My Convoy L6, lighted switch, TA FET driver plus mods

Looks like you are having fun with this light :partying_face:

Cool write-up for others who are modding this light. :beer:

Last night I charged up the solder blob topped LK 5000's to 4.20V and re-tested. Actually I use only one that's solder blob'ed since there's a driver spring, bypassed of course.

Amps at the tail: 17.3A, lumens: 9,210 @start, 8,160 @30 secs, and 193 kcd @5m (879 meters)

Parasitic drain is 62 uA (no indicator LED on this L6), so pretty happy with that low reading. No need to turn off the power switch.

Thanks to steel_1024 for the XHP70.2 P2 3B!

It's an impressive thrower, but way too much heat to handle, but that's what thermal or timed step downs are for.

I use Narsil v1.2 so I can have the lvp, but you can’t have that and thermal monitoring at the same time.

Maybe v1.2 has a timed stepdown?

That’s no big deal as I use my hand to monitor temperature. For normal use I adjust to slightly below turbo output. You still get bright output, but much less heat and battery load. That’s much more practical. Then as the voltage runs down I go back to full output.

I save the full output with fresh cells for testing or showing off. Lol

NarsilM has LVP and thermal step down for 2S setups. v1.2 had a poorer ramping table as well. Bunch of improvements in NarsilM.

Not sure I can afford the time to look back any more at old revisions, unfortunately.

The stock driver is a buck driver, tailcap amps are basically a useless measurement for buck and boost drivers.

Buck drivers keep a constant output current but the input current will vary with voltage. Higher input voltage = lower input amps and vice versa. So in this case the lower the amps, the better the battery.

Cool write-up Jason! When I want to mod my L6 I will find my inspiration here. The lighted switch will certainly be on the list! (and XHP70.2 and SMO reflector).

he got v1.2 with my improoved ramping table

What? I’m pretty sure the FX30 is a constant current driver.

It is a constant current buck driver. That means the output is a constant current.

The input current is anything but constant though. It will pull as little or as many amps from the battery as it needs to keep the output constant.

So if the cells sag to 8.0V it will pull 4.6A from the cells (aka, at the tailcap)

If the cells sag to 7.2V on the other hand then it will need to pull 5.1A in order to maintain the same output current.

Amps x Voltage = wattage. Wattage is a much better way of thinking about buck and boost drivers as the LED Vf doesn’t change much.

8v x 4.6a = 36.8W
7.2v x 5.1a = 36.72W

It’s funny because I’ve done a ton of amp draws on the FX30 and never noticed the amp draw at the tail increase as the batteries went down. In fact, as the batteries went down I could notice the output (both amperage and lumens) dropping. It did stay pretty bright at first, but below 3.7v or so it was noticably dimmer.

I wonder why these driver specifics were never mentioned before in any of the L6 threads?

I and others have mentioned them before many times. Even put the driver though a full test on the bench to see exactly what it did.

The output remained more or less constant from an input voltage of 8.4V down to around ~7.8V. The output them spiked a bit for some reason from 7.8-7.6V before dropping back to normal until it could not maintain regulation anymore. Somewhere in the low 7V range (which would be about 3.7v per cell). Although all of this is from memory, so don’t take those voltages as gospel.

At that point it was just a high resistance direct drive driver and output would drop as voltage dropped.

This is exactly what you would expect from a cheap buck driver and how it is supposed to work (minus the spike in output in the 7.7V range).

I’m sticking with FET drivers in the L6. :+1:

I did try the xhp50.2 with the FX30 and wire across the resistors. I didn’t have my clamp meter then, but I think the amp draw was 9 or 10 amps. I didn’t even think the FX30 could handle that much without smoking something.

Thank you for your pictures and information. Today I finally put Kaidomain driver and leds on switch :smiley:

Great work Jason! I like the lighted button. Maybe I need to buy an L6 again :smiling_imp:

I updated the throw numbers in post 8 and added some pictures to post 9.

in #6

What different between “Indicator LED” and “Power on LED”?

They are very similar, but you can’t have both low voltage protection and the indicator led on the 2 cell version of this driver.

Narsil v1.2 has LVP, but no temperature support or indicator led support.

Narsil V1.4 does not have LVP, but does have temperature support and indicator led support.

Basically the indicator is a little fancier than the power indicator. It can be programmed to stay on when the rear switch is on or you can manually turn it off. When you do a battery check the main beam as well as indicator led blink at the same time.

With my light I only needed the power indicator so that I know when the rear switch is on and off. So I chose to have the LVP and no indicator led or temperature support. I can measure the temperature with my hand. Lol

Here is what Lexel said about the indicator led.

Thanks

I plan to use NarsilM (2S) for XHP70.2.

I am not able to modify the firmware code.

Which one is better?

Which is better between what? V1.2 and v1.4 or do you mean both of them compared to M?

1.2 and 1.4 are equally good, they just have different options. Narsil M is supposed to have the ability to let you assign pin 7 so you can choose between temperature sensors or lvp. I’m not an expert in Narsil and the M version was not ready yet when I ordered my drivers.

Is Lexel making you one? If so, I would ask him which version suits your needs.

I understand “Indicator LED” and “Power on LED” now.

I can flash my own firmware.

I’m just a little confused in these versions.

So still have to study these (Narsil) information. And to enhance my English understanding.

Thank You!