Marker light

I would like to build a marker light using the following components.
A soda bottle preform
An 18650
A 5mm led
I’m not looking for a lot of light, run time is the goal. Is there a single mode driver that will work for what I want to do. Low voltage shut down would be nice also.
I recently ran across these “preforms” and think they would make a great host for something like this, there cheap, water proof, and tough. Not quiet sure of the inside dimention but they’ll fit 2- 18650’s

How bright do you want this to be ? and how long of a run time you hoping to get ?

It really only needs to light up, something that shows up in darkness from say 500 yards. As far as runtime goes it would be nice if it ran for 2 or 3 days

What battery?
edit: I can read good.

any reason for wanting an 18650? Using a primary cell (single use) such as a CR123 would mean no LVP is required so you could suck every last bit of energy out of the cell, you could make a joule thief type circuit and probably get a few hundred days out of a single CR123.

You’re not marking something for navigation from the air are you? Cause that will require MUCH MUCH more brightness.

I just want to see my dock when I come back at night in my skiff. It’s rocky around there and you need to come in at a particular angle. I used to use one of those lights comercial fishermen use to mark crab pot floats, there a 2- d cell photo cell strobe but there kinda spendy and go through the batterys pretty fast . The reason for the 18650 is I can recharge them and there’s a lot of energy in a small package, but I could use eneloops ore something else if it makes it easer but it needs to be something off the shelf so to speak because I don’t know enough about drivers to build one

Ok after giving the joule thief circuit a look, it looks like a simple enough project, I think I’ll give that a try.
Is the toroid coil something I can pick up at radio shack or is there a size or value that I need to know?
I assume this circuit can’t use 18650 because the voltage is too high?
Can it use aa in parallel to increase run time?

A typical 5mm LED is happy (and quite bright) with I=20mA, and a Q=2500mAh cell can run that for t=Q/I=2500mAh / 20mA = 125 hours, i.e. 5 days.

Simple version: 18650, resistor, LED. Some rough low voltage not-really-protection: as the voltage goes lower, the LED will go darker and draw less current, draining the battery slower and slower.

More complicated version: 18650, MCU, resistor, LED; Still unregulated, but the MCU can monitor voltage and shut down the light (or start blinking when the cell is relatively low). Some beacon pattern might be handy actually to increase the runtime to weeks. Could even go to sleep when it's bright (day) to run even longer, requires another 2 components (LDR, resistor).

Even more complicated: 18650, MCU, 1*AMC7135, an old XR-E/XP-E/XP-G/XM-L etc. in a beacon mode; may also run for weeks. Could even go to sleep when it's bright (day) to run even longer, requires another 2 components (LDR, resistor).

I have built LED “glow” lights that run for over a year continuously on two AA alkalines, and with some mods it could be built to be a bit brighter and seen for a long distance and still run for 4 - 5 days on the same two AA batteries. (i modded a red LED bike light that ran for 11 days on two AA cells ( 264 hours continuous and the cells still has 1.27 volts after the 11 days) that had both flash mode and steady on mode.)

If I start out with the simple version I need only 3 parts?
18650, resistor, 5 mm led?
What resister do I need for this simple version?

The Princeton Tec Eco Flare is designed as a waterproof marker light. It will only flash, no always on mode, I don’t know if that’s a deal breaker, but other than that it will run for many hours on 2 AAA batteries. You can use Eneloops.

They Claim 500 hours run time.

DBAR, what components did you use to build the glow light that glow for over a year? Is there a thread about this?

Its the glow Light on the Steam Pipe Light i built for the 2nd BLF Contest here:

Though its noticeably dimmer now, its still glowing on my bedside night table since June 2013 on the same two AA cells i placed in it then.
I will replace the cells once its barely glowing, or the AA cells are at such a voltage that there may be a risk of then starting to leak.

Since it’s going to be an “at night” light…put a photovoltaic resistor on it…have it only come on at night…save ALOT of wasted energy

Check out this one guys infinity jar, with a super capacitor and encapsulated/weatherproofed…it could run for YEARS
https://www.tindie.com/products/rtpreppers/infinity-supercapacitor-solar-sun-jar-unit/

Those small 5vdc USB plugin deals with the small SMD 5050 LED’s, you could easily run 3-5 of those off that 200mA output straight in, if you look closely they usually have a voltage limiting resistor to cut down on the volts/current flowing to the emitters, a straight 3.3vdc would make them run nicely…and that should be plenty of light for a beacon)

Get that unit…get a mason jar(plastic one might even be better), frost the inside of it, then screw the lid on top of a boat dock pylon

Could something like this work http://www.mulelight.com/ It couldnt be too hard to make an epoxy+glow powder diffuser and then see if dr jones can make you a custom driver for that

Those are some very interesting lights, I doubt we get enough sun for the solar one, mostly dark rainy days for 6 months now and days getting shorter

Maybe put a timer on the light so it’s not burning when not needed.