What is the smallest host that could drive a single 219B effectively at max output (3 to 4A)?

You can gain over a 100 lumens between 2 and 3 amps. Don’t know if you will notice, but it is still a reasonable amount.

Human vision cant see difference in bright light changes same as in low. You will see noticeable brightness change jumping from 1 to 3 amps, but not really from 2 to 4. If you want mooorrr lumens use triple or more powerful led.

You’re moving the goalposts now Quadrupel: you stated max output is at 2A and that’s just incorrect. As for why I don’t consider a triple or more powerful LED: I prefer the beam profile of a single emitter in a reflector, and I like the tint of the 219B. I’m not asking about efficiency.

You are wrong and Quad is correct.

Absolute maximum forward current is listed as 1500 mA, and pulsed is 2000 mA.

219B datasheet

But i don’t care or have a horse in this race—run ’em at any current you want.

Who cares? The experimental data I linked above shows that maximum output is at 4A. Manufacturers list very conservative current limits, which for my purposes can be disregarded. In a similar vein, battery manufacturers such as Samsung state that their products should never be sold on their own to the end user but who listens to that?

Anyway I’m looking for a discussion about hosts, not whatever this is.

Probably you should care, because such tests aren’t really done with small hosts, but usually with big chunks of copper, which weight more than the entire flashlight, sometimes even with active cooling.

Some examples.

You’re right that the tests aren’t done in a flashlight, but the manufacturer isn’t testing in a flashlight either.

OK ignore the 219b bit, what’s the smallest host that could drive a mystery 3V LED at 3A for a sustained period?

Depends on environment temperature and host capability to radiate heat

What about Convoy T2 (T3) host and Convoy 17mm 2800ma driver?

I say Convoy L2 head will do the job :slight_smile:

If you don’t have anything constructive to add please stop posting quadrupel

I’m running a dedomed Nichia 519a 3500K R9080 (2800K dedomed) at 5 amps in a Convoy T2 host with a Vapcell H10. Is it a great idea? Probably not. Does it work? Yup. Does it heat up really fast on high? You betya. Is it fun? Hell ya brotha! A 219b at 4 amps runs just great, but I would aim for 3 amps in anything really small personally. The gain from 3-4 is negligable and creates lots of heat. A T2 or T3 size host will work just fine for a 219b at 3amps, just don’t expect long runtimes at high due to heat.

Nice! How long can you get away with running that thing on high? Is that a FET driver or regulated? This looks like it could be a great option with the right battery & driver. Do you know what size driver the T3 takes?

High is not a sustainable output…

T2 does 464 lumens at 30 seconds


Not with stock AA/14500 driver. But what about Convoy 12group driver(17mm)?

the issue is thermal mass, not the driver

the T2 is a 50 gram host… it cannot possibly sustain its maximum output

otoh the Convoy L2 has over 10 times the mass… which allows it to sustain its high output:
runtime and reviews thanks to zeroair

It’s a regulated driver. On high I can run it for around 20-30 seconds before it gets uncomfortably hot, then temp regulation kicks in and it ramps down. It’s a glorious amount of light for that short time though!

not sustainable…

about how many lumens do you think the T2 can sustain, flat regulated like the chart of the L2, without stepping down or overheating?

my guess is the thermally sustainable level for the T2 is about 120 lumens… based on this chart thanks to zeroair

Thank you for this. It sounds like the kind of thing I’m looking for, and it may last a little longer with only 3A running through it. Or maybe I should just make the same as you with one of the 519a emitters I’ve got coming in the post!

I think it’s a little hard to tell from that graph because the T2 was cooled during the test. However the temperature only ever reaches around 26C and the temperature curve is flat around 10 mins in when it is producing 160 lumens, which is the thermal equilibrium for those settings. It’s hard to say what the maximum usable output could be from this host, I imagine it would be a bit higher than 160 lumens if you allowed the host to reach 40C instead (a conservative estimate for pain threshold).