Ordered.
Would actually be the 10th as I have two copies of some of their lights!
You can have the shortest, thickest leads in the world, but there is no getting around the fact that the current shunt on a DMM adds significant resistance. On my UniT 139c I just measured the shunt resistance as ~20mOhm. That works out to a burden voltage 200mV at 10A.
That’ll make a big difference in the draw of a direct-drive light. It’ll make no difference on a regulated light (like the Convoy 8x7135 driver, as long as the cell voltage is high enough to overcome the burden voltage and the regulator drop-out voltage.
This is why people use clamp meters.
@eas, that is actually a good thing, as it makes the measuring method more reliable since the shunt’s resistance is a like a spring’s resistance.
20mOhm is about the same resistance in the S42 spring, so that is good.
I also forgot to tell you I used the 16AWG wire only as an external shunt :D, and calculated the current, which got me around 9,5A.
That makes sense.
For my part, rather than trying to approximate the spring & contact resistance, I’ve made tailboards with a (bypassed) spring and heavy gauge wire for the clamp measurement loop.
Earlier I experimented with measuring the resistive voltage drop across flashlight body tube. It worked pretty well with my precision bench DMM, but calibrating it was a pain.
Measuring the resistance using the DMM was problematic. Two-wire measurements had a lot of variability. Four-wire measurements were hard to manage in an assembled light, and also had a lot of variability. Increasing the signal-to-noise ratio with higher currents was a pain to rig up, and brought its own sources of error. It was sort of doable with FET+1 drivers because I could use the regulated modes as an internal calibration but thermoelectric effects were a significant source of error, even at 350mA, and made lower-current secondary calibration points pretty much useless.
PM sent for code…….
PM sent.
PM Sent.
Just received mine. looks very nice…But I am charging it first… I guess it needs a driver to get the full output… That’s also coming…
More details later
Got mine today, nice!
Sofirn C8F v2.0 is the other name for Sofirn C8F 21700 version, isn’t it?
I had it in the cart with the coupon applied………deleted it. It looks like a nice light but I just couldn’t see the niche that it would fit for me. I mean, I like lights of all shapes and sizes, but before I click the “buy” button, I like to envision a scenario in which this particular light would outshine all others—so to speak. Ya know, a time and place that this light will do what my others can’t or at least do it better. Couldn’t find one. Maybe next time.
I waffled back and forth on this one for similar reasons, but $32 for a decent looking light with a good ramping UI with direct access to moon and turbo, a free charger and battery, and good modding potential was too good to pass up.
I sure can see that. It’s a good deal. Now ya got me thinking again………
Oh, just buy 1 or 2 and be happy. :laughing:
I got like 3 of the old/original C8Fs (excluding the eval sample), another 2 of the then-new C8F, and now a new 21700 version. They’ll join my C8 Army™. You can never have too many C8s. Or so I tell myself.
I was planning to mod a few (219s, 351s… yeah, like that’ll happen), but they’re just fine right out of the tin.
Dunno what’s the real output of this bugger, but when I need oodles, I’ll unholster my Q8. If 1200lm is enough, my SP32v2 will do. In-between, more portable than the Q8 but more oomf than the ’32.2, this’ll do quite nicely, and is way more pocketable than a Q8.
You’ll be glad you did.
Does this have their own firmware or are they using BLF firmware? Is the mcpcb DTP?
I’m waiting for a C8+ to come out. with 26650 Battery and single side sw.
They more comfortable in hand than the skinny 18650/21700’s.
Can’t see the point in just going from 18650 to 21700,
the 26650 instantly gives a much more comfortable grip B4 anything else.
We NEED to update the C8, it’s got a little Ho-Hum.
I picked one of these up. No idea what version it is… Got it on Amazon… Asked for the ‘new’ driver…I am not sure of this ones output, but sofirn is asking me all these questions about how do I know it’s not right…. So I guess you don’t automatically get an updated driver….
.
.02. Maybe I’ll just send it back and save for ZL700
only 2600 Lumens though which is lower than the 18650 version