Seeking advice on most efficient moderate lumen optics, driver, led (FT03 or some C8/M21?)

Right! Though big dies are more efficient in lm/watt they are not necessarily most efficient in “usefull.beam/lm/watt”. Indeed, effictiveness may be a better word here. :slight_smile: I have not enough nightbiking experience but I would guess: say, a gravel road of ca. 4 meter width at a distance of ca. 100 meter. I think a throw par excellence osram led would be too narrow, though. Or not? A bit of low light spill in frónt of the bike and perhaps some on the side (without harming night vision) would be desirable.

This tube light impresses me with it’s Osram P9 emitter and buck driver. The beam is throwy yet wide enough to be useful. 2.5 hours of 400 lumens.

For my gravel trail / XC rides, and work commutes I have been using a fenix E35UE for a few years. It’s an older light, less efficient by todays standards but it has proven to be reliable and will maintain about 350~400 OTF constant ON. Nice floody multi-purpose beam, that throws far enough for my needs. Since my top speeds are only around ~10-15 mph. I dont need to see way out. I just need to be careful of squirrel, rabbits and wildlife that can dart out onto the trails.

I always carry a couple spare 18650 cells in my pack, and a SF6P as backup. The last thing I want is to be stuck somewhere with no way to light up the trail

Thanks for the imput. Yes, I would need to see some distance to anticipate problems at my speed. That Wuben seems to have very short runtimes in comparion with e.g. the Lumintop B01 which has nearly 5 hous at over 450 lumens if run on a 4Ah battery, but has modest throw of 200m (how much of this is useful though?).

You need to figure out your stopping distance at top speed to estimate illumination throw distance. Stopping distance varies significantly from rider to rider over various declines and terrain types. Your illumination reach needs to out throw this distance, so you can spot hazards with enough distance to come to a stop before hitting them. You never want your stop distance to exceed the range of your visibility (in general… day and night).

The safest answer to this, without knowing your actual stop distance is “the more lux and lumens the better”. Better to have and not need than to need and not have. Of course theres a trade-off penalty to this philosophy, cost, size, weight…etc.

I am not familiar with that Lumintop B01. Looks like a nice setup for starters. It has a unique looking reflector, designed not to blind oncoming traffic. Not sure how useful this would be on the trails though. In the spirit of your original post requesting efficiency, I am not sure how it blocks light from oncoming traffic. Does it simply obstruct (entrap) that light? or does it reflect/re-direct it OTF? The former would be less desired for lumens/watt efficiency. I personally prefer a traditional reflector, and I just aim it down to the ground a little.

Rattlesnakes are also a common trail hazard in my area. They come out at night to hunt nocturnal rodents and sun themselves on the trails during the day.

The Wuben comes with a rather low capacity 18650 (2600). The Lumintop is probably using a 5000 mah 21700 for run time estimates.

The Wuben comes with a rather low capacity 18650 (2600). The Lumintop is probably using a 5000 mah 21700 for run time estimates.

Dont forget bike mounting too (!!).
The handlebar mount I show in my pic is only good for smooth trails, slow speeds and urban commuting. So its OK for me but I would not recommend it openly.
A better / safer recommendation is something like this one here:
https://www.amazon.com/gp/product/B088WH6HBM?pf_rd_r=JT3ZP84D6DECH5D91Q9X&pf_rd_p=5ae2c7f8-e0c6-4f35-9071-dc3240e894a8&pd_rd_r=ec884ccd-b468-4dcf-a87b-5fbbb2af4f8f&pd_rd_w=38p8K&pd_rd_wg=YIJnB&ref\_=pd_gw_unk

A heavier / bigger light like a 21700 with onboard USB charging will require a more robust mount (all else being equal). For me personally I prefer a small / compact light on my bars, and I just bring extra 18650 battery or two in my pack along with my trail tools, spare tire tube, patch kit…etc. Since I’m generally not in a hurry when I am on my bike, its no biggie to stop and swap cells. But this feeds back into my overall preference to keep the bike as light & nimble as possible. Any added weight from my tools, lighting and hydration is in my pack… not mounted to the bike.

I didn’t see it mentioned yet but you should also confirm PWM. On an active use trail/road light you don’t want any PWM at any mode. I would consider this a deal breaker for a bike light.

No with 4Ah as I had calculated in the post above. The tests of were done with 2.6Ah battery running 2hours30 at 467 lumens so that is not very dissimilar indeed. :slight_smile:

- Right about stopping distance. It would also vary with the incline and the state of my breaks. A speed of 28km/h recalculates seven meters per seconde so that an effective throw of 100 meter should give me a decent 15 seconds of anticipation time.

- That mount you link to was the one I had decided on. They go for cheap on aliexpress.

  • PWM, I would like to avoid too. Mostly an issue on direct drivers, no (e.g. FET +1 should have no PWM for the lumens that use the linear driver but those lower lumens that go beyond that driver would have PWM?)

