Convoy 3x21A SFT-40 6500K first impressions, info, mods

I have 3x21A Sft40 and 4x18A Sbt90. I bypassed springs and sanded down the middles from flattop adapter. Negative end pcb contacts to the flashlight body only with small steel screws. Three in 3x21a, four in in 4x18a.I added three more bigger screws to 3x21a to accomondate that. Still the 4x18a outperforms 3x21a clearly and tint is nicer. I use bundled Liitokala batteries on both.

For those who might be interested I have few comparisons. Be warned, I’m not a photographer.
Left side 4x18A, right side 3x21A

Bottom of the ramp


Top of the ramp

You are right - the 5700K SBT90.2 has a more pleasing beam tint, plus comparing a single SBT90.2 to a triple SFT-40, you don't have all the artifacts associated with 3 reflectors. Those deep reflectors show their effect in that last wall shot.

Did you notice or measure a bump with the spring bypasses?

Jumpering out the resistors should be a bigger bump, but does have risks. I'll probably try it first before piggybacking in a driver replacement. I don't have to worry about blowing out the driver circuit. I don't care for the UI in this light at all. The press&hold from OFF should still allow you to ramp. If last used is max/turbo, you'll get blasted with it if you need anything but the lowest setting. In Narsil and Anduril, we accommodate that by adding a delay at the lowest setting, then ramping up is engaged. The linear ramping drives me nuts -- I thought Simon was asked to fix this over and over, I don't get it.

Truthfully I didn’t notice anything happening after spring bypass. Might be very small increase if anything at all.

The disk quality is disappointing. I have the 4x18 and the disk is super strong.

That’s one area I wish Simon would innovate: UI. I can live with quality eccentricity, but UI’s are easy to deal with, especially since pretty much every manufacturer is using Anduril these days. Great lights let down by wonky UI’s. To be fair though, Convoy has gotten better with USB C charging and great single cell lights with e switches.

The greens in the pics really surprised me. It doesn't look that bad in real life, even on a white wall. If I put it side by side with an old SST-40 6500K, the SST-40 looks blue and this SFT-40 is more on the green side, but not the strong greens in the pics.

Looks like this light is still one i want to (try) to get, with SFT40. I agree my pictures give it an unfair green look as well, which doesnt show as bad in real life. Sad to hear about the UI, i have been reading about it on the Convoy thread too.. I don't know how i would fix something like that, so' i honestly might hold off on this light until Simon can straighten it out or until i have the pleasure of watching your piggyback mod and determining if it's something i can do. I mean sounds wroth it to buy a $23 astrolux ec01 (Anduril) and rob the driver for a piggyback? is that how it works? lol. i obviously have no idea. Thanks for the insight Tom

It's common to see our smooth ramping poorly implemented. Back in 2016/2017 during the Q8 development, the Thorfire engineers went off on their own and decided to clone our UI on a different MCU, rather than use the ATtiny85 and our firmware. The ramping in that prototype was linear as well. Thorfire ended up firing the engineers from what they told us. There's been several other smooth ramping lights with the same problems, and typically they make the ramp speed too long, longer than our 2.4 secs (16 msecs x 150). Our ramping tables are 150 entries and ramping increments/decrements every 16 msecs.

Love those ThorFire’s

!

!

!

!

Updates in the OP and post #2 for mods.

I was wrong I didn’t mean XHP50.3 but XHP50.2 3 volt. The 6500K have the worst green/yellow. 5700K a bit less green same amount of yellow. When outside not much of a factor compared to white wall shots. It’s a pretty drive such a shame a little resistor mod could do it. SFT-40 at 5.66 amps each is factory nice but not around here. 8-9 seems very possible. It does look identical to the 4x18A driver running the SBT 90.2 including the two big resistors rating. Looks like a one size runs everything.

I guess he amp limited the 90.2 version as well? I think there's something in the circuit to limit amps, not just those big resistors. Not sure what type of current sensing but all those components to the right of the big resistors look like they are doing that, but not sure.

I hope someone gets to compare sst-40 to sft, in this same light, with such good photos as OP. I have the sst40 5k on the way, but i am wondering more about beam shape than tint, just so I can understand when I should or should not choose sft.

Thanks Tom, great pics and details. I figured I could just use a convoy, but I will look it over for any issues when it arrives, thanks to your tips.

I should have taken a couple pics of the full beam pattern - there are a few artifacts. I got multi-LED SMO reflector SST-40's that look better, but the power/throw of this flat LED is probably more susceptible to the artifacts, yes - hard to tell unless you can compare them side by side. But also, dunno if they are really noticeable outdoors.

I love threads like this, Tom explains things well.

Simon makes a fantastic host, always did, just think the electronics and attention to detail lacks a bit:

  • of the stock 18 AWG wires, for some reason black was shorter than red - doesn't seem to be a logical reason for this
  • the red wire had a good slice in it, but seemed to be in a safe place - probably occurred on the tight passage/drilled hole through the shelf. Could have been bigger and smoothed out the sharp edges.
  • the wires are a type of low strand count so they are stiffer than what we typically use and the silicone coating is thinner, compared to Hank's or Turnigy branded
  • doesn't give the priority to the MCPCB contact surface -- such a critical thermal junction, must be flat, smooth, and use a quality grease (falls short here)

Granted the shelf and MCPCB requires some labor, QC, and/or better machining, I'm sure costly, but using a cheaper grade wire and thermal grease? I think the few cents extra here is worth it.

For the host, the threads, anodizing, finning, designs, optics have always been above this price range.

I totally agree with you. Convoy overall is excellent but always lacking in some way. I hope he improves so these deficiencies can be addressed. Don’t forget, he is making money, we are buying flashlights. He has a bigger stake in this than we do.

Post #2 above updated with the full mod completed.

great review, thanx

sft40 totally suck in matter of tint. it is even worse than sst70.

what is advantage of SFT40 over XHP35 HI? the last one looks way better in matter of color