New Convoy C8 – Clearly better

[quote=ToyKeeper]

Thank you for that explanation!

OK, the more I think about it, the more I am willing to just use my Ti3 for the moonlight. Pretty happy over all with your driver. THANK YOU. At 0.1%, as long as I am careful it doesn’t blow my night vision. It is truly a usable amount of light that can go for hundreds of hours on a single battery. This is a huge improvement over my other C8s. Good to know about the other drivers as well and perhaps one day I may indeed add to my collection that I say I’m going to stop adding to;-)

Wade

The triple channel driver that Pilotdog68 worked up and Texas Ace is implementing is one of the most efficient of our modern FET style direct drive Turbo drivers. It using 3 channels, first with only one 350mA 7135 chip for moon and maybe the second level, then a second channel that has from 6 to 8 of the 7135 chips for regulated current to the middle modes up through high, and third the MOSFET that drives Turbo more or less direct from the cell. This clever arrangement makes the most of a cell and is particularly useful for small cell lights that push the envelope on the high end, like with the new XP-L2 emitters where 2000 plus lumens is possible. The C8 fares well here, as does the X6, both of which I’ve seen over 2000 lumens from a single 3V emitter.

With the reversing function one need never hit the cell with the Turbo BAM!, it’s easy to stay in the lower modes and conserve battery life until life demands the utmost delivery…

I want to make sure that I’m understanding the math correctly.

1000 Lumens -> cube-root is 10
500 Lumens -> cube-root is 7.94
100 Lumens -> cube-root is 4.64

Based on this, 1000 Lumens is perceived as roughly 25% brighter than 500 Lumens, correct? And 1000 Lumens is a little more than double the brightness of 100 Lumens?

The cube-root units are totally arbitrary. You can think of them as “steps” of perceived brightness. So, 500 lm looks about 3 “steps” brighter than 100 lm, and 1000 lm looks about 2 “steps” brighter than 500 lm. Here’s an example with nice round numbers from my ramp calculator:

./level_calc.py 1 10 7135 1 1 1000
1: visually 1.00 (1.00 lm): 1.00/255
2: visually 2.00 (8.00 lm): 2.78/255
3: visually 3.00 (27.00 lm): 7.61/255
4: visually 4.00 (64.00 lm): 17.02/255
5: visually 5.00 (125.00 lm): 32.53/255
6: visually 6.00 (216.00 lm): 55.66/255
7: visually 7.00 (343.00 lm): 87.95/255
8: visually 8.00 (512.00 lm): 130.92/255
9: visually 9.00 (729.00 lm): 186.10/255
10: visually 10.00 (1000.00 lm): 255.00/255
PWM1 values: 1,3,8,17,33,56,88,131,186,255

I find that a useful mode spacing should have roughly the same number of steps between each level, and that an interval of ~2 steps looks pretty good. So, on a light which goes up to 1000 lumens, I’d normally do about 6 or 7 steps instead: (this example is something like a “moonlight special” driver)

./level_calc.py 2 6 7135 2 0.2 140 7135 2 2 860  
1: visually 0.58 (0.20 lm): 2.00/255, 0.00/255
2: visually 2.47 (15.03 lm): 28.84/255, 0.00/255
3: visually 4.35 (82.36 lm): 150.69/255, 0.00/255
4: visually 6.23 (242.26 lm): 255.00/255, 31.56/255
5: visually 8.12 (534.79 lm): 255.00/255, 117.82/255
6: visually 10.00 (1000.00 lm): 255.00/255, 255.00/255
PWM1 values: 2,29,151,255,255,255
PWM2 values: 0,0,0,32,118,255

OTOH, for a light which does smooth ramping, like the BLF Q8, I find that it looks better to have only ~0.1 or ~0.2 steps between levels… and a lot of levels. IIRC, it has a ramp 128 levels long.

./level_calc.py 2 128 7135 2 0.2 140 FET 2 10 4000
1: visually 0.58 (0.20 lm): 2.00/255, 0.00/255
2: visually 0.71 (0.35 lm): 2.27/255, 0.00/255
3: visually 0.83 (0.56 lm): 2.66/255, 0.00/255
...
126: visually 15.63 (3820.73 lm): 255.00/255, 243.22/255
127: visually 15.75 (3909.68 lm): 255.00/255, 249.06/255
128: visually 15.87 (4000.00 lm): 0.00/255, 255.00/255

It may seem weird that low levels have only 0.15 lm between while high levels have 90 lm between, but it looks linear in practice.

I’m getting old enough that my long multi-paragraph answers annoy even me.

Just go do things, use the light that makes it fun to do what you’re doing. KISS

I was gonna +1 that post Dale, but regretfully didn't . All good!

Thanks for the detailed reply. This makes sense to me.

Oh you.

Me, I would never write anything so wordy. Don’t scroll up to see my comment a few posts ago.

Simple is good though. Like Narsil. It’s so easy and simple that it’s almost boring. It just does what I want, by default, without me having to mess with anything. I almost want to throw in some inconvenient quirks just to make it exciting again.

You can fit me into Narsil?

<—- 215 lb bag of inconvenient quirks

If every Narsil came with a free Dale, even China wouldn’t be able to produce them fast enough.

anyone can help with that new “biscotti” driver ,want to disable the memory,tabed fast 10 times ,waiting for the second buzz and full click the switch ,nothing happens.

Once in configuration mode there are essentially two choices, click the first blink or click the second blink. If you click the second blink then turn it off during the “buzz” you will have toggled memory on/off depending on where it is at the time you do this.

Thank you ToyKeeper, very nice of you to say.

lol i figured whats the problem.
i have a switch with led (without bleeder resistor)and its next mode memory ,replace the switch with normal and its fine.

Yeah, I’m guessing you haven’t added a bleeder to the driver? That’ll help the driver operate properly with the illuminated tailcap.

Preventing the driver from ever losing power tends to interfere with measurements that depend on the driver losing power. :slight_smile:

So when new version of Biscotti will be available, will we be able to safely distinguish new version of C8 clears that contains new(fixed) version? Is it clear now that it will contain V2 mark in product title or somewhere in description maybe?

I am asking because I want to buy this as soon as possible from GearBest (because coupons) like I have said but I want newer version.

Anybody know if Gearbest has updated version now?

I’d just buy it straight from Convoy.

Gearbest is cheaper and therefore better for me.
$1 is like $4 for me :confused: