Most efficient flashlight ??? (AA & or 18650)

I was just thinking, is there anywhere or anyone that has done a comparison or list if lights that utilize their battery power to light output ratio the best?
Thinking along the lines of SHTF/grid down for extended time. I keep a large set (dozen or so) of cheaper lower capacity 18650's i got a while back ready and charged, as well as a good stash of AA's.

But what lights out there would be best for getting good usable light (not moonlight but something in the range of 20 lumens on the low end up to maybe 50-100 at most on the high end) and the most runtime. Obviously reliability would be of concern too, if it doesn't work when you need it its no good, but lets keep it more budget friendly for the most part Any suggestions? Like the title says probably a light in each catagory would be good.


By the way ive been a member here and lurked a really long time, i enjoy reading through everyones ideas and opinions an reviews here just not a lot of time to interact.

The Malkoff M61LL ('low-low') P60 dropin (or LLL/LLLL - which are rare/semi-custom) is an excellent candidate.
Lumens are what, ~80? And 18650 runtimes are epic.
Gene M designed this module to maximize efficiency, and durability is the traditional Malkoff hallmark.

For emergency situations, this module as the advantage for running virtually forever on 2xAA Alkalines (not NiMH) in a 3xCR123 body, providing gradually-declining outputs in the 10 lumen range.

An "inefficient" 10L light will have longer runtime than an efficient 50L light, so your best bet is simply to get a multi-mode light that you like and use it at the lowest level that meets your current need.

My Fenix e12 claims to get 40 hours at 8L on NiMh (22 hours on alkaline) which seems like plenty of light for a SHTF situation. Unless you're outside searching in the dark, any light brighter than, say, 60L is overkill for most blackout activities.

There used to be a whole bunch of "sublumen runtime fanatics" here on CPF ... but I think @reppans is the only one still left.

He ran lots of efficiency tests on various flashlights, but not anything anywhere near twenty(!) lumens. More like 0.01 to 1 lumen.

If you use the search tools for his posts, and other similar topics, there is a lot of (mostly old, but still valuable) info around.

Also (and probably obvious), but for real situations of the sort you allude to above, 20 lumens is a massive amount of output for many or most purposes.

yeah that's why I kinda mentioned 20 lumens as a starting point. more than enough for Indoors, and still decent even outside, u less you need to see across a field. just curious if there were known lights to just be really efficient. I have numerous multi mode lights so in reality I'll just use those on the lowest level needed for the situation to conserve power. the drop in mentioned above is interesting.

If you like the idea of a predictable, ultra-reliable light, it's hard to beat the Malkoff dropins. I have a M61WLL (warm, low-low (60 Lumens)) in a polymer NexTorch host which runs forever on a decent 18650. I also have a M61LL-219B (hi-cri emitter, low-low (50 Lumens)) in a Surefire G2 which, in theory, should be utterly bomb proof, but I discovered that the spring was etching the bottom of my 16650 cell so I replaced the larger cell with a 16340 + metal spacer.

But the one that gets the most use is a M31LL-219B (hi-cri emitter, low-low (50 Lumens), 3 volt input). I have it in a VME head on a Lumens Factory E1 body and I was going to feed it all my old CR123A cells, but after a year's use I'm still on the first cell.

Based on the runtimes I get with the LL models, I can only imagine the epic runtimes the LLL models must get...

Zebralight sc64w has a 22 lumen mode that's supposed to last 2.8 days. Depending on the led, they may have more efficient models.
Zebralight sc5 also has a 20-30 lumen mode and claims 22 hours.
im sure there are runtime tests somewhere.
The sofrin c01 is a lot like the Fenix eo1, ten lumens 1aaa and a great keychain option

Re: Most efficient flashlight ??? (AA & or 18650)

For reference, and as I get time, I'll try to link up some relevant threads for your topic ...

http://www.candlepowerforums.com/vb...-cool-beasts&p=4703187&viewfull=1#post4703187

http://candlepowerforums.com/vb/sho...licky-140-200-amp-N170-Low-Mode-Runtime-Tests

http://www.candlepowerforums.com/vb/showthread.php?317810-Logan-QTC-Runtime-test...-DONE

http://www.candlepowerforums.com/vb...K-hr-Update*-L1-RD-(L1-Red)-vs-X5-Red-vs-24-7

Re: Most efficient flashlight ??? (AA & or 18650)

In general, the higher the voltage you start with, the more efficient the light is likely to be. Higher voltage means lower current, and the losses are proportional to I^2 x R, so doubling the voltage cuts the current in half, but reduces these loses by 75%. In addition most semiconductor devices have 'overhead', generally in the .5 to .7 volt range. The higher the voltage, the smaller the portion of total energy these losses take up. So all other things being equal, a pair of AA's is simply no match for a single 18650. At best the pair of AA's is going to be good for no more than watt hours, while most quality 18650's are good for at least 10 watt hours. There just isn't any way for a pair of AA's to compete with a single 18650. The higher voltage already gives the 18650 a significant advantage, and the actual energy content of the 18650 is substantially higher to begin with.