 watts of power and should run for 8-12 hours assuming you get 75 watts per hour of sun recharging the battery. The 75AH is about 800 watts or so and fully charged could run the bulbs for 16 hours but would need at least 6 hours of full sunlight to recharge if not 8-10 hours. I guess you could find a low current 12V timer to turn the inverter on/off at the appropriate times.