I though I would just have to live with the nuisance of lights from oncoming trafic and can’t imagine how a reflector could catch it (though I could imagine a light on high or turbo being on the same level and hence reducing the hindrance though depleting the battery). Could you explain this a little further?

Lumintop B01 has a horizontal projection and the lumens cannot be compared to those of round spot lamps

If you want a LED that is efficient while offering some throw, something domeless with large die will be better than a domed LED.
See this 2-years old compilation to learn more:

BTW, I thought that it would be nice to update this chart with newer data….and I can’t.
Koef3 is not here nowadays.
djozz has mostly ceased testing.
Texas Ace has ceased testing.
maukka? No LED review from him in almost a year (though I think he’s done some quick tests since then).

There are some new people filling the gap but not many of them and doing mostly quick tests rather than full fledged reviews.

While more light and throw is always better, back when me and my buddies were hitting singletrack at night, it was amazing how effectively you could see with diminishing output as the eyes adjusted. For example, a 100 lumen helmet mounted light was quite adequate in the dark. Now, if you are competing against street lights, shadows, cars, etc it will feel different. But in the dark on the singletrack it was surprising. Now, I usually rode with more than that (a triple SSC P4 on the handlebars as well) which was amazing.

Don’t focus solely on throw, either. A pencil beam is going to give you an uncomfortable, tunnel vision experience. I really liked the triple SSC P4 because it offered wonderful spill. Worked amazing with a semi-throwy helmet light. Whatever you do, don’t stick a lone thrower on your bars and expect a good experience. Something like my Convoy S2+ SST-20 with OP reflector gives and excellent helmet light beam. If you did the 7135x3 driver, 35% mode gives and estimated 126lm for 8+hrs.

Here is a chart I built with the help of BLF member tests. The lumens are generally estimated and the runtimes are calculated. And altough I forget what mAh I used for the calc, simple math can tell you that :wink:

I would use a head lamp and a single cell light handlebar mounted, that’s what I do on my Xc bike. I do a KR4 on the handlebar mount with the Olight handlebar mount (nice piece for about $12) and a sofirn sp40 headlamp. Both can maintain around 400 lumens (guestimate) for a while (over a couple hours) if you don’t put them on turbo/blast mode for more then a couple seconds here and there.

Here is an interesting discussion regarding efficiency of linear drivers: Led4power.com : LD-4 CC linear drivers, ILC-0/1 illuminated tailcaps, optics, MOSX, copper DTP MCPCBs... - #6 by led4power

Thanks for that link! If I understand and ’gestimate” the graph correctly, the non-dedomed SST40 trups all others in the graph up to ca. 350 lm. And from there up to 530 lm it trumps the dedomed SST40 (but not the XHP35).

If that is correct then the non-dedomed SST40 may actually be one of the better choices among existing leds for my purpose, a usage btw. say 100 to 400 lm? (P.S. I would be to worried to try dedoming a led)

That quote was also useful for calculating efficiency of a linear driver. If I apply the formula for user case the efficiency is less great. If I usually ran a SST40 @ 250lm it would itself use ca. 2.75V. (see Luminus SST-40, a N4 BA bin tested)
Using the formula, I get an efficiency of 1/2 * (2,75/4,2 + 2,75/2,9 [if I use the battery slightly below 3v]) = 80%.
I read somewhere that the efficiency of switching drivers runs between 75-85% but also that Simon Mao claimed 95% for his 8A buck driver. Perhaps I should hold off until an equivalent 4A driver for C8+ shhould trickle down. Could that happen?

What I really would like to know now, is how Simon’s C8+ SST40 driver —also with an 8A mode (and 1.5A mode; said to be a regulated FET driver)— compares with that of say a regular M21A or a C8G?

Efficiency depends vf led values. Sst40 vf at 300 lumen is 2.7v…….so 2.7/4.1= 66% efficiency.
At 1.200 lm, vf 3v, 3/4= 75% efficiency

Like someone mentioned above, Not so sure I would go with a thrower on the bars. I liked a flood light when I was riding. I was also a slow rider at night, so my needs were different.

I would lean to any quad light and 26650/21700battery to run it as it is going on the bars and not on your helm to add to possible neck strain.

Again my needs most likely do not match yours. As I was riding in a large combination of night environments from on the side of the well lit roads, to mile long stretches of single tracks through parks and bike paths that were unlit.

I am thinking rather than the FT03 You may like the FT02S as a better choice, More spill and 200-300 yards of useable light. This has been my go to this year as I am out in the dark more than the last few years here up north.

S2+ sst40 and w1, S21A sst40, EC01 sst40 and xhp50.2, FW21 Pro and X9L, M21A sst40. This are the ones I have used,
I find more than EC01 too big for me