which flashlight brands have the most efficient drivers?

Over on Reddit, I made an observation to Zak (he posts as zak.wilson here) about the efficiency of an Acebeam he reviewed, and he countered by pointing out some of the more efficient lights he had tested were much better than the one we were discussing at the moment (based on an approximate calibration method, I believe):

These were just from high CRI lights that he reviewed. He’s tested a couple low CRI Thrunites and Olights that were in the ballpark of 200 lm/W.

Thanks, added. Zak is a good source. I might go through his older reviews, he did some good tests on the Thrunites iirc.

For now Convoy have most cost - efficiency optimized boost drivers - flashlights.

Lumen per watt is a bad measure of efficiency as it’s mostly dependent on the emitter which is used. Also, it depends on what current the emitter is driven at. An underdriven flashlight will be more “efficient” everything equal.

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I’m trying to hunt down runtime graphs. That’s more helpful to me. I’ll leave the lmw for now.

I made a topic here with efficiency measurements of some drivers : Efficiency measurements of a few drivers

Unfortunately I don’t have that many flashlights especially from majors brands like Acebeam, Olight, Fenix, Thrunite… etc to compare them.

Zebralight gets often parroted as ”very efficient” but that depends on the model, the SC64 (XHP35) is not that good, and the H/SC53 is very bad (it’s an AA light though, it’s bound to be less efficient), the SC700 is excellent.
I have a H600II and a H600 IV opened so I’ll try to measure those too.

The Skilhunt H04/H03 is often recommended as a higher value headlamp compared to stuff from Sofirn for example, thanks to it’s buck driver, but while it’s better than FET direct drive and to a lesser extent linear driver, its efficiency is not good for a buck driver.

The Convoy XHP35 driver has been measured here : Convoy XHP35 Driver Analysis / Testing / Schematic
(Modified to 6V and RPP FET bypassed so slightly better numbers than stock). And it’s very good, most of their switching driver looks to be using good synchronous converters and good components (low RDson RPP FET, decently sized inductor) so it looks to me that their offering are pretty good.

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H04 as a asynchronous buck driver have good efficiency.

how about nitecore e4k and emisar d4v2?

Only synchronous buck or boost drivers have highest efficiency. But its technical data and ordinary potato user dont care about it, so manufacturers advertising lumens only.

EK4 uses a buck driver (edit : or boost maybe if the LEDs are wired in 4S), given the high power I think we would expect good efficiency at sustained output level, but ultimately we can’t really know without measuring or at least seeing what the driver looks like.

D4V2 uses a linear driver (not sure if they still use the older FET+7135 at all), sustained output driver efficiency is going to be around 75% in average.

how about SC5w Mk II AA Flashlight Neutral White? ps ty for all the input my fav light feature are small size for battery and efencecy

I’d say among the best for AA lights, probably above 85% max efficiency, and above 70% at max output.
The boost converter used is the LTC3425.

cool ty it will now be my edc.i also love batterys for it are sold at every store in the world

It’s hard to measure efficiency with a single metric, but from a driver standpoint, boost/buck are most efficient with everything else (FET, 7135, or equivalent) less so. It also depends on the emitter. High CRI low CCT are less efficient, and also depends on how it’s driven (direct vs. refulated). So far, lights with xhp70.2 behind boost or buck drivers have been most efficient in my experience. I’ve had good results with XPG3, and XP-L2 as well. Cyansky, Skilhunt, Thrunite, Acebeam, and Convoys newer ully regulated boost/buck drivers are all very very good. I haven’t tested it personally but the Lume1 driver in the fireflies E07x is superb (but spendy)

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You can have a 6000lb SUV with a V8 thats efficient.

Most high MPG cars are small. If I have to give up size to gain in MPG , that does not make it efficient. I paid for greater mpg by giving up size.

With electronics, efficency has to do with how much energy is lost to heat. So if you have a 1000lm light that gives 1hr run time compared to a 1000lm light that gives 45 min runtime but runs much hotter, that light would be less efficient.

If you compare a 1000lm light that runs for an hour vs a 2000lm light that runs for 2 hrs, you really dont kbow which one if more or less efficient.

if I have a 2000 lumen light and only use 1000 lumens, that will double my runtime efficiency :wink:

an AA light cant reach 1000 lumens at all, it has zero efficiency, for that lumen level.

similarly with cars, MPG efficiency changes depending on how fast you need to go, or how heavy a load you need to move

jon me and most humans dont speak the same langauge lol. i want as much lumens per watt. i use low lumens most the time under 2 lumens.

if lumens per watt efficiency is what you want

ignore me and anyone who tries to talk about runtime efficiency, Lumens, and battery size… lol

Im glad you found your Zebra AA suits your needs and wants

enjoy it :slight_smile:

I like topics threads that have high knowledge shared efficiency. Like this one. This is a very high knowledge sharing efficiency thread. But there is room for other types of topic threads, for example, the recurrent topic that reminds me to wash my dirty laundry.

Well, anyway, I have seen the names of many various manufacturers mentioned for good, efficient drivers. I certainly don't know of any makers that are known for horrible drivers.

Efficiency has a ton of variables. A driver might be efficient at high outputs but not low - or vice versa. Also, you can have efficient drivers with inefficient LEDs, or the other way around, etc…

A FET driver at full blast is the most efficient driver there is! Too bad the led is far from its efficient operating zone, though.

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