TK's Emisar D4 review

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leestrong
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zak.wilson wrote:
To sum up for those who don’t read C, it checks for low voltage every 16ms and steps down if it detects low voltage four times in a row. That’s many times slower than the PWM and should be sufficient to prevent spurious stepdowns.

Assuming the PWM and measurement is not synchronized. So, sometimes it samples at FET off, sometimes samples at FET on, the probability is the duty cycle.

At 50% duty cycle, the expected number of samples to get 4 consecutive FET ON measurement is 14 times, ~0.22sec.
At 10% duty cycle, the expected number of samples to get 4 consecutive FET ON measurement is 11110 times, ~3mins.
At 5% duty cycle, the expected number of samples to get 4 consecutive FET ON measurement is 168420 times, ~45mins.
Hmmmm…..
May I suggest to use moving average on the sampled voltage.

If measurement and PWM are exactly synchronized, it could alway be measuring at ON or OFF.

Agro
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When I said “weak” I meant “low current”, definitely not 30Q. And so I did a test with 18650B charged to 3.6V.
Turn on, 350 mA. Increase slightly, wait short while, no effect, shines OK. Ramp up all the way to turbo – still OK. Gets warm very slowly compared to VTC6. Run fine until thermal protection kicked in, then I stopped the test. It took forever to warm up, like 30 seconds.
So I was wrong, the D4 is fine with a weak cell.

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gregor
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ven wrote:
gregor wrote:
Agro wrote:
What batteries are you using and are they fully charged?

I just found out that all my INR18650-30Q cells have only around 3,40-3,50V. Now they are all in charger.
Will report back if this will fix the problem. Most likely it will.

Thank you for your help.

That will do it! I find a couple of spare ready to go 30Q’s work with this light………….does not take long to get the V down into the mid 3’s. Swap out and carry on the fun Smile
What would work better is having 3 x D4’s , that way the spare cells are housed for instant WOW Big Smile

30q fully charged, now the FL works very well, it gets got very quickly Smile

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gregor wrote:
ven wrote:
gregor wrote:
Agro wrote:
What batteries are you using and are they fully charged?

I just found out that all my INR18650-30Q cells have only around 3,40-3,50V. Now they are all in charger.
Will report back if this will fix the problem. Most likely it will.

Thank you for your help.

That will do it! I find a couple of spare ready to go 30Q’s work with this light………….does not take long to get the V down into the mid 3’s. Swap out and carry on the fun Smile
What would work better is having 3 x D4’s , that way the spare cells are housed for instant WOW Big Smile

30q fully charged, now the FL works very well, it gets got very quickly Smile

Yes around 15s from cold, once it been used in WOW mode, heat is almost instant from there on(used within minutes). Glad sorted, worth checking the V a few times after a few uses to get an idea . Then when out, will not get caught out as easy with low voltage if makes sense.

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Recently I found another thing about what PWM does with a li-ion. I have a little 10440 copper Maratac with an XP-L2 running at 3A on high, while the little Efest battery at 3A has only 1/3 the capacity of the same battery at 1A (HKJ’s test). It is a simple FET driver so on low setting it alternates (18kHz) between 3A and 0. I expected the runtime to be consistent with the lowered capacity at 3A but instead it was about 3 times longer, like it had experienced a current of 1A or less. I was pleasantly surprised because the lowered runtimes was my main worry of using a FET driver.

I have two possible explanations:
1) the PWM is so fast that the peaks do not end up fully at 3A, this could be checked on a scope
2) the lowered capacity of the Efest 10440 at 3A in HKJ’s test is caused by heat, the PWM-ed low setting never heats up the battery.

Or else, something else is going on chemically in the battery.

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Tonight’s play things starring the D4

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patmurris wrote:
In both case, the memorized level was forgotten and one of the shortcut has become redundant. I would have expected the memory to persist until some ramping occur.

Perhaps in the future it can do that. IIRC, Tom’s NarsilM already does it… but this was kind of forked from an earlier Narsil and simplified.

maukka wrote:
CRI / drive measurements

Thanks! It seems CRI is not completely straightforward, but the cooler-when-brighter trend appears to be fairly consistent at least.

leestrong wrote:
7135 efficiency

Yes, 7135 chips do not attempt to convert extra voltage into current. They burn off the extra voltage instead. Same with a FET. A voltage-converting driver should be more efficient when the battery is full and emitter Vf is low, like a 219c with a full li-ion cell. The same voltage-converting driver will generally be less efficient when the two voltages are very close together though, and it’ll generally have lower maximum output. Even without accounting for size, there are tradeoffs.

In actual usage though, I don’t generally notice the difference in runtime since it happens in many short sessions spanning weeks or months. Like, I don’t often notice whether it gets 10 hours on medium (D4 XP-G2 @ 160 lm w/ 3500mAh cell) vs 11 hours (Zebralight SC600w Mk II L2 @ 150 lm w/ 3400mAh cell).

Agro wrote:
Want 200 lm? On a weak battery you can’t have it.

