Alright, as promised, here are some photos. Before my shift I finished all the soldering and assembly necessary to slide the battery pack and "can" into the body of the light. I have talked about the construction of the USL before in my
Battery construction details & History of the USL thread, and you can feel free to check out the link, but the short version of it is this: the design minimizes resistance throughout by using a single welded pack with low resistance joints, a low resistance electronic grade rocker switch, and by directly soldering all other connections except for the ceramic socket which is held by the can, and into which the lamp leads are pushed. These connections are the only ones that are not very low resistance, but that can't be avoided of course.
Thus, the strengths of the USL are also its weaknesses: because the pack is a single welded pack, if one cell goes bad, the whole pack must be replaced. And because all wire leads are as short as possible, and because the internals are squeezed into a 2D mag lite, the battery pack is not easily replaceable. Ginseng's Aurora and Aurora2 lights have a removeable pack, and AWR's Mag100R has not just a removeable pack, but a "pack" that is in fact a battery holder. There are definitely advantages to these designs. But there are also disadvantages.
Anyway, here is a picture of a USL pack right after I soldered on the ceramic socket lead from the can:
That's the negative contact to which the can lead was soldered. Below and to the right is the positive contact. That white wire lead which is sticking up in the air to the right of the can is the lead which was soldered onto that positive contact.
A side view will make things more clear:
As you can see, the two white leads will be cut to the proper length and then soldered onto the switch leads. So there it is! The heart of the USL. A lower resistance circuit path light you will not find.
That black thing sticking out the back of the pack is the charging connector--what I was calling the "pigtail" earlier. Those wires are also soldered onto the + and - contacts of the battery pack.
Anyway, when I get home tonight I will install the internals into the light bodies and solder the leads wires to the switches, and RTV the packs in place, and let them all dry overnight so that they can be mailed out tomorrow.
Here is a picture of the one completed blue USL (top), a 2nd blue one which has the internals installed but with the switch not soldered to the leads, and three sets of internals which I will install into lights when I get home tonight.
So, that's the update!