No, there is not enough place for one that youd like.
ну и нах тогда он не нужен)
I agree DD and PWM suck a little…
I highly prefer constant current drivers.
Of course a constant current Boost driver would be ideal, like what zebralight, armytek and olight uses for their high power headlamps, But for $35 and this compact size I don’t think there’s is reason to complain about pwm to achieve this level of output.
I am very interested, will be on sale in intl-outdoor? or will be only for US people (the shipment from ME is around 15 USD for my country).
Regards (for the price of 35USD seems fine for me, is not perfect but is very nice and powerful with a good interface!)
I haven’t bought a light in a few months but ill buy one of these i want to do a EDC review video. It seems like a light that may fit the market well seeing as lumen numbers always sell.
I don’t know.
Seems to me they could have used something like the LD-2 driver.
Shouldn’t be a lot more expensive to produce.
Price may be good but the current driver (heart of any flashlight) isn’t interesting at all. To tell the truth it’s not even 1% of what most of us expected. Have you ever seen M43 customs? Nope, because the native driver is worth to be respected. There’s only one hope left, a decent case with customization features 
The D4’s ramping UI, combined with its high amperage, doesn’t generally work well with constant-current drivers. The way power is regulated on constant-current drivers tends to make middle levels hot and risky, requiring either limited output or direct heat sinking on the driver.
A Meteor-style driver is too big for the D4, and not ramp-friendly. If I understand correctly, the Meteor gets safe middle levels by having multiple regulators each running at 100%, which is safer than having a bigger regulator running in a mid-range. This gives it the ability to have several regulated levels in a stair-step pattern by turning components on and off. However, it doesn’t allow anything between the stair steps for more than a second or so, because it risks overheating.
The led4power drivers are much smaller with a single rampable regulator, but they have both of the complications which go along with that — limited amp ceiling and heat issues on mid levels. Also, it kinda needs a separate regulation circuit (or maybe PWM) for low levels and moon. It’s pretty close though, especially if you don’t want completely maxed-out lumens, and similar open-source designs might be a good option in the future. That effort has already started with the BLF GT driver.
The D4 uses a proven and popular FET+1 solution instead, which allows safe and smooth ramping with no driver heat issues, but its runtime graphs on medium and high levels won’t be as flat as a fully-regulated driver. Not that anyone would notice this during use, considering that it ramps smoothly to whatever level the user wants.
None of these solutions is perfect; there are tradeoffs in all cases. I think Hank picked a good set of tradeoffs though, and I’m happy he went with a solution which is simple, powerful, and uses my favorite type of UI. Those things matter to me more than a perfectly-flat graph.
^
Many thanks for the in-depth science. I’m definitely one of those OCD fools drooling over perfectly flat run-time data. And I certainly don’t care for FET drives for that reason. But we also know that the excellence of the M43 is definitely not a result of an accident or luck; everything is well thought off. It is what it is, is often said here on this forum, and it certainly is applicable here as well.
I just have so much confidence in Hank that I’m convinced the Emisar models are going to please me a lot. Of course time will tell. :partying_face:
(Of course Hank needs to sell the lights to me first instead of giving everything to Richard, hehe 
)
That’s true.
The generated heat on medium modes (or rather high Amperes combined with big voltage difference between battery and LED, which can also occur on high mode) being the risky thing…
You’re muddling cause and effect here.
Ramping isn’t something particularly desirable by itself, it’s only a crutch to make unregulated FET drivers at least somewhat comfortable for ordinary use when you need stable output for a duration of time, not a quick wow-flash.
Constant current drivers don’t need ramping because they already can maintain their output level without any user intervention whatsoever. While direct-drive FET drivers are practically useless without it.
Same for me.
Especially when you’re forced to un-optimize the electrical path to prevent too high currents with a freshly charged cell, then i don’t like the idea at all.
Maybe in the future there will be high capacity LiFePo cells and lower Vf LEDs to make perfect combinations, since LiFePo have a near flat discharge curve.
We’ll see. 
So, you wanna say, that linear driver has better heat performance and efficiency on high power rather than boost? FET+1 is less addicted to overheat, so why? It’s much more important how the driver thermal interface developed is. Everything depends on developer. How about stabilization?
Well M43 driver is big because it’s calculated this way for required output power but there are other compact boost drivers. You can smoothly adjust the mode in M43. Have no idea what you meant about M43 ramping, really.
@Reyden
Do you mean a boost driver for 2S2p LED configuration (for this D4 light)?
It will need a big inductor and diode, i think that will use a lot of space…
Actually a quick WOW-flash is what I want from this light. I used to have zebralights, armytek and eagtac lights all with constant current, but for my EDC I chose to go with a modded jetbeam mk II with a FET+1 and XP-L HI, because of the wow flash. For any other “serious” situations I bring a larger light that can handle the heat at a regulated output. Can’t speak for the others though.
I thought ramping is more of a desirable feature rather than a needed one to maintain output? It’s not like the user will have to ramp up manually to regulate the output.
…
Me too consider a 4S boost driver would be ideal for this light, but it’s a bit unfair for the FET+1 to be receiving all the bashing.
Ramping with an e-switch…
Hmm… Always ramping too far up or down, or not far enough, or you need slow ramping maybe…
We’ll see, i think i’ll buy a grey 18650 D4
Two stage camera switch, like in the Nitecore Tiny Monster lights. Half press is slow ramping, full press fast ramping.
No, I suppose the best way is 4S for this flashlight. Yeah inductor takes a lot of space but compromise can be found. But seems it’s too late 2S2P also accepteble. Other question what is desirable output power…
Who said that ramping is “must have” function? Reasonable modes that’s what important.
FET+1 for marketing, profit and wow effect, nothing to add. 18-20W is more than enough for such flashlight .
Potential buyer it’s not about me so have no idea what im doing here
Yeah, 20 Watts should be enough, it will get very hot very fast on 20 Watts too.
…but we want 30 or 40 Watts, i think… 
I don’t know… I think i’ll buy one anyway. :innocent: