WTS Lux-Pro 2D MT-G2/etc 8xAA HIGH-current e-switch conversion kits - now with (opt) driver assembly

LUX PRO MAX 2DLXII / LP1100BL conversion kit for advanced / stubborn modders.

Difficulty: Medium
Time Commitment: HIGH
Maximum foolishness of build: HIGH

dchomak’s teardown thread for the stock light: https://budgetlightforum.com/t/-/30307

$35 shipped in the USA.

This starter kit contains some parts you may find useful in your high current:

  • 6x, 7x, or 8x AA powered MT-G2 conversion
  • 2x 18650 / 2x 26650 powered MT-G2 conversion
  • 8x AA powered XM-L2 conversion
  • or whatever you think you can get away with

The parts included will help you to construct:

  • 8xAA 8s1p (series) battery carrier which may be used with spacers, jumper wires, or dummy cells to for 6x/7x operation OR 8xAA 4s2p battery carrier (for use with XM and XP series emitters)
  • Contact plate for battery carrier: Optional, strongly recommended, allows for eliminating the tailspring.
  • 20mm A20DD-LDO: a high current e-switch DD driver intended specifically to replace the Zener mod in e-switch applications and not run your cells down when they are stored in the light. Still experimental but seems fine.
  • 20mm A20DD-LDO LUX PRO edition: Like the regular version above, including the fact that it’s intended for e-switch operation, but specifically modified to allow for all wiring to come out the back of the driver for installation in a LUX PRO 2D pill!
  • 20mm A20-LDQX LUX PRO edition: Experimental linear driver. This seems to be working fine now (post # 51). We have yet to identify a proper FET for this driver, so you must sacrifice 1/3 of a SupFire M6 driver to get an FET from that which must be installed in the manner of the Nanjg-092 mod. This driver has also been modified for installation with an e-switch in the LUX PRO 2D. [In many cases] the FET must be thermally attached to the pill using at least a thermal pad.
  • 20mm A20DD-SO8 driver: a high current DD driver for use in clicky setups. Zener mod friendly, not ideal for e-switch setups.
  • Two E-switch conversion PCBs for the LUX PRO 2D. You may use one for an AA conversion and the other for a 2s1p Li-Ion conversion. (You’ll have to DIY a contact plate for one.)

Important Notes:

  • For the absolute best, most beautiful PCB edges you should cut apart the PCBs with a saw, then file off the tabs. You could damage a via on the edge otherwise. It’s aesthetic damage, nothing to worry about besides beauty. I did not bother.
  • You’ll need to do lots of filing: the battery carrier PCBs all must be filed for fitment, so must the contact PCB and the tabs on the drivers and switch PCBs must be filed.
  • Bypassing all springs is required for high current. Otherwise you’ll just start melting springs off. For the most part I bypassed both the vias and the springs on my carrier build.
  • Big AA cells will not fit in the tube! I used regular Duraloops, Duraloop Ion-Core WILL NOT FIT. Period. Well, they may fit in the 6xAA configuration but who cares about that??
  • 11+ Amps is dumb. So is 8+ Amps in this form factor. Melt stuff at your own risk.
  • This mod requires lots of work. I’ll provide no more than my usual amount of tech support, and I sure won’t build it for you! Anyone who wants to build these for others, feel free to post up in this thread. If you can’t do it please just ask your favorite driver builder / modder about it. EDIT: but I’ll assemble a driver for you :wink: - See post #16.

This base kit does not include:

  • springs
  • wires
  • discrete electronic components such as capacitors, resistors, diodes, MOSFETs, MCU, etc
  • button spacer
  • etc - please see pictures

PCB, top and bottom:

Required spacers for 53mm, 55mm, and 57mm cell spacing w/ screws & nuts:

A few more spacer related bits will be included for fine tuning. I recommend not attempting to delete the middle PCB (so you don’t have to bother with those spring bypasses…), but it is possible to do that with the provided hardware if you really want to / insist. You bring the springs.


I had to crank my camera flash way up and my aperture way down in order to get past the MT-G2 under my little diffuser. 11.4A is totally unsustainable! But you can do 9-11A on freshly charged (even rested) cells in very short bursts. 8A is way more realistic.

Every spring is bypassed w/ 24AWG. Almost all vias are also bypassed.


2x vias for BAT+ (one is LED+), 1x via for BAT~~, and 1x via for SW+. LED~~ solders on the top of the driver. Same features on A20DD-SO8 LUX PRO edition (but it also has a via for LED- if you want to use it).

This is the trickiest part of the build. You build the plastic switch assembly first with SW+ and SW-, but SW+ comes out toward the contact plate. You have to hook up everything in a small area of the contact plate and then press fit the plate. The plate will be difficult to remove. Do NOT use too tight of a press fit. A mild fit is fine.

Building your head assembly:

  1. Build the driver with BAT, BAT-, and SW wires.
  2. Build the e-switch assembly:
    a. Replace the stock clicky with an e-switch board.
    b. Bring SW- towards the front of the light, then down towards the batteries and out the hole.
    c. Bring SW+ toward the back of the light.
    d. You may want to trim some plastic from inside the plastic switch carrier, look forward some steps and do test fits to find out.
  3. Install the LED, driver, etc into the pill.
  4. Install your switch boot and e-switch spacer.
  5. Install the switch assembly by threading all 3 wires together through the holes down to the the contact board area.
  6. Solder together and heatshrink the SW+ wire, tuck it back into the hole.
  7. Solder SW- and BAT- and BAT+ wires to the contact board.
  8. Press fit the contact board.
  9. Done assembling the head.

Very awesome concept and super cool looking kit there wight. What a great way to build a high power light for a non-flashaholic.

