KW CSLNM1.TG isn’t gonna last long

Hoop · 2019-01-19T15:04:51.000Z

If you have an LED that you don’t want to ever feed more than say, 6A, then a 6A linear regulator is going to burn off the voltage beyond that in order to bring the LED current down, but once the battery voltage drops enough, it essentially becomes direct drive minus some dropout voltage, and some linear drivers have almost no dropout. Current limiting is pretty much a requirement with LEDs that will be overdriven or destroyed if fed ~4.2V, which is most of the current gen of LEDs. It is of course possible to get the balance of components just right with springs, wires, cell selection, to keep from damaging certain low Vf LEDs in DD, but some new LEDs are extremely low Vf, so it’s just not a good situation.

Barkuti · 2019-01-19T15:12:40.000Z

n10sivern, let me say the actual price of regulation is just the sense voltage times current or the square of current times sense resistor, which is a small amount of heat in well designed drivers. If performance is what you aim for I understand your points, though, but please consider you cannot obtain peak performance for long if unregulated, only when battery voltage is about right on spot. To increase this peak performance window you need to first overdrive the emitter.

For such duties I'd build fully regulated, albeit I can understand it needs DIY tuning. In this case I think an LD-29 buck driver fed with 2S cells could do, its stock output is 3A but I think it'll do fine at 5+A. A couple 68mΩ sense resistors over the stock R025 would net ≈5.206A, for example, though personally I'd probably leave it at 4.5A with just an additional R050. When fully regulated current at the emitter never drops so I'd recommend not pushing the current values to peak ones seen on output tests because lack of cooling.

Cheers ^:)

n10sivern · 2019-01-19T16:08:03.000Z

Hoop, I agree. I don’t use high drain batteries with low vF. I used a protected battery that doesn’t have a high discharge rate when I first powered the LED. I saw the dark spot, got mad, and my goal is to now torture that LED up and replace it. I didn’t test the current but I doubt it was over 4A.

Barkuti, I don’t want 2S lights for hunting. Too long to use mounted to a rifle. LD29 is also inefficient. You could add resistors to get to 5A theoretically, but it’ll actually be 4.5A. I don’t worry about cooling as I don’t run the lights for an extended amount of time, which is why I am not worried about peak performance for an extended amount of time. I always have plenty of batteries, and I change them when I notice a drop in performance. In a night, I may use the light intermittently for 20 minutes total when hunting. With hogs, I generally spot with night vision and IR, and switch to white light at a distance once I identify a potential target. I run linear drivers on my IR’s pushing them at 2.28 or 2.66A. I’m working on a water cooled IR that I will try to push 4A just for the hell of it. I build my lights for a specific purpose, and I don’t use them outside that purpose. I have lights built specifically for tracking/flood beam, spotting (red and IR), long distance shooting (white), etc. I don’t have or want a do it all light. I also don’t use reflectors much. Most of my lights are aspherics, and my flood lights are DD triples with Ledil optics. What few reflector lights I have are typically used for jsut around the house, with an exception of a DD MTG2 that is running at over 10A. Every time I try to test the current it blows the fuse in the tester. I built it just for giggles. I run regulated drivers when it suits my application, and DD when I feel it is necessary.

Lexel · 2019-01-19T17:34:45.000Z

there is absolutely no advantage of a DD driver for this LED!

tons of disadvantages
even if you limit the current you get full brightness only with full cell then dropping by 10-15% in the first 5% of battery capacity and slowly dropping with further discharge

Using 1S L4P CC driver gets you over a lot of the battery capacity full output,
or
MTN 2S buck,
my 2S Buck drivers
with proper firmware and current gets you over full output till the cells hit LVP under load

DD has its place for multi emitter lights or XPL HI single emitter where you can not cook the LED even with best battery

BlueSwordM · 2019-01-19T17:36:04.000Z

I perfectly agree with Lexel.

Using a CC FET driver, or a buck driver would be much smarter, and cost you less in the long run, since you will not have to kill an LED.

LouieAtienza · 2019-01-19T18:05:42.000Z

Lexel:

DD has its place for multi emitter lights or XPL HI single emitter where you can not cook the LED even with best battery

I have to say, I have a bunch of XP-L HI LEDs and I have retrofit them on a lot of my (and friends’) lights because they seem to be un-killable and just work in many situations…

n10sivern · 2019-01-19T18:21:01.000Z

I agree and I wouldn’t normally run this light with a DD but I didn’t feel like digging out another driver. The driver didn’t damage the LED, but I’m gonna make sure it does. And as I said before, I own very few 2S lights and don’t like the inefficiency of buck drivers. What 2S lights I have run 6V LEDs. Everybody is harping on the driver, but it’s a non-issue. I have linear drivers and I’ll likely use them when I actually do a legitimate build with this LED, but this was for fun and the LED was damaged goods before the driver. Regardless, I was going to push the LED to it’s limits, but now that it was damaged from the factory or reflow, it’s destined to die.

Lexel · 2019-01-19T18:16:15.000Z

n10sivern:

I agree and I wouldn’t normally run this light with a DD but I didn’t feel like digging out another driver. The driver didn’t damage the LED, but I’m gonna make sure it does. And as I said before, I own very few 2S lights and don’t like the inefficiency of buck drivers. What 2S lights I have run 6V LEDs.

you can simply stick 2 1100mAh 18350s in a 18650 light and have your 2S buck driver

n10sivern · 2019-01-19T18:33:45.000Z

Lexel, please explain why I want to buy batteries I don’t already use so that I can run 2S with an inefficient buck driver and less battery capacity when I can just run an 18650 with a linear or DD driver.

Lexel · 2019-01-19T18:44:31.000Z

n10sivern:

Lexel, please explain why I want to buy batteries I don’t already use so that I can run 2S with an inefficient buck driver and less battery capacity when I can just run an 18650 with a linear or DD driver.

Why do you quote a buck driver unseen inefficient?
Burning overhead voltage in FET or with DD with no bypasses, high iR cell and thin wires has ecxactly the same result on efficiency

a 90-92% efficient buck driver with properly bypassed springs and high drain cells should be not less efficient than any other driver concept

you mainly burn overhead voltage on this LED from 3.3V to about 3.8-3.9V on battery
simply do an efficiency calculation on this and you will see how inefficient your DD gets

so lets do the math for you I get to 86% efficiency with full cell with 3.3V LED and 3.85V from battery
with lower cell voltage and less current that efficiency goes up, but also on a buck driver on medium currents this is the case

but if we start too look into your medium modes with full cell
DD is PWMed while CC Buck driver gains extra efficiency as it does not drive the LED on full current, so the losses in the wiring are reduced and the LED runs more efficient

as a summary often in medium moded and full current the Buck driver beats any DD driver,
the only advantage has DD+7135 at very low moon modes where its naturally more efficient as no buck controller has to be used which got some static losses which do not decrease with current

n10sivern · 2019-01-19T19:12:05.000Z

Buck drivers can be inefficient, especially the cheaper ones. More expensive well made ones can be efficient. I’ve never felt the need to use the more expensive ones when I have other cheaper options to use. I have never seen where I will significantly benefit much from them to justify spending more.

I don’t just have DD drivers. I have linear/regulated drivers as well. I don’t use any mode other than high in my hunting lights. I have a couple of lights with no driver at all, just a contact board and wires. I only have one light with moonlight, and I rarely use it. My lights are either about how far will it throw or how big of an area will it light up full throttle. I have numerous liner and DD drivers with guppydrv on them but they typically stay in 100% mode only. The only lights I use in other modes are the ones I keep around the house that rarely get used.

Pöbel · 2019-01-19T19:29:15.000Z

i can understand your point. especially when you have NVGs the need for low power lights decreases.

I can also relate that just for spotting a kiss solution can be absolutely sufficient.

It’s just different use cases requiring different tools

n10sivern · 2019-01-19T21:18:22.000Z

At least somebody understands

Talpa · 2019-01-19T23:44:54.000Z

Good post. As a hunter I totally understand your points. For real, the stock C8+ with 100% mode only is what is totally enough for hunting purposes for me. But I built one with white flat. And now all my hunter friends are wanting one too

n10sivern · 2019-01-20T00:04:19.000Z

We have a hog problem and a 1000 yard long field so I need lights that throw like a big dog.

teacher · 2019-01-20T00:13:35.000Z

n10sivern:

At least somebody understands

Hey, I understand. You have something that works for you & your sticking with it. :+1:
I imagine you have plenty of hog kills racked up to your credit to not feel the need to change a thing.
Ever need or want another gun I’m available…. . I have just about recovered from the absolute shock of ’The Game’…. :cry: . :person_facepalming:

Talpa · 2019-01-20T00:14:27.000Z

I understand the negatives, but otherwise I’d love to hunt that way. Most countries in europe night vision and lights for hunting are forbidden. Ok, you can spot animals with night vision, thats difficult to ban.

Enderman · 2019-01-20T00:18:16.000Z

n10sivern:

At least somebody understands

I think what you don’t understand is that driver efficiency is not the same as overall efficiency.
Yeah direct drive is technically 100% efficient since no power is being lost by the driver, but you’re losing tons of efficiency by not driving the LED at the peak output, it’s almost always before or after the peak of the curve.

So even a crappy 75% efficient buck driver that regulates the current would offer better performance and runtime than the inconsistent direct drive strategy.

teacher · 2019-01-20T00:21:24.000Z

Talpa:

I understand the negatives, but otherwise I’d love to hunt that way. Most countries in europe night vision and lights for hunting are forbidden. Ok, you can spot animals with night vision, thats difficult to ban.

For game animals it is forbidden here to Talpa. But for wild hogs just about anything goes here. They are invasive & populations are growing in leaps & bounds. They are devistating farm land & crops here in much of the USA & open season has been declared on them. Otherwise they are going to take over. In many place they almost have already.

Talpa · 2019-01-20T00:35:36.000Z

Here the biggest fear is african swine fever. Many countries have legalized lights in wild boar hunting because of that. Latest here in Finland also.