Not true, as testing showed.

hIKARInoob wrote:
  • 200 lumens with FET drive using PWM means you’re getting the low efficacy of the led at the max output of ~3500 lumens.
  • 200 lumens with FET drive using PWM means you’re getting the tint that you get at max output of ~3500 (which could mean bad news).

This is how it would behave if it were a digital system, but it’s not. The behavior is analog. At 200 lm, the FET pulses are not full power. It rests at 350mA most of the time, but has very brief spikes which go higher. As earlier testing graphs showed, though, those spikes don’t reach maximum power until a significantly longer duty cycle.

So at 200 lm, or any medium-high level, the efficiency and tint do not match turbo, and they don’t match the 7135-only level. It’s in-between.

At higher duty cycles, like 1000 lm and above, the FET likely does reach full power during each pulse, but the overall efficiency, tint, and sag are still in-between because there are so many analog components involved. And because it’s still spending part of its time at 350mA, part of its time at 15A, and part of its time between the two.

djozz wrote:
the PWM is so fast that the peaks do not end up fully at 3A, this could be checked on a scope

IIRC, maukka scoped this on the D4 a few pages ago and found that theory to be true. The pulses have a slow enough rise and fall time to act as a very weak lowpass filter, so short pulses never reach full height. (edit: scoped output, but that works because the LED activation time is much faster than the FET driving it)

Quote:
… interaction between PWM and measured voltage …

The voltage samples are taken at clk/128 speed, which IIRC gives somewhat of an analog average of 128 sequential time slices. PWM takes 512 time slices per cycle. To get 128 FET-on time slices in a row, it would have to be at a ramp level of 101/150 or higher (where FET PWM=66/255).

So… the hardware’s measurements have a lowpass built in. And then it has another lowpass in the measurement logic. And another lowpass in the LVP logic. It’s not prone to triggering LVP due to measurement noise. If Tom’s comments are correct, the firmware takes four measurements per second. If four values in a row look too low, and it didn’t step down within the past few seconds, it’ll step down. I think I may see a bug in the code for that, but it isn’t one which has any significant symptoms.

The short version is: LVP works normally, even when the momentary voltage levels change dramatically from one microsecond to the next. Development included real-world testing.

Agro wrote:
the D4 is fine with a weak cell.

As long as the cell’s protection circuit doesn’t trip, yes. It works fine even on weak primary cells like a CR2032, unless you try to use turbo. In that situation, it will (correctly) trigger LVP until the output is down to a level the cell can manage, and then run happily until the voltage is actually low (low for li-ion).

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Anyplace we are keeping suggestions for a V3 of the software?

1) Inserting batter for first time – Make double blink moonlight or not necessary (If you lockout at night with unscrew of cap, blinding flashes in the dark are not desirable)

2) Don’t memorize settings which have shortcuts (moonlight and turbo)

3) Allow for a memorized output setting set by user

Those were a few of mine and another person’s that I really liked. I know there were more, but can’t find them all. Thanks!

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Another change, not so much for the better…

I put 4 Nichia 319AT on Richards board and reassembled the D4. Now it pulls 13.85A for 3015.3 lumens on the “B” cell and 20.22A for 3677.7 lumens on the “A” cell. The beam pattern is nice and smooth, round, but with that odd discolaration in the center we’ve seen with the Cree XP-G3. Low on both cells is a fairly miserly 0.72 lumens.

specialk
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Just pulled the trigger for #3 d4

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Tixx wrote:
Anyplace we are keeping suggestions for a V3 of the software?

Well, there is a bug tracker attached to the firmware repository… that might be a good place.

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DB Custom wrote:
Another change, not so much for the better…

I put 4 Nichia 319AT on Richards board and reassembled the D4. Now it pulls 13.85A for 3015.3 lumens on the “B” cell and 20.22A for 3677.7 lumens on the “A” cell. The beam pattern is nice and smooth, round, but with that odd discolaration in the center we’ve seen with the Cree XP-G3. Low on both cells is a fairly miserly 0.72 lumens.

I have found that odd discoloration too in a quad 319AT driven hard. Kinda Grey on the spot. I was going to try the 18350 Aspire once I receive the tubes and batts. If that fails I will go regulated. I don’t find them worthwhile driven hard. I may or may not have used one in an NiMh AAA. Need to look. Maybe I just thought about trying it.

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I plan to use 4 of the green XP-E2 when Richard gets the short tubes in, then it’ll be a little green meanie, running on the 18350 Aspire. I personally like blue output better, but the greenout seemed like the way to go and I haven’t done anything like that before lol.

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Can anyone comment on the objective/subjective differences between all the NW options? Ideally I like pure white or a little rosy with high CRI. No purple to yellow transitions. Or should I wait til better emitter, probably Nichia, is introduced. Most recent purchases have been Nichia. Or if this has been discussed at length earlier, please point me in right direction. Thanks and Cheers!

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leestrong wrote:
hIKARInoob wrote:
It’s frequency/algorithm related that the DMM is likely not able to give the correct value (I think). But would an analogue volt meter give the correct value?

To see the voltage fluctuation under 15kHz PWM, we need something with sampling frequency higher than 30kHz, store the samples, and show the curve on a screen.