Very nice kit wight. All the best for the sale. For what you are offering this sounds real cheap. I seem to remember the shapes from somewhere. Now only if I could remember where.

Awesome Kit! Excellent price. Good luck with the sale.

EDIT: I forgot in the giggles - Well done man! I don't think I ever saw such a elaborate kit sold anywhere on the various forums before. Marvellous opportunity for those stateside with acces to the host.

I haven’t come across this light before, but damn that PCB panel looks awesome! Might just have to get one to hang it on the wall or something, can it be scaled up to poster size? :wink:

Thanks folks! I’m pretty happy with the panel turned out.

  • I tried 7x pretty well rested Duraloops last night. I used 7x from the 8x set I’d used to do the 11.4A picture earlier in the evening. (I think that after doing several of those >11A blips and then resting for a few hours they were down to the 9-10A range with 8x.) With 7x current started higher and settled on a very solid looking 7A. IMO 7A is sane for a brief turbo, intermittent or brief strobes, etc. (7A Should be something like 49W to the LED, plus another 3-6W lost in the wiring, springs, and traces.)
  • These parts can also be adapted to work with older D-cell Maglites (the ones with no “D” in the serial number). The carrier itself should fit with no filing, same with the contact board. The caveats are as follows:
    a. The e-switch conversion requires slightly more work.
    b. The stock spring used back then is definitely too big to contact the rear contact pad. (The modern springs might be OK?) This is not a problem for e-switch use, only clicky use. If you insist on a clicky build you’ll have to install something to fix the contact issue. I’d recommend a straight section of 12AWG solid copper wire laid diagonally across the contact area and soldered into place. I haven’t measured, but I think that’s enough. Remember that (for 8s1p) you also need an airwire from the central contact provided at the top of the carrier back down to the contact plate at the bottom.
    c. You’ll need to glue or screw the contact board in place, a press-fit will not work here. That’s no problem IMO and should allow for either bottom or top loading the switch assembly, depending on what direction you go with the rest of the build.

I plan to do some more work on the QX7136 driver over the holiday. I plan to take a closer look at how the PWM is affecting the IC’s DRV output and how that DRV output is affecting the FETs we’d like to use. I’m slightly hopeful that adjusting the PWM freq may do something agreeable.

What’s currently available:

  • 10x PCB + spacer kits

PM me if you need components, depending on what you intend to build I can provide all necessary driver components along with the kit.

Looks like the linear driver is up and running. See posts starting w/ #51 over here: [retired] [WIP] 20mm single sided & 17mm double-sided ?-amp linear driver - surprisingly good!

I did some figuring. There is a lot to account for when estimating how much power will be dissipated by the FET. Under lighter loads the battery voltage will not sag as badly and resistances in the light will not result in such large voltage drops. Going from 7A to 3A may recover 0.5v in resistive losses alone. Then you’ve got another 0.1v per cell from the reduced sag.

I did some crappy math, really it was not good: I didn’t write anything down and I did not do exactly what I intended…

  • 7s1p settles on around 7A DD. Dropping that down to 3A should result in around 1.8v (0.7 from Vf, 0.7 from reduced battery sag, and 0.4 from reduced resistive losses) for the FET to burn off. At 3A that’s 5.4W, which I think is fine as long as a TIM cube or potting is used.
  • 8s1p really has the cells taking a beating in DD. When we regulate to 3A though, it’s the FET that takes a beating, dissipating ~9-10W with fresh cells. The LED is getting ~19W at that point, so you’re running at a pretty low efficiency. Once you get down to 1A you’re only dissipating 4-5W in the FET… but for ~6W output, so the efficiency figures still look very bad with fresh cells. With depleted cells things look much more rosy of course.

Generally speaking 7xAA is the most powerful configuration most folks should go with. Depending on how well you minimize resistive losses in the carrier & etc you should be able to keep a regulated 5A or 6A throughout most of the discharge.

EDIT: It’s worth noting that these efficiency figures are not entirely specific to this driver. Linear drivers which achieve more or less constant current without much PWM will be affected. 7135’s should not be expected to behave any better I think.

Me being lazy, is there a link or a shopping basket for the parts required to build the drivers?

That shape, deja vu?.....no, it must be imprinted in my brain by aliens.

Great kit, wight!

Its amazing what items are developed from crop patterns made by alien wights.

Shipping overseas in particular to Australia for the kit cost? No hurry in answering any of my queries. It is xmas after all.

:wink: Thanks djozz!

For the A20DD-SO8 there are existing carts:

For the other three, not exactly. It’s mostly well known stuff though, so no worries:

I’ll have to work on updated carts for these drivers. For now if you have questions about what’s required for a specific one of those drivers I should be able to answer.

As to shipping for the kit, I think it might not be that bad. Probably about $7 extra for USPS First-Class Package International Service. If you need/want a host I think that’s likely to push the shipping up some more.

I’m offering building & flashing services on a limited basis for $20 per driver. I’ll provide the components, reflow them to the driver, compile the firmware of your choice, and flash it to the driver. I think it’s much cheaper and better to do these things yourself, but this is a big project and I realize that some folks are better with the larger physical parts of the build than the smallest soldering.

Bump. It’s easy to build a practical light with this kit, even if it’s tempting to build an 11A peak monster.

This is so neat! I just stumbled here from the 3 MTG2 thread. That battery carrier and all the other boards are amazing! I have to apologize as I am not a huge fan of the host. But this concept could work for a number of different hosts. Do three 18650 cells or three 18500 cells occupy the same diameter/ space as a D-cell?

Thanks for the offer wight. Shipping on the components for the driver to Australia was over $25.00.

So to build the drivers and flash hardware is $25.00.

Kit price for all components including shipping to the US is $35.00.

What would shipping to Australia be? Would it be cheaper without the metal separators for the battery holder? Thanks.