this post was submitted on 29 Jun 2023
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The present linear drivers are also available in 12A, and have a FET. Whatever rating your driver is becomes irrelevant once the FET kicks in though, so most folks will go well past 10A with most emitters. Allowing one the option to put in a battery that may well get tripped by trying to draw 15-30A off of a 10A cell would seems more like a liability than a desirable feature.
If the user wants to have a more powerful light than a 10A cell can power, and is willing to give up the ability to use a battery they have no interest in using anyways, that should also be up to the user. Not all makers have to have the same set of features and specs, and not all lights are for all people. There's a reason why there are so many makers and such a wide variety of lights on the market. I don't see different things being different as a shortcoming.
"Intended usage" means different things to different people. And for a lot of makers, "intended usage" includes selling to people who aren't willing/able to pay $500-2,000 for a flashlight. Not all people who wear a watch wear a Rolex or Patek Philippe. As for the actual light design, some folks legitimately need powerful beams of light for only a moment or two, and not all who want a light that has that power use it only for "party tricks". Taking that away seems to me to compromise a light's usability more than allowing it with the caveat that thermal rampdown exists.
I don't think there's enough people buying boost-driven lights that also want to use protected cells to justify the cost of producing and storing such a low-volume part. However, there are people who would try running a protected cell in a linear+FET light without dropping the ceiling that would complain about their light shutting off when it trips the protection circuit. And while the Acebeam 21700 may have the ability to power a D4K, all it'd take is one person putting that same tube on a DT8K to have the same issue.
The fact is the D4v2 already accomodates one type of battery (the 18350) whose max current is 10A, so adding another shouldn't be different. And I can program the firmware to lock out the highest current levels, or maybe even have it detect the battery voltage sag and limit the current automatically. So more rationalizing. And you ignored that 30 amp USB-C 21700 that can handle anything the D4K can throw at it, if it could only fit in the light.
The Photon II is also a mature light. You can get knockoffs of it for 50 cents on ali express.
I don't know of another light comparable to the D4v2. The D4v2 does everything I want (plus some stuff I don't care about). The one thing missing is a 5mm longer battery tube.
An unprotected 18350 still has a surge rating that can operate the light at reduced levels long enough for thermal rampdown to drop it to lower levels with lower amp draw. A protected cell has a hard cap that shuts the light off completely. Dimmer Turbo is different from, "Hey, my light is broken! HANK SUCKS!". And you ignored the DT8K comment, as well as the logistics around something of such limited demand. The only way around it I can see, which is making it impossible to put the 21750 tube on a DT8K, runs into the same logistics problem. Like I said before, I might feel differently if all manufacturing were "print on demand", but as it stands, it makes perfect sense to me why it is the way it is. Besides, wouldn't a sleeve allow a protected 18650 to fit in a D4K?
Protected 18650 in a D4k is an interesting idea, might work, thanks. I will ask Toykeeper if Anduril could notice current limiting in a protected cell. If it a sudden dropout with no voltage sag leading up to it, then it might be difficult. Still, the same question recurs: why not support protected cells in the D4K? The current limit excuse is gone, with the 30 amp protected cells.
I see the space heater mode as similar to the disco lights, basically a party trick. I can do without both. The BC21R works fine on a protected cell and has a heater mode advertised at 1000 lumens. Bathroom comparison with the D4v2 says the D4v2 is brighter by maybe a half stop, but i have to compare carefully to notice the difference. Both are too bright (they wash out my vision) for close range use anyway, and they heat up too fast for steady outdoor use. A momentary turbo mode can be handy for outdoor distance spotting, but a D4v2 with 219a's and flood optics is the wrong light for that anyway. If I want a thrower I'll buy one for the purpose.
I do realize there is not much differentiation between BLF lights, so buyers look at the lumen spec and pick the biggest number, but some of us are more discerning ;). Anyway, Hank offers all those hardware options, so it seems like a simple matter for him that if you order a D4v2 with a 70mm tube, it can be set to lock out current draw above whatever. That should just be a software setting. I think it was Bill Gates who said 640 lumens should be enough for anyone (oh wait). Didn't you tell me that you yourself don't use the max level of the d4v2 for lighting? My D4v2 does (eyeball guess from BC21R comparison) around 1400, so if it becomes 1000 or a bit lower with a battery swap, I can live with that. I'm pretty sure it dims a little as the battery depletes anyway. I did the bathroom test with a just-charged cell.
I'm having trouble believing the linear driver pulls anything like 18 amps from the battery. That is 60+ watts, 15+ watts per led, and they are not rated for that. I may try some tailcap measurements. It is certainly a waste of battery power, since the leds are way less efficient at such levels. It solves an imaginary problem.
My brightest light really is a 3D incandescent maglight (the notorious Ultimate Stealth Light from CPF). It uses a handmade high current nicad pack and a 100 watt slide projector bulb for around 3000 lumens. You can feel the air around it get warmer when you turn it on. I never use it though.
I don't see what the DT8K has to do with this. I don't particularly want a DT8K.