Q8 modding

Oboy. Anyone ever tell you you’re fun to watch? Looking forward to this.

Oh boy, Yea, I need help understanding these 2 things - where exactly the copper rings were soldered - very interested in that. Think the copper disc simply connects all the traces together?

I'm also unclear with the driver mount issue. I would think all that matters is the connection of the battery tube to the driver - that's it. Contact of the driver to the head housing is not needed - no reason for that connection - you need a strong path of Batt- to the driver.

Least this is what I'm thinking??

Dig in, Dale!
Just to get this clear, since I don’t have my lights yet and can’t check it by myself - does the outer edge of the battery tube rest on the drivers backside or is it’s diameter larger than driver and it rests on the shelf? If the first is true I still don’t see why any ground contact to the front casing is necessary. The light should even run isolated from the front case and without screws.

If you screw the battery tube in it makes contact with the driver outer ring but after screwing it in a few times, i can see that it did not make contact on the full surface. But the tube is also connected with the head through the threads so the current will flow partially from tube direct to the driver and through the threads to the head and then to the drivers other side groundring. I thought about this too and that is the only explanation i can think of. I think reducing the contact resistance in the light will be even more important when a LED change to SST-40 or Luxeon V leds will happen (because the Amp draw will get up to ~ double what it is now).

Ok, I see your point. If the tube doesn’t make good contact to the driver this will influence current draw. In the pictures of Tom E’s prototype tests the threads of tube and head look anodized - has that been changed?

Edit:
is it possible that the head of your screws is so big that it touches the batterie tube?

Threads on mine are anodized, and a bit goopy with lubricant.

The end of the battery tube is bare metal, and feels a bit rough to the fingertip (sawed off and not polished?)

Looking at the ground ring around the outside of the driver, it has some scuff marks around about a third of the circumference. The rest is pristine shiny.
One of the scuff marks is interrupted next to the screw head, suggesting the screw pulls the ground ring a bit out of plane so it’s not rubbing right there.

Are we wearing away at the ground ring trace on the driver every time we change batteries?
How thick is that trace?

Would adding a dab of conductive lubricant around the ground ring contact protect that trace?
Or polishing the end of the battery tube a bit?

I deeply hope we haven’t found another potential design flaw, I have seen this earlier in cheap SRK clones. Bad contact between battery tube and driver board. Last time I simple beefed up the trace with solder, since I didn’t have anything better at hand that time. Worked out better than expected but of course a brass or copper ring would be far better.

Hank is onto it…. and yes, a good finish on the end of the battery tube will allow for the most contact while protecting the trace. A rough end on the tube will be an abrasive to that trace, while also providing the peaks and valleys that will undermine a solid ground contact. And that 1/3 contact, all the current flows through there so if you can get the driver to seat firmly on the head’s shelf then the battery tube should also fit squarely onto the driver contact ring and provide the optimum ground path.

That’s the biggest trick to getting the most out of a light, making all contact points optimized to cut resistance everywhere possible, or at least in my experience. I’ve even gone so far as to solder thin copper discs on top of the springs so they make a large contact to the negative end of the cell. The little things, added up, yield the biggest gains.

Designers need to keep a thorough list of all the possible bad designs that have been used in the past on any similar product.
There has probably been a financial reason for every corner that’s ever been cut — watch out for those choices to happen again.

Does anyone build driver PCBs with a solid copper ring instead of a trace around the edge of the board?

When all that’s done, stick an UCLp in place of the glass lens and measure output again. :smiley: I remember seeing a 17Kcd gain in an Maxtoch SN6x-2s by simply replacing the lens with an UCLp.

Seems the good drivers have thicker copper pours for the traces, like 3oz, or the same as the new Noctigons. If they’d wear out it’d take a lifetime of regular use I’m pretty sure.

A suggestion for those who have some conductive lubricant like Nyogel — wipe the driver board contact ring and the end of the battery tube clean of the lube that’s on them now.
I wiped off a lot of dark discoloration, presumably metal powder.

Then —
Run a thumbnail along the bare metal surface of the end of the battery tube to feel for any rough spots.

I found one little ding on that metal face, a tiny notch with a raised edge and a missing chip of anodizing just outward from that. I cleaned up that rough spot (rubbed it with a bit of hardwood til I could no longer feel the raised edge).

Figured that was likely abrading the contact ring.

Added dabs of Nyogel to the bare metal surfaces.

Figured I don’t know if the lubricant supplied on the flashlight is electrically conductive or not. Has anyone a way to check that?

When I was a kid my Dad owned a Lumber Yard. I remember the finer grades of lumber had to be slid into bins by hand… I used that manual labor time to let my mind wander and focus on issues. For me, modding lights is a hobby, a manual labor where my mind can be free and I tend to work a light as a matter of habit more than giving it deep thought, the learned things that time has shown after hundreds of mods. So, with health issues in mind, I mod for the escape with the ever elusive maximum in mind as a target goal. It’s not electrical engineering or deep science, it’s pure fun, by design, to escape the serious issues that cause me mental anguish and physical pain. In the end, it matters not one whit to me if TA or Jerommel or TomTom or whoever is actually “right” or not, I’m all about results. For the most part, the 140+ lights I’m surrounded by are the provenance to that way of thinking. (And the hole in my bank records.)

How about lightly tinning the ground contact ring near the FET? That’s where you’ll want contact first as otherwise the current has to go around the driver through a trace of unknown resistance. And a bit of relatively soft solder with good tightening of the tube should mean a good contact after a little wear. At least that’s my theory :slight_smile:

I did this with a SRK mod (but the whole trace not only a part) and it worked out ok - but it is not beautiful. And after some usage you may have to reheat the solder since it gets flattened by the tube.

I will check the wear on the outer ground contact ring in the near future more often. And if its get to much i will put solder on it or put a brass ring on it if i can make one (making it by hand without proper machinery will be a challenge)! A driver retaining ring would solve the “problem” clean and would also look good. But my “first aid approche” will be to polish the tubes contact surface to reduce the wear.

Would the wear and tear be reduced on this ground ring if the effort was made to only “snug” the battery tube instead of cranking it down tight? Just a thought…

We discussed this wear&tear on the ground ring before, when TF first introduced us to the nightmare of removing the brass retaining ring for the driver. It's barely hitting the outer edge.

I see now what you guys are talking about with the screws pulling the driver up, resulting in poor contact -- this is why I drilled out the screw holes and am using low profile button head screws now. Believe I posted pics of this earlier. The wear is still an issue - we asked TF to use a thicker layer trace there, but doesn't look like they did. Dunno bout the follow-up on this, or if it was dropped. Think DEL, Miller, or djozz could recall better than I can.

What I would like is spare driver boards, so I can update my old SRK clones. Pretty please.

Only on BLF, I may have to ship my 2, when they get here, to Texas as some of this is getting over my skill level but certainly is really interesting. Meteor mod is an amazing idea as are all of the others as well.