Convoy L6... XHP70 Beast!

I took beamshots and video last night, but my internet won’t allow me to do anything with em.

What would happen if you just removed the resistors and bridged the connection with solder? Also, when your internet starts working right, can you post a pic of how you stacked the resistors. My light will be in today so I’m going to try the resistor mod too.

I simply removed a R140 from one of the LuckySun D80 drivers and laid it on top of the 2 side by side R082 sense resistors. I was only planning on using one so I stacked it right in the middle, pyramid style. Not much to see, every kid has stacked dominoes or lego’s right?

Or like bricks in the wall :+1:

Here’s a better picture of the 6/12V XHP70 sinkpad board that shows the traces. Looking at the layout of this board, I don’t see the thermal pad being in the circuit at all… am I missing something?

Thank you for that. I’ve probably seen that before myself and probably took a macro image to get there, might have even sanded off masking to reveal it, but danged if I hadn’t completely forgotten how it worked!

I had one short on me recently and so I assumed, based on the datasheet that shows the thermal pad connecting those two dies in series, that the thermal pad on the star was also doing the same. My mistake, Sorry about that!

Kawiboy is trying to explain to me that it does indeed work, even flat down on a brass pill, and it was boggling my mind trying to figure it out based on the datasheet. Looking closer clears it right up. A maze of tiny traces. DUH!

:blush:

I had the same problem when I first got to building lights. I built the driver, reflowed the LED to mcpcb, wired it all up, wouldn’t change modes?? Spent a couple HOURS messing around tore the driver out, tore it down, changed the FET, changed the MCU, tried another New Driver, same thing? Finally looked at the emitter (10X glass) sitting up a little on one end? Rang it out with my DMM, sure enough grounded to the base, F&*K!! :person_facepalming: A simple tiny microscopic sliver of solder jumped the isolation trace, from (-) LED contact to DTP pad? Reflowed , checked with a battery jump, fired up, checked it with the DMM to the mcbpcb base (no continuity) wired it up, good to go!! A year and a half later, same thing, (I forgot about it), and started the same debug process again going nuts for a couple hours, and then it dawned on me, F&*K! :person_facepalming: . :person_facepalming: , :person_facepalming: ……… :smiley:

If you would have stacked a R082 instead of a R140, would it have given you more output?

Well, yes of course. But I had a R140 and I didn’t have a R082….

Edit: parallel resistor calculator , open it, scroll down a bit to see a 10 resistor pad. You have to clear it each time and re-enter values for accurate results.

There are formula’s for converting that resistance value to amperage, using the cells output power and the driver efficiency with the emitter Vf and all that, but I could never in a million years remember all the variables.

Thanks a lot, can’t wait to get home and play now!!

I’ll say this, reason needs be applied.
If you remove the sense resistors and bridge the pads, sure, it’ll make bonkers light output, like nearly 6000 lumens. BUT, it’ll fall super fast, like to the tune of 400-500 lumens the first 30 seconds. So the gains are fleeting, lost to heat and in the long run there will be damage done shortening the life of the emitter and at a very minimum yielding very short run times from your devoutly sought after cells.
Some compromise will bring a balance that can be lived with. The stock resistance is .041. I chose .031 and the resulting 6.36A from Basen cells works for me, as does the 4609 lumens. It doesn’t get burning hot super fast, the cells are still, kinda, in their range, and all is well. You could probably go to .025 and get over 7A and it wouldn’t be so horrible, but 9A or more is really not the best yield here, which is of course completely up to you.

I don’t really understand all the resistor stuff but making a few changes there seems like the key. The driver originally had a R100 and a R082. After I talked over with KawiBoy he suggested going to either two R050 or for a little tamer version two R082 resistors. Simons driver guys are still being a little cautious but steadily improving. I can tell you for certain that this driver would have been putting out significantly less without his input. Thanks to Dale and KawiBoy1428 assisting me in the technical side of my advisory role, the L6 is better than it would have been and came out sooner that it would have. Cheers boys! :beer:

maybe DB custom can make us a video walk through just in case some feel comfortable doing what he did to up the lumens a bit? what do you think DB?

I think you guys have done a marvelous job of optimizing:

  • output
  • run times
  • heat build-up
  • form factor (size, battery configuration)
  • style
  • UI (switches and modes)
  • beam (profile and tint)
  • quality construction
  • practicality (all of the above relative to cost)

Kudos to all! :beer: :beer: :beer:

I went home during lunch and swapped the emitter to a P2 1C and stacked a R050 resistor on top of the R082s. It seemed to be a bit brighter afterwards. I have a crappy meter so current measurements won’t do me any good.

dj, is that a big drop of solder paste on leg 2 of the 8 leg component directly above the sense resistors? Need to clear that out.

If you changed to a 2 bin higher emitter AND increased the output that significantly, it should be very noticeably brighter, wide margin!

As in, just how low are your cells?

From .041 ohms resistance to 0.022527, almost half, it should be up over 7A instead of 4.8, marked increase.

I just noticed that myself, I didn’t use solder paste…it looks like the thermal paste that was under the stock mcpcb. I’ll have to take her back apart and clean it.

I definitely notice the increase in output…eventually there’ll have to be a fet+1 installed.

Still waiting for my L6 here in Germany….