Finally, every inch of this long light is contributing to projecting photons. The finished light looks completely stock on the outside, except for a dedomed xml2 and AR lens.
Distance to the pine tree is about 250 feet. The tree is about 70 feet tall. It looks close to house, but it about 150 feet behind the house from the perspective of where the picture was taken. The emitter is just a touch too far behind the reflector when the below picture as taken (was about 284kcd at the time). Pictures are slightly darker than real life. Mouse over is Stanley 1M Series Lithium Ion Spotlight (54kcd unmodded):
The build is almost finished. It holds 3 unprotected cells (18650) but can run on 1 or 2 cells too. So it can run on Li-ion, Lipo's, Ni-mh, Ni-cad, etc. 4 AA's fit without a spacer. The nice thing with 3 cells is that the individual cells don't have to work very hard to provide 7 amps. So high performance cells are not required.
One of the cells passes through the switch housing. It uses a very short tail spring. The light has about $30 in parts as follows:
- DST $12
- Manafont 3T6 driver $6
- Dedomed XML2 U2 1A on Noctigon $6
- AR Lens $4
- Trim Pot (Resistors would be cheaper, but I didn't that any near the size on the drive)
- 3/4"Copper coupling (I think $1. Used the cheaper ones for HD)
- Misc supplies
I did also fry 2 xml2 emitters being careless in a rush late one night, but they are not physically part of the finished light. Right now running about 7 amps to the emitter and getting about 300kcd (has measured as high as 319kcd). Not bad for a budget light.
Tail current with 3 cells, charged to 4.15 volts resting, is:
High - 2.9 amps
Med - 1.25 amps
Low - .3 amps
It is handling the heat well. No hint of angry blue in the beam. This light handles an MT-G2 at 6+amps. So this is not a surprise.
Some Build Details:
Unfortunately, the DST pill has too narrow a driver bay and the walls are not thick enough to bore out for the Manafont 3T6 driver. So the following was done to beef up the pill's heat sinking and to accommodate the 3T6 driver:
- Lopped off the driver tower
- In the hollow portion of the remaining pill, pressed in 3/4" aluminum bar stock
- Drilled a hole through the pill and bar, and pressed in a 3/8" copper bar stock
- Counter sunk the back of the pill to add a new driver bay. Counter sink includes a 1/16" grove around the parameter to press the below 3/4" copper coupling into (overkill).
- Cut a short piece of 3/4" copper coupling and split lengthwise to open up diameter. Also cut a copper disk to press into the split 3/4" coupling.
- Used silver bearing solder to reflow the new driver bay to the copper bar. Also, reflowed an xml Noctigon base on the top side of the pill.
This is a pic of the pill assembly before the reflow. The copper coupling looks beat up because it is a reject from another project. Just happened to be about the right size.
A simplified version of the above could be made if one didn't want to drill, etc. I noticed some thin aluminum tent tubing fits snugly over the driver tower. The tower could be cut short and then the tent tubing would press over it. To hold the driver, a 3/4" copper coupling could be inserted in the tent tubing. Not as secure, but should do.
The split in the driver bay will allow easy adjustment current to the emitter via a trim pot. Stole this idea from RaceR86's T13 mod. The driver bay is solid and will not be going anywhere. Stress tested it several times. The driver board will break before damage to the pill happens. The switch section screws up around the lower portion of the driver bay. Covers the lower portion of the driver bay.
Here is the driver fitted be soldering and filing down to the size of the pill.
The trim pot really is accurate at dialing in current in this driver. Just don't crank it all the way up like I did and fry an emitter. I did start out lower, but got impatient adjusting. As can be expected by the specs, most of the trim pots range is not used in this application.
This driver gives rock solid current delivery with both 2 and 3 cells. I got no differences in emitter current with stock resistors and also with trim pot turned up to 7amps using 2 and 3 cells.
Also sanded of the anno in the ledge that is in the DST head that the pill screws down against. Also rapped the threads in copper tape. Really snugged up the fit. Both of these mods help facilitate heat sinking to the head and exterior fins. I copper taped all the DST threads.
Here is the preliminary quick-and-dirt "tail spring". It is equal to a very strong spring and provides a very good connection. It works real good right now because the light is currently a twistie. I think I will stick with this same design, but make a nicer version.
This blurry shot shows were the cells sit in the tube. There is no driver spring. The tail cap screws all the way down.
Switch (Sorry for the sideways pictures):
There are more switch pictures at Post 53.
