Now they can sleep in total darkness inside my camera bag that I have betrayed. 
Anyone knows is there a way to reprogram the low voltage protection through the firmware?
If it can’t be done through firmware, may I know which resistors to change and how is the calculation for resistor values?
You can adjust it in the firmware, although it can be tricky as you will need to use TK’s voltage hex file to figure out the right settings and then test it at a few voltages.
Is the voltage reading off? It is common for it to be off 0.1v, even 0.2v is not something I would worry about since there is a fair amount of margin for error on this.
Ya, one driver battery check is out by 0.2v. The LVP seems to kick on prematurely. So I thought if user can do manual offset via clicks on buttons.
Sadly no calibration is possible via the menu, only in the firmware code.
You can adjust the voltage divider resistors to correct the voltage but that is not always easy.
Although it may actually be working just fine. If you are running it in a high mode the voltage in the cells will sag lower, causing the LVP to kick in but when the load drops the voltage increases, which is why you get higher readings without the light being on.
It's something I want to add (i.e. voltage calibration), looked at it briefly, little involved but I'm getting, really really desperate to get this feature in for both voltage and temp. NarsilM uses voltage levels to the 100ths, not 10ths, so the data entry should be 2 digits - I want to make it work just like other config settings. In 100ths you can get it very accurate. In the firmware it's roughly 10 to 40 for 0.12V to 0.40V (usallly tighter from 0.20V to 0.36V or so) addition for taking the diode drop into account. I do this manually by checking batts at differing levels, again to 100ths precision.
In theory, I believe the diode I use supposed to be a ~0.24V voltage drop.
The variation from piece to piece is probably because of variances in the diodes and MCU's. I'm not really sure though if the bulk of variance if from driver design to driver design, or more from piece to piece. It's hard for me to tell because I generally reflow one driver at a time when I need it, and almost never use the same driver back to back.
To me, the ideal UI for this would be press&hold while in voltage display (blinking out) mode, the it goes into config, for data entry of 0.35V, blinks twice, then you click 3 times, stop, then it blinks twice again to confirm, then you click 5 times, and it blinks the final confirmation blinks - 4 quick ones. It should feel exactly like entry of other config settings.
Should work the same way for temperature calibration of entry of a 2 digit celsius temperature.
Tom, you might look at the Anduril code, I think TK has managed to get at least some of this implemented already. It would be cool if we could merge anduril and Narsil. They both have pros and cons and I think they could be blended together really well to get all the pros without the cons.
Yes, somewhat. Unfortunately I really don't like the turn OFF delay in Anduril - last I heard from her there's no fix for it, and not sure if she will fix it based on her response - it's not important to her, least not as important as it is to me. Actually I'm surprised no one else noticed or complained about it, or if they did, I didn't see it. It's something very basic with the most rudimentary action of the UI -- turning off the light, and it has an annoying delay... I don't get it.
If this delay is not fixed, I'm not gonna give up on NarsilM.
When I checked Anduril source code for voltage monitoring, I don't think she's using the full resolution that DEL developed and I brought into NarsilM, so she stuck with the old method with resolution in 10th's not 100's. Forgot the details, but DEL used higher resolution AtoD on the reading. He shared his code and I like it - dropped it right away into Narsil.
Fireflies is the only company using Anduril so far. I haven’t followed their lights, but it seems Anduril is well liked.
The Sofirn 21700 C8F has a little bit of a turn off delay. It bugs me a little, but not too bad. I do prefer the instant off of Narsil, though.
I haven’t tried Anduril yet, but I want to.
I certainly could make mods to Anduril myself, but with the current config/default setup, there's only like a handful of bytes in code space available, so there's not much room for doing anything.
The enhanced voltage reading I could probably handle, but will probably take more code space. The OFF delay could be a tricky one - I would not think she simply put it in there intentionally, it's probably needed to differentiate input sequences or states, so I'd suspect a fix for it can get complicated easily, and of course take more code space....
Ugh... I spent a little time, built in in Atmel Studio for Windows, but haven't installed and tested it from my own build. Everyone else seems to be using Android/Linux though it was easy for me to compile/build it on Windows .
There's a ton of things I prefer about Anduril, but the basic ON/OFF functionality right now is a major issue to me, though everyone else seems ok with it (?) I guess...
