So interesting points for this test are mostly in the ultra low Vf, by far the lowest Vf I have tested so far! So this is a very efficient LED when driven reasonably. For us that also means no FET driver for us, at least without PWM regulation. This thing would pull some serious amps on turbo!
It also worked surprisingly well even at the higher power levels. It beat out the 219C D320 all the way up to 4.5A before the lack of a thermal pad and DTP caught up to it. Way better then I had figured it would do. The Vf difference is amazing.
I tested it all the way up to 11A as you can see in the chart data but only put the first 7A in the graph. It just kept nosediving after that. at 11A the dome started to audibly crack so I called it quits. It is one tough LED.
Overall it is a far better option then I would have guessed at first glance. Makes me curious what the E21A can do with a good mcpcb since it has a thermal resistance of 0.3c/w vs the 229’s 2.3c/w.
I am not sure what that quote means in this case? The LED is still alive right now and PWM was never used in this test. In fact I would guess it would work perfectly fine with PWM, just with a loss in efficiency as expected. Although in my testing even a 50% duty only drops efficiency by less then 13%.
Although none of this has anything to do with this test near as I can tell?
Ok, I have the test 229AT on the bench right now running off a full 4.20V from my power supply with an A6 driver on mode 4 or 5 for a final output of 1.32A @ 4.20v.
It has been running for the last 5 minutes or so just fine, no issues at all. Although the driver keeps coming loose and making it turn off.
It is using the stock wires from the A6 driver to power it and is basically how it would work in the real world. As long as the total current is kept to a safe level it should work perfectly fine.
I keep wanting to get a function generator and/or a variable duty setup to allow me to properly sweep through the PWM range both in duty and frequency., right now the best I have is using a flashlight driver with a PWM mode.
I also tried the higher modes as well and had no issues until like mode 6 where the current was trying to go above the 7A I had my power supply limited to. The LED was still fine though obviously.
I also tried it hooked up to my charging setup with 4 cells powering it, same result, although the voltage sag caused it to actually be an easier test since it was only getting around 4.1V input vs the 4.2V from the power supply.
I think I can safely say that if the PWM is managed properly and total current kept in check, this LED will indeed work just fine with PWM. Although the efficiency will suffer some obviously.
So yes, I still stand behind the above quote, PWM is not ideal but it is the only viable option for high current, low cost and compact flashlight drivers unless something new come on the market. Remote mounting an FET is a better option but not something we can do just yet and comes with it’s own issues.
Hmm, I should put it on the sphere with the PWM to see how it compares, although I don’t know what the duty cycle is on the A6 driver.
Yes, it would work great for these lights. They don’t produce nearly enough heat to cause issues and the low Vf would help them a lot. Same goes for lights with buck drivers, it would stay in regulation longer.
We dont know led electric properties (such as Xl and Xc) so Im not 100% sure about same current peaks in pwm and in full throttle.
Anyway, mine idea was that full throttle current can burn led internals (thin wires, diode and etc). I expect 11-12Amps from good build. Your 4x18650 carrier seems to have bad springs and thin wires.
If I ran it at 100% duty it would have easily gone WELL over 12A, this is why I stopped going up in modes after mode 5, I went to mode 6 briefly and current spiked to over 8A. The LED survived just fine but I knew that was too high.
If you run it at 100% duty then it is not being PWM controlled and thus any discussion of PWM is moot.
When PWM is controlling the current then things work fine, just not as efficient as it would with constant current.
By staying in mode 5 the PWM duty was around 20% and this limited the current to around 1.3A. Which ran without an issue for over 5 minutes.
As far as the carrier, it was perfectly good but doesn’t matter. The power supply was outputting a full 4.2V, more then any battery will output as they will all sag at least some. So the power supply is the hardest possible situation that the LED could see for an input voltage.
The output side was using the stock wires on the A6 driver as I said before, they are 22AWG? not super thick but plenty thick enough, it would be silly to use super thick wires with this LED, personally I would use long 26 or 28awg wires if I built a light with this LED (unless it had a buck or boost driver).
Correct, average current is what I am using. I don’t have a scope good enough to see the peak current but I am sure it is indeed over 10A. That is fine though, the LED doesn’t die at that point, I simply stopped going higher.