No!
You need a sampling frequency 5 to 10 times of 15kHz
Nyquist is only for pure sinus forms and PWM is more rectangular form. With only double, you don’t know what you’re measure

leestrong
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joechina wrote:
No!
You need a sampling frequency 5 to 10 times of 15kHz
Nyquist is only for pure sinus forms and PWM is more rectangular form. With only double, you don’t know what you’re measure

Of course, I meant 30kHz is necessary, but not a sufficient condition.
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Nite Shadow wrote:
Can anyone comment on the objective/subjective differences between all the NW options? Ideally I like pure white or a little rosy with high CRI. No purple to yellow transitions. Or should I wait til better emitter, probably Nichia, is introduced. Most recent purchases have been Nichia. Or if this has been discussed at length earlier, please point me in right direction. Thanks and Cheers!

As it stands right now, none of the emitter options is really satisfactory for me. The Nichia is too cool and has too low CRI. Both the XP-G2 3D and 5D has a purple corona and yellow spot.

If I were you I’d buy the 219c and if you don’t like it reflow to high CRI LEDs. Or if you don’t know how, send it to someone who can.

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Nite Shadow wrote:
Can anyone comment on the objective/subjective differences between all the NW options? Ideally I like pure white or a little rosy with high CRI. No purple to yellow transitions. Or should I wait til better emitter, probably Nichia, is introduced. Most recent purchases have been Nichia. Or if this has been discussed at length earlier, please point me in right direction. Thanks and Cheers!

the 219C in the D4 are pretty White. Also under the quad optic the bean pattern remains uniform in color to the edges.
I don’t have an XP-L HI version to comment or compare. But that might be another option as White. Xpl Hi do pretty good under an optic.

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Sledgestone wrote:
Nite Shadow wrote:
Can anyone comment on the objective/subjective differences between all the NW options? Ideally I like pure white or a little rosy with high CRI. No purple to yellow transitions. Or should I wait til better emitter, probably Nichia, is introduced. Most recent purchases have been Nichia. Or if this has been discussed at length earlier, please point me in right direction. Thanks and Cheers!

As it stands right now, none of the emitter options is really satisfactory for me. The Nichia is too cool and has too low CRI. Both the XP-G2 3D and 5D has a purple corona and yellow spot.

If I were you I’d buy the 219c and if you don’t like it reflow to high CRI LEDs. Or if you don’t know how, send it to someone who can.

Does the XP-G2 D3 still have a purple corona at 600 to 1000 lumens?

Most of my usage would be around 600 and maybe bumped up to 1000 lumens.

Thier ain’t no bones in a hot dog. F. York

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Yes, it has the purple corona all the time. Regardless of output level.

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Sledgestone wrote:
Yes, it has the purple corona all the time. Regardless of output level.

Oh man.

What are the tint snobs that prefer the rosy 4000K to 5000k swapping these out with?

BTW, tint snob is a compliment. Thumbs Up

Thier ain’t no bones in a hot dog. F. York

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If you want rosy I’d say 219b. But I still haven’t tried my 3D with frosted optics yet maybe it’ll make the tint better.

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Sledgestone wrote:
If you want rosy I’d say 219b. But I still haven’t tried my 3D with frosted optics yet maybe it’ll make the tint better.

Thanks.219b be able to handle the high current of this driver?

Thier ain’t no bones in a hot dog. F. York

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It shouldn’t be a problem. But the output would be much lower than it would with 219c. Hopefully more knowledgeable members can chime in here.

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The 219B will work but may not really like the heat that this light produces. The Vf is just as low as the 219C so it draws just as much current (15+amps), and with lots of extra heat stress because of the small host. I’d say 219C is the safer bet.

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The N319 has a slightly warm tint, nice round beam with few artifacts (kinda have to spin it around looking at a white wall or ceiling to see the standard quad optic stuff)

At lower levels the overall tint is nice, there’s that off color hot spot when cranked up but it’s not much of a big deal when using it especially outdoors. It’s nice to have the cooler running light, 4 219 C’s on a 20700 is pretty intense. It’s noticeable how much longer it takes to really start heating up, so the 319 has merit in the big picture.

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Picture from a previous post :

D4 Nichia 219C 4000K CRI92 (left) X5 Nichia 219C 5000K (right)

I use to love the 5000K tint, but now the Nichia 219C 4000K tint looks more neutral to me.

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khas wrote:
Picture from a previous post :

D4 Nichia 219C 4000K CRI92 (left) X5 Nichia 219C 5000K (right)

I use to love the 5000K tint, but now the Nichia 219C 4000K tint looks more neutral to me.

That’s what I want 219c 4000K. Looks great!

Thier ain’t no bones in a hot dog. F. York

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djozz wrote:
The 219B will work but may not really like the heat that this light produces. The Vf is just as low as the 219C so it draws just as much current (15+amps), and with lots of extra heat stress because of the small host. I’d say 219C is the safer bet.

Words of Wisdom…
…..within a relatively short period of tests with my experimental D4 (with Nichia 219b sw40 9050 – 93 CRI)
one of the leads to the stock MCPCB easily managed to relieve itself.

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