TK's Emisar D4 review

He has 43 left as of right now. I’m not sure which emitters/tint/body colors/ are still available but there are 43 D4s as a total left at Richards site.

Ordered my D4/3D from Mtn, at breakfast, shipped by lunch. Can’t beat for service. :+1:

I’m NOT ordering a second D4! NOT NOT NOT NOT NOT NOT NOT.

Fine, Skip the second, go right to the Third.

Back almost a dozen pages, ven mentioned about how he was running through 18650 cells in no time and I thought I’d take a closer look into the ability of my D4 to work with smaller cells.

I have been spending time alternately using my new Desert Tan Convoy S2+ and my D4 but not using either seriously or for any real extended period of time. I had my D4 loaded with a purple Efest 700mAh cell and tried out the battery check. After very little use (mostly lowest mode to read by at night and a handful of times running it through the ramping and showing it off) the cell was already down to 3.8 volts. I had barely used it.

Even though it looked so cute with the smallest tube (and the purple Efest completing the hulk look) I’m back to the 18650 tube, Convoy clip and either a GA, VTC6 or 30Q. I’m hoping these will last at least four times as long, which may not be all that long in the real world…

Still love this little powerhouse.

At about 15 amps, a 700mAh cell would only last 3 minutes. Probably less, really, since capacity is less at high amps. It could probably drop a 18350 cell to 3.8V in under a minute of turbo.

However, the same cell should last for 2 hours at the max 7135 level, or for about 3 days on moon. Closer to a full day at the ‘low’ level I find most useful.

So… runtime of anywhere from 2.5 minutes to ~3 days on a 700mAh cell, depending on how bright it’s running. With an Aspire cell, it’s more like 4 minutes to 6 days. With a 3000mAh 18650 cell, more like 9 minutes to 15 days.

This can be maximized by starting each session with a long press, and releasing as soon as it gets bright enough for the current situation — bright enough but no more than necessary. Then turn it off and on with a single click until you’re done. Turbo really is only for bursts, and will eat through batteries like there’s no tomorrow. Every second spent in turbo uses about as much power as about 30-40 minutes on moon. If you show off turbo three times for three seconds each, that burns four to six hours of moonlight.

TK, your first post of this review mentions over 4,300 lm with XP-L HI.
But it doesn’t tell which tint do you use. Cooler is V3 flux, warmer is V2. Could you clarify?

Hello

I need your help. I have next problem. When I turn on the light and put it at 30, 50,75…% it always happen next: after 5 secondes light flashes 3 times and lumens are reduced, this is repeating every 5 secondes and lumens are again reduced. This cycle is repeating few times till FL reach 1 lumen or very small amount.

Do you maybe know what is wrong? Do I have defect FL?

Thank you

What batteries are you using and are they fully charged?

Man this data is really making me reconsider my change to a FET + n + 1 driver…

It doesn’t seem like it would actually be much more efficient, but I guess the regulation would at least be nice.

The problem is not at all the amount of regulation but the sheer output: you want 4000 lumen?; then your pour single battery is sucked dry in 3 minutes! You want 4 lumen to read your book? (The beam is great for reading a book) You have 50 hours, enough to finish half the Potter series.

I’m actually not too interested in the 4000 lumen output, but I was hoping to be able to get say 1000 lumens of stable output with significantly longer battery life at ~300-400 lumens.

Looks like the 7135s may put out too much waste heat unfortunately.

@djozz
Want 200 lm? On a weak battery you can’t have it.

What D4 does now puts out even more heat at the same lumen output.

Right I’m aware that a FET + 1 is horrendously inefficient at medium modes, but it looks like a FET + n + 1 isn’t that much better.

I was hoping to jump from 67 lm / W to around 110 lm / W at ~400 lumens, but it looks like it’s going to be more like 80 lm / W.

I guess on the plus side, efficiency will improve as the battery drains. Maybe I should look into IFR batteries?

I have not checked that (I suppose you have?), but does that really happen? I understand the theory: PWM-ing 15A output to get the medium modes has the potential to get under LVP voltage early because of the voltage sag under that load, but has anyone checked that this really happens at the point that the battery still has a significant charge?

I don’t think this will happen. I don’t think it will draw 15A. Theoretically if you want half the output using PWM, it should draw about half the amps, so about 7.5A (slightly non linearity). At least, that’s my guess.

Edit:

- 200 lumens with FET drive using PWM means you’re getting the low efficacy of the led at the max output of ~3500 lumens. Efficacy of the same led at 200 lumens using current control is much better.

- 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). Tint of same led at 200 lumens using current control is “regular” tint.

  • Ampdraw, and voltage sag when getting 200 lumens with FET drive using PWM is not the same when getting max output of ~3500 lumens, but is directly proportional to the amount of time FET is open. So 50% open means 50% of max drawof ~15A.

Well that’s how I see it. Ok maybe I’m not understanding something?

I have not tried, will later today.

No. It will keep shifting between 350 mA and 15A.

Exactly. But this occurs so fast, that what the battery actually feels is the effective value. So when the FET is 50% open, then the draw will fluctuate between 350 mA and 15A, but effectively will be around 7.5A. And this value determines voltage sag, and not the value at 15A.

Ok, started a check.

D4 set at output 200 lumen (leds are 219C 3500K 90CRI so the current is a bit higher than with stocks leds at 200lm), on a 30Q battery starting at 3.54V (so well over half drained). No protections kicking in yet, waiting for things to happen :slight_smile: