6. Batch "TA" 1S or 2S Bistro HD OTSM/NarsilM drivers 15-47.5mm size fit, S2+, C8, H03, MF01, MT03, Q8 Clicky or E-switch

Does this mean that boost drivers with Bistro will be available soon?

Any update on the boost drivers?

Lexel, what is “rainbow rgbw” in line 37 of your table?

Lighted tail switch.
Bottom of post 3.

Thank you!

I’m looking at the Q8 driver (4p) for a blackshadow terminator. The stock driver is 47.5mm diameter. It appears it will work, has anyone tried this?
The BST has a lighted e-switch (4 wires) would this be compatible?

Is there room to drill a small hole in the center of the board for the mounting screw? Like this:

(Photo from this BST driver upgrade thread, the SRK driver’s diameter was a bit too small)

Technically you can drill in the middle no parts or lanes there, but you have to remove the copper on both sides to prevent shorts from battery+ to ground

Hey, Tom E showed back up on the forum. Have you tried contacting him?

He is not responding on my PMs for weeks, even a friend wrote Tom begging to help


Thanks, assuming the green area has no copper… the mounting post under driver is 5mm and the nut (battery side) is 6mm, so the need to remove copper depends on how big is the area with “Q8” lettering in the center?

It will be much easier mounting to drill the center (if possible), but it may also be possible for me to use the 2 existing holes instead if I drill/tap two new holes underneath and find long enough screws, what is the diameter of the existing 2 holes?

Also, how thick is the board? And is the battery + contact ring thicker and stand out from the board? The BST stock board is 2.25mm thick and the batt + ring stands out another 1.75mm for about 4mm total height from the mounting lip to the + contact of the cells.

I assume this is compatible with a lighted e-switch? My switch has 4 wires, so I guess 2 are for the LEDs

Yes, but the Q8 driver only controls a single switch led circuit. It can’t do two independent colors.

Typically 4 wire switches can be a single common wire (common ground or common positive), one wire for the switch and the other 2 wires control 2 different color switch leds. Polarity on the switch wires is important to make the switch leds work.

the whole middle area on both sides has positive battery + copper, insulating it is nessesary or remove copper
batt+ can be used with a resistor for one LEd color permanent lit the other MCU controlled

driver is 1,6mm thick and has no stock brass ring, you need to solder it from one to the other driver with hot air
the thickness can be increased using 3 spots on the ground ring with solder blobs, or some other material like a copper wire in between head and driver

Thanks, sorry a few more questions then…

  • What are the existing mounting holes screw size, m3 ?
  • Would my + contact ring fit properly? it measures 34.66 OD and 14.90 ID, is that close enough to work on this driver?
  • Does the switch led with this driver work the same as a stock Q8? (which if I’m correct is also always on with batt pwr and blinks at low voltage)

My light has 2 color switch leds, green always on with battery power, red for low voltage warning. So I guess I could just use the green led only and it would work the same as Q8.

Also I’ve never de-soldered/reflowed a brass + ring, it’s pretty thick so I guess you’d have to get it pretty hot, wouldn’t the heat cause other components to de-solder?

For brass ring I use hot air the other side components dont fall off I have done double sided drivers a few hundred never had problems with other side components

You can light one LED with MCU the other permanent

I would imagine the non-conductive substrate of the printed circuit board (maybe made of silicone) is not a very good conductor of heat. So you can heat up one side pretty good and the heat will not transfer to the other side very well.

Beamo, you could do any number of things with a switch LEDs. It just depends on what you want. You could change the colors and have both of them work off of the MCU in tandem or you could have them both runoff constant power. I like connecting them directly to the battery (through a resistor) so that I know if the main power is connected or not. When you use the MCU output there are instances where the switch light might turn off and you might thank that you mechanically locked out the light when you really didn’t. It’s all up to you as far as what you want to do.

Ok thanks for the info.

In tandem I’d have to change the colors because one is (green) the other (red) so I think I would have brown light! (because both will be lit together unless locked out)

I’ll probably just connect the green to constant power, I think on the Q8 the main leds flash at low voltage (If Lexels driver works the same)

Lexel, will my + contact ring fit the driver? (my ring measures 34.66 OD and 14.90 ID)


Thanks, does the MCU work the leds in the same way as the stock Q8?

I think the stock Q8 switch lights permanent (unless locked out) and flashes at low voltage. (And low voltage also flashes the main LEDs)

No, your thinking of pigmented or additive colors, like paint. Mix blue, red and green paint and you get brown.

With light, it is different. Blue red and green make white! Lol

See my my avatar that is blue and pink? Those are 2 different color leds. If you kept the green and red it would just look like green on one side and red on the other.

It is cheap to order new leds in a variety pack of colors. Then you can do both leds (looks better) in your own custom pattern! :+1:

Just like with the Q8, the switch light functions the same and has programming options. You can program the mcu to make it stay off. Or you can have it on, but under certain circumstances you can turn the light off and the switch light will stay off. It can be a little confusing. If you program it to be on, then you can also set it to blink the battery level on the switch led only. At least on the latest version of NarsilM v1.2 or 1.3.

I don’t know if the switch light blinks at the same time as the main LED blinks for low-voltage. I’ve never had that situation.

Haha, yeah I was thinking mixing paint. :person_facepalming: I should have known better, thanks for setting me straight and the info.

I’m assuming it will come with the latest version NarsilM 1.3?

I’m real excited about this driver, all I need now is to find out about fitment of my + contact ring, it looks of it should fit, I’m assuming the orange part in the drawing is bare copper, and that looks like most of the bottom side.