MtnDon
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# Posted: 30 Jan 2016 08:03pm
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My latest "just because I want to" project. This is not yet completed so I am taking a certain risk in displaying it, but what the heck I am full of confidence. ;)
In the world of modding flashlights the 'light we begin with is known as the host; the shell without the LED, without the electronics. Here is the project host, a Chinese manufactured kerosene lantern purchased at the local Wal-Mart for $5.62. The idea is to "LED" it and power with an 18650 cell and keep the appearance as true to a traditional kerosene lantern as possible.
It is about 10" high to the top of the chimney with a base diameter of about 4 3/8 inches. Black paint finish on some sort of magnetic grade of steel. A glass globe.
For those who have never messed with kerosene lanterns before here is how the globe assembly is made to swing away. The burner and wick unit is removable.
I got ahead of myself and forgot to take some pre-assembly photos.  I had already soldered the MCPCB to the end of the copper tube and cemented the ring in place when I remembered. So the detail on that assembly is limited.
The copper tube is standard ½" plumbing pipe. A copper ½ to ¾ adapter is glued in place over the emitter end with artic silver, a heat resistant and heat conductive epoxy. The tube will be shortened for final assembly.
I had an accident, so the emitter ended up being de-domed. [the silicone dome fell off. That makes the light output warmer among other things] Too much heat when I soldered the emitter star to the end of the tube. That's okay as I wanted this light color to be very warm. The Cree XM-L2 emitter (led) is on a Noctigon 16 mm MCPCB. It is a T4 bin and a 7B3 tint (3000 -3125 K). The LED being recessed a bit in the copper adapter also warms up the light output. I have run the LED using an old driver and like the light color. That 26 mm driver is too large for this project.
I have a Qlite 7135*8, 3.04 amp, 17 mm driver with guppydriver firmware on order that I'll be using. [A driver is the electronics that takes battery/cell power and makes a range of brightness's available.]
The aluminum heat sink is from Fasttech (Chinese seller). It is rated for 3 watts, so may not be enough when the LED is run on high. I hope some of the heat transfers to the lantern body and then the air. We'll see what happens. It had an 11 mm center hole. I bored out the center to 5/8" and honed it to be a snug fit when the copper tube is inserted. There is a tapped hole for a 4/40 set screw. A silicone diffuser will be used over the copper adapter.
The lantern will be powered by a single 18650 cell. (An 18650 cell is a lithium ion cell 18 mm in diameter and 65 mm long. (0.70" x 2.6"), much like the cells that make up the battery pack in a Tesla car. 3.7 volts. The one I plan on using has a capacity of 3500 mAh.)
The first mod to the lantern was to cut the wick shield hole out to allow the silicone diffuser to pass through. The globe lifter bail had to be removed to make this work. That's okay as we no longer need to lift the globe to light with a match.
Here's a trial fit with the heat sink and LED tube assembled and the unit mounted to the lantern. The heatsink is a nice fit in place of the standard wick holder mechanism.
So that is where I'm at today. I should have the driver in a few days. Once it is wired in I'll take a few photos. A longer delay will be waiting for the switch as it is coming from China, probably two weeks away. In the meantime I can work on fitting the cell holder inside the base and figuring out how to build in a charger board.
More to come as I progress.
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