What's the difference? - FX6 and LD-22s aka LD-33s drivers from KD

Flashlight Modding and DIY Parts
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Hi all,

These two drivers from KD that fit the 22mm driver space on my Jaxman x1 seem very similar to me other than the fx6 is older and this LD-22s (or LD-33s?, its labeled as both in KD's description) seems to be recently released. Links below:

FX-6 Driver

LD-22s? LD-33s? Driver

Can anyone tell the differences between them other than the UI and output levels from looking at the boards? Kd's descriptions are a crap-shoot at best, but I can only tell that the LD-22s states that it's "constant current" and the fx-6 doesn't claim that. Also, it looks like their low voltage protections might be different, and the fx-6 does not state that it has mode memory while the ld-22s does. They both appear to be two-cell only buck drivers with similar max output. Really wish they could handle 3s cells too. Why is there variation in their max current? For example, the fx-6 says its 4500ma or 5000ma, and the ld-whatever is 4800 or 5000.

I plan to swap in an xhp50.2 with the driver at the same time, but both the drivers are labeled for the older xhp70/50/mt-g2's with higher Vf. Do two cells provide enough overhead voltage for a buck driver at 5a with any of those emitters? Just trying to make some sense of these before ordering if anyone has experience with them or can tell from looking at the close-up pics.

As a side note, the stock Jaxman driver seems very high quality and puts out 3a on high already to the xhp50, but I don't know if it'll handle resistor modding for 5a or not. I can't exactly remember what resistor value I used without taking the light apart, but I think it was an r300 or r250 on top of the original r150, so I think it's putting out about 4a now. It gets warmer a little quicker, but not alarmingly so, I just don't want to toast the original driver for no reason when for under $10 5a drivers are available. I used the valuable info in this thread on post #58 from WolfA to help me with the modding: jaxman z1 discussion

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For the FX6 maximum driving current is listed as 4500mA in the table, and it happens to use an R082 and an R100 as sense resistors onboard, for ≈45.05mΩ combined resistance: this is ≈0.2V sense voltage. Unfortunately the pictures for the LD-22S are not as detailed, even on their AliExpress partner site (the “LD-33S” designation looks like an error to me; there was an LD-33 back in time, though much different).

I like the LD-29S, drives at 3A with just an R020 which means just 60mV of burden voltage, and handles 3 cells in series. You would need to sense resistor mod it for higher output, and maybe upgrade its inductor. No additional problems besides these and a 22mm daughter board as it equips a beefy 10A schottky.

Cheers :-)

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Thanks Barkuti! So, if I wanted the LD-29s to put out 5a instead of 3a, what value resistor should I add in parallel on top of the R020? That's one of the smaller sense resistors values I've heard of. I bet resistors in that low of an ohm rating are difficult to find. If the resistor were simply bridged would it still work? Have you boosted the current on these drivers before?

What value of inductor would be swapped in? I know it's probably one of the larger ones with the exposed copper wires wrapped around the ceramic (?) core, but does the rated current/resistance on the inductor matter? or just get the biggest and beefiest looking that will fit?

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Oh, I noticed the Kd description on the LD-29s says it have 5 modes including strobe and sos. That’s a huge bummer if true. Is that a mistake in the description or is there really strobe you can’t get rid of? re-flashing a driver firmware is waaaayyyy out of my league

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mountainair26, since I = V / R with 60mV of sense voltage an R100 (100mΩ) would add 0.6A, thus 3x R100 1206 (1206 is my guess for the footprint, ≈3×1.5mm) resistors would do +1.8A, for example. Those can be gotten for cheap on eBay, example: 100PCS 0.1 ohm Ω R100 100mR ±1% 1206 (3216) 1/4W SMD Chip Resistor 3.2mm×1.6mm @ zq8
Less common R056 (≈+1.071A each at 0.06V) units also available: 20pcs 0.056ohm Ω R056 56mR ±1% 1206 (3216) 1/4W SMD Chip Resistor 3.2mm×1.6mm @ 185115
If you'd like to search for other values, use the Advanced Search and restrict the search to Asia if you want it to be ;-) :-D cheeeeap: https://www.ebay.com/sch/ebayadvsearch
Yes, strobe and SOS hurrah! Otherwise, I really like the mode spacing.
Pretty sure a large and beefy inductor like the one on the FX6 would do well and help with heatsinking, I've done this myself to an old driver without issues. I once thought over this kind of LD-29S mod, and I believe it could at least handle 6+A.
Cheers
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excellent info thanks!!

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I really wish there was a way to get this driver without Strobe/Sos. That completely ruins it. Is there any kind of fix for this?