A Ray Bow RB 501,
a budget two zone zoomy, with advanced TIR + aspheric optics, from Taobao.com https://world.tmall.com/item/15302013715.htm?spm=a312a.7700714.0.0.JDDdGF&skuId=57727356140, via an agent. The head slides on two o-rings, and it is generally very well built for an un-shipped price of around $5 with battery. See New or little known multi-zone (Fresnel) zoom optics.
This is just a driver and LED swap, but with a lot of details. Yesterday is the first time I built a Wight FET + 1 x 7135 driver. I have been getting them from BangGood and already built from Richard, because they looked hard to assemble. This one is with a board from OSH Park and a kit from Mtn. Elect. It looks a little crooked, but it works.
I also had to file a 16 mm. Noctigon down to 8 mm. The old star was put in place with rubbery thermal compound, so I used thermal epoxy. I didn’t file the pillar of the pill shorter, so I had to add an o-ring spacer to get it to focus, even though it had travel to spare before. The Noctigon added over a mm.
That is an XP-G R5 4C. I put heat sink compound on the pill threads and the front slide o-ring, as usual.
Added: The driver started having problems soon after I wrote this. It may be my build or the narrow ground ring. I plan to try a BangGood A6 driver in it. It worked really well when it worked and was, briefly, among my best lights.
August 20:
Because the narrow ground ring may have been the problem, I switched to a Qlite 11 x 7135 driver.
A problem remained that it went out, without changing modes, when the optics touched the dome of the LED. I added a 2nd o-ring spacer and partially de-domed the XP-G with file. It works now.
Next time: BangGood driver or Nichia LED, less solder between LED and star, file the pillar flat and 1 mm. or a bit more shorter. De-dome.
It seems to be not as bright as it was with the FET driver, but it works. The file de-dome seems to have made the spot smaller.
It seems not bright enough for the current it draws. Maybe the LED is damaged. I am changing to a Nichia LED that may work better and will draw more current. The pill is only about 1 mm. thick at the top, so I can’t file it to make up for the extra thickness of the direct thermal star.