High amp driver efficiency at lower modes question

Flashlight Modding and DIY Parts
1

I have a Convoy S3 triple nichia 219 build on order from mountain electronics. I decided to go with the highest (5.8A) amp driver he offers. My question is will the efficiency of the lower modes be reduced vs a lower 4.4A driver. For example, everything else being equal, If I had a 5.8A and a 4.4A flashlight left on moonlight mode and the 4.4A driver lasts a month, how long would the 5.8A version last? My thought is 5.8A is about 32% more amps than 4.4, so the light output at all levels will be 32% more lumens and 32% lower runtime. I’m guessing if the 4.4A driver last a month, then the the 5.8A driver would last about 20 days. Does that sound about right? I’m asking because I understand on high mode it takes a lot more amps to get a little more lumens, so efficiency drops off and there is diminishing returns. I’m hoping that loss of efficiency doesn’t effect the lower modes.

2

Yes, lower modes are less efficient also for drivers using PWM because the LED is driven at full current, just 'blinked' with a lower duty cycle.

3

Going for 5.8A is because you want the best output on the high setting. Because the lower modes are made by PWM, the efficiency suffers from choosing the high current on high. But in a triple the efficiency is still not bad at all, each 219B receives 1.9A, that is low enough for not being worryingly inefficient. I.E. a single XM-L at 5.8A is a lot less efficient.

4

Thanks for clearing up my confusion guys. Thats what I feared. That the lower efficiency is across all modes because even in moonlight mode the leds are being driven at 1.9A each. Too bad there isn’t a variable amp driver that overdrives only on turbo and uses really low amps on lower modes. Doesn’t sound like the efficiency drop is that bad though.

5

Thanks djozz for easing my worries. I just read your post you did back in January with the nice graphs testing the newer nichia 219b’s. Based on those graphs it looks like the newer 219b can handle 1.9A with no problems.

6

Please do a review or give some feedback when you get it, I’m particularly interested If it will melt, because my s3 gets pretty hot when driving a single xml2 at 2.8A

7

Not sure what driver is in those, but if the driver uses a "dual PWM" design, the moon mode efficiency could be identical. In a dual mode driver the moon mode is handled independently by a 7135 chip and not the big power FET circuit. Moon mode (typically about 1 lumen) is quite difficult to achieve with single PWM.

If it is a single PWM then all the above posts apply.

Hope this helps.