【convoy】SFT40 5000K back in stock (sufficient)

4*18650 battery pipes from different manufacturers are about the same size. Perhaps the buyer will need to grind in place. The idea of such an adapter is beautiful in itself, you definitely have the talent of an engineer.

But i’m not sure whether you can use it on other lights, the springs might be too short.

Theres more


I don’t think I will sell it separately, but if you need, I can send one to you for free.

Hi Simon,
can we expect M21C with XHP50 2.0?

SST40 driver with biscotti is in design ,friend

M21C with XHP70.2 will be available soon

Will the Biscotti SST40 driver step down on overheat?

Next mode memory? Wouldn't a current/last used mode memory be muuuuuch more preferable? As far as I understand, that is.

The diagram is wrong, it’s off-time memory.

As far as I now and/or think, off-time memory means whatever mode is memorized once the flashlight has been off for a given amount of time, maybe 2 - 3 seconds. But what whatever mode? I think you're trying to tell it's the last used mode, isn't it?

When the next mode is the one memorized we just call it next mode memory.


  • Next mode memory:
    On start
    current_mode = stored_mode
    stored_mode = current_mode + 1
  • On time memory:
    On start
    current_mode = stored_mode
    stored_mode = current_mode + 1
    After x seconds:
    stored_mode = current_mode
  • Off time memory:
    On start
    if too_much_time_elapsed
    current_mode = stored_mode
    current_mode = stored_mode + 1
    stored_mode = current_mode
  • No memory:
    On start
    if too_much_time_elapsed
    current_mode = first_mode
    current_mode = stored_mode + 1
    stored_mode = current_mode

too_much_time_elapsed is when enough time had elapsed to discharge a capacitor or erase/corrupt a known pattern in unpowered ram, depending on the driver having a capacitor or not.

Cheap flashlights have next mode memory because they don’t want to spend a few extra cents in a capacitor+resistor and the memory trick is unknown to them or the time is too short (i.e. unlike the attiny13 they only have DRAM, not SRAM) in their drivers to be useful.

yes, it keeps the tempareture control function

Very nice. I would have been happy if the current 6A SST-40 driver was simply made without memory (I have never understood memory, mode memory makes a flashlight unreliable :neutral_face: ) but a biscotti interface is a nice extra :slight_smile:

Someone told me somewhere around here that temperature control was too aggressively implemented in SST40 drivers, causing step down very quickly. I myself grabbed a couple drivers to repair a couple builds for family and a friend but haven't done tests. What do you believe?

It totally depends on the host.
For instance, in a S2+ /S21 it might be useful, but on a L21A however, it doesn’t make any sense

I got rid of it by removing the NTC, instructions can be found here.

I have a question regarding LVP on the latest Convoy flashlights (S11, S12, M3, S21A, M21A, L21A, M21B, M21C, M26C). Is there a real LVP or only warning?

echikongen, concerning flashlights with unregulated MOSFET or linear drivers there is no need to worry. A standard blue crystal pump white led imposes a hard limit concerning the absolute minimum voltage which makes it work, this is ≈2.5 V (red emitters are another story). This means it is nearly impossible to over-discharge a li-ion cell with a standard white led as load. This has been tested by myself, feeding a white led with a li-ion cell directly with bare wires. With a driver in between, the over-discharge possibility is even lower.

If you want to really know, test it by yourself by leaving whatever flashlight with MOSFET or linear driver turned on for a few days. After the elapsed time, unload the battery, let it rest a few minutes and measure its no-load voltage with a multimeter. It will hardly be any lower than 2.5 V, if even close.

Concerning flashlights with boost or buck drivers powered with more cells than emitter stages (i.e. a buck driver fed with 2 cells powering a 1S emitter like an XP-L, buck driver fed with 3 cells powering a 2S emitter like an XHP50B, etc.), some sort of low voltage protection or shutdown is a must. In all these cases it usually is implemented unless it is a shoddy driver which Convoy wouldn't use.

So this is the new complaint after “I want a useless moon mode!” ?
I think memory is quite handy, and i bet many more people do too.
My complaint though, is the mode spacing of your drivers, Simon.
I ordered some anyway, but there are low and medium modes missing, big jumps from low to medium, probably because loud voices beg for moon mode…
As if they don’t own any smaller output flashlights already…

Maybe don’t forget most of your buyers (probably) want 4 well spaced usable modes, like 3 - 10 - 30 - 100%
3 modes is enough for up to 1000 Lumen lights.

3% is much too high of a low for camping/backpacking use, which is one demographic target of generic flashlights. It sounds like you need a specialized driver for urban use, but that’s not necessarily the best default driver to sell in their online store.