Re: Viewpoint LED conversion
I thought that these might be of interest. This is for the newer Bullet Marwi MR11 lights so not quite on thread, but for anyone googling this forum for Marwi or ViewPoint, it will work.
The inside of these bullet bodies is a 1" column and 3/4" truncated cone. The anodizing was sanded off and the surface polished for better contact and heat transfer. For those interested google EL34, he has a limited supply of either shape.
For my first one, I decided on a removable (easy to mod) pill setup. The pill is a 1" Mueller copper pipe cap polished on the face and ground and sanded down by about 1/16" around the circumference and cut to about 17/32 deep using hand tools and a bench vise. It has a 7/16" (about) deep copper 1" to 3/4" reducer soldered in the backside to improve the thermal path to the lining. This reducer has a 1/8" wall and a lot of mass. I am not too fussed about weight as this light isn't going on my helmet, but heat is the enemy.
The lining is a 1 1/4" Mueller union with pressed-in shoulder where normally, two pipes butt. Stock, it is 2 1/8" long and has a 1/16" wall. The shoulder was used as a fore-aft stop for the pill. The union needs to be shortened by at least 5/8" so there is some freedom in placement of the shoulder in the light body. (This extra length can take vise marks, then be cut off.) Likewise, the groove in the pill/pipe cap can be closer to the front or back. The lining was reduced in thickness to a bit more than 1/32" by grinding inside and out and the shoulder was reduced in height to allow for an easier to make shallower groove in the pill. To shrink the union, 3/4" was cut out of the bottom side in line with the center of the mounting cut out in back. The rear of the lining has a cutout for the mount, and nine slots to allow the fingers thus formed to make a cone shape. The slots must be recut until the desired shape is accomplished. Much fitting, regrinding, refitting etc. Cottage industry prototyping at its best!
The LISA2 lenses are 6.8 mm and the XP-G R5 10 mm MCPCBs are 1.5-2 mm thick (awaiting delivery, and sit did not show exact thickness) so the groove was made accordingly. I am using a copper wire spacer in front of the liner for adjustment.
Here the heat sink is installed, for a test fitting of insulated mounting ring and the latest Taskled bflex. It shows the fingers of the lining in the cone part of the light body. Clearance is needed for the mount, so the fingers can't extend all the way back. The assembly is a tight fit requiring a pipe clamp to compress the sleeve which wants to spring to a larger size (good for body-sleeve contact once in). Removal requires the shoulder of the body be placed against wood blocks with room below for assembly to fall out, and a 'punch' made of a deep well socket and a moderately smartish tap or five. So yeah, it's snug.
Here it is in full test fitting (minus 3 XP-G's, LISA-2's, wiring, switches, status LED and the billed hoods I want to test for a low beam).
You can just see the 'almost centered' hole at the 11:00 o'clock position that I used for a bolt to spin the pill on my drill and which will now be the pass through for the LED leads. The darker rim is the remaining rounding of the cap to the sides of the pill. The wire spacer and the 9 mm of lining are clearly visible. Troutie figures about 1300 lumens for his 6 XPG R5's at 1 A with all losses considered. so each of mine should be about 650 lumens at max, a bit more than the MagicShine, but with better run times. Each can be as much as 30% more light than the HID they replace.
This is for the high beam unit which might go on the helmet. A much quicker build. The 1" Mueller pipe cap was cut using a hacksaw and Dremel cut-off disc to cut the two legs off for the mount clearance. Legs made by cuts were bent out at front to close the gap to body and bent in to make a cone at the back. Some deburring remains to be done.
The retaining ring is made from a 1" Mueller Streamline 1" copper pipe clamp. Bent over a 1" dowel, the ends filed until it would just slide into the housing. The aft side will get a beveled edge to mate better with the rounded shoulder of the pipe cap.
Shortening the cap to a minimal 1/2" for body-heat sink thermal path and moving it full back, could get an inch of depth for a reflector, best if it could also be a heat path. Advantage over mounting inside a cap is that the bottom of the cap cap be polished and is easier to access for fat fingers in assembling the LED(s) to the sink.
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