I only have 2 lights right now running it: an E07 and PL47.
She’s mentioned in the past that there’s no real way to get rid of the turn off delay.
You two should probably talk directly.
We did actually, on posts in a thread, forgot where. Dunno - she said in a post she was gonna look at it, or someday fix it, dunno - different timeframes I'm sure.
Well from what you are saying, it doesn't sound good - worse case scenario. In Narsil I always gave the 1st click priority and kept delays really tight - it can be annoying to some. Only thing I dleayed longer than TK was blinks, but I think in Anduril she slowed them down. In her earlier power switch drivers, i simply could not count the blinks - maybe it's an age thing or something, but I needed the blinks to go slower, otherwise I couldn't count after 4 or 5. My hands are still quick but maybe my brain slowed down... I'm sure I'm 25+ years older than TK 
Several people also mentioned that they wanted instant off as well when I brought it up in the firmware thread last year. She said it should be an easy change and a define could be added to allow this to be selected at compile.
She mentioned she was working on some updates and got some pushed to the repo but not sure if this was included. I agree, this is also the biggest sticking point for me as well other then the thermal control that does not prevent 100c temps.
Like I said, both have their pros and cons, I think they could be blended together to get all the pros without the cons since they are very close already. I do like the simplicity of the anduril defines and the fact it makes it easy to change the driver layout.
I think you are right about the voltage sag. This MT03 is about 15% brighter than the other one. It is the old MT03 with 6 wires between MCPCB and driver. I think it draws much more current and cause the voltage to sag more than the other MT03 TA that has only 2 wires between MCPCB and driver.
That is really good UI and easy to use. But will there be situation voltage measured too high and needs an negative offset?
Also, I wonder is there solution to include voltage sag into LVP calculation? It might be too risky though.
I’m interested:
Tint: NW (4000-5000k)
Emitter: CREE XHP70.2 P2
Iv'e done dozens of lights/drivers with NarsilM and never had to go negative - that would be wayyy off. With the fake MCU's from China, suppose anything is possible but the D1 diodes are typically dropping 0.2 to 0.3 volts going in to the MCU, worse ones from China maybe up to 0.4V.
I am not worried about the voltage sag personally, once the voltage is that low you are almost empty anyways and over-discharging the cell is the quickest and easiest way to damage them. Better safe then sorry in this case I think. I actually kind of like the voltage sag causing early step down, it warms me I am getting low on power and extends the runtime in the low modes after it steps down.
Yea, voltage sag I've seen, but mostly in 16340 lights where the battery is weak and the amps relatively high. It's real annoying when it happens though, but honestly, I don't think I see it now with the high performance cells, though I generally don't let my 18650 cells get that low.
Tom E, good to know that. Thanks.
Ya voltage sag is annoying. I think MT03 TA really needs better cells like 4*21700 for its Turbo mode.
TA, it is probably my addiction for Turbo mode and I notice I recharge my battery quite soon at about 3.7 to 3.8v for MT03 with TA driver. It could be contact issue too because I use magnets as button top, I should measure the resistance of the magnets. To squeeze more juice from the batteries so I kind of ignore LVP and put the light back to Turbo.
MT03 TA is such a fun light with so much output with such a small size. So I use it for fun only.
Is the voltage measurement on the battery or on the LED forward voltage?
Since LVP kicks in, doesn’t it mean it see about 6V? And at 6V, XHP70.2 consumes about 4A current, total 12A current for 3 LED, so it should be about 6A per 18650 cell.
I looked at Sony VTC6 discharge graph by HKJ, it is almost empty when it reach 3V with let’s say 5A discharge current. But I found that my VTC6 are all about 3.7-3.8V and it only takes about 1400mAh to fully charge them. It has still 50% of charge in them.
I wonder what will be the voltage if the the driver is measuring with two wires directly connected to batteries, I mean not sharing any path with the LEDs.
My VTC6 all measure about 15-20 m ohm by charger. They are much lower than my other Samsung 30q which is about 50m ohm.
Again, measuring 6V could be the batteries are discharging let’s say 10A and voltage sag due to that. But LED is seeing more than 6V else it won’t draw 10A from battery.
