Foursevens has a new light that sports a whopping 840hr @ 1 lumen, max run time on one 18650. Not sure what battery they test this with. Either way, seems pretty darn long time to have “some” light available. Does anyone know of a longer one? Guess there are so many variables in this.
Exactly 35 days of runtime exactly.
I remember I ordered a Palights (even more expensive than a SK68…) and the low off mode was said to last 2 years. In fact it’s never off, the off position is in fact a moon or firefly mode. But it never last 2 years with a copper top duracell, maybe they tested with a primary lithium.
I have only one flashlight with a moon mode and it’s my EDC so I won’t test now, maybe other tested they moon mode over the time.
A fine example of exaggeration at its best :bigsmile:
The spare cell linked to on the that page is 2600mah, its advertised as that light’s spare cell and is the only 18650 they sell so its safe to assume thats the one “tested”.
Shortest runtime = 2hrs at 800lm :- an XM-L2 (assuming T6) pulls at least 2100mA to get 800lm, by my math that would be 4200mah needed.
EDIT, as pointed out rather bluntly by Omega_17, my statement below is wrong by not allowing for PWM.
Longest runtime = 840hrs at 1 lm, just a pity that the XM-L2 needs 150mA to fire up and that gives 72.9lm (Cree data) so no 1 lumin, 2600 divided by 150 = 17.33hrs, even if you allow a couple more hours due to getting the max out of the cell because of low current, that is a looong way from 840hrs
Cree do not have a power led that gives 1 lumin, in theory if you scale down the XM-L2 to 1 lumin it would draw 2mA, that would work out to 1300hrs
I have one flashlight with XM-L2 and firefly/moon mode and it’s not 72.9 lumens, there is a minimum mA to be applied of course.
A lumens is defenitively not 2mA because the light output is not linear, it’s logarithmic. I too was bad in math but that mean for example for 1A you have 400 lumens, at 3A you have 800 lumens, you applied 3 time the intesity but it’s not 3 time brighter.
Completely forgot about PWM, I was working with constant current, thats my excuse and I am sticking to it
Still right about the shortest run time though
I would have to say, It is very impressive. I had one that I hooked up to a old 9volt I had laying around. I put it on and left it for several days, and noticed no drop in output. Not scientific, but real world. I want to say I paid like $30 for it way back when they first came out. I lost it a few years back when I moved houses. I want the glow model now.
It was built like a tank. Felt solid. If you need transport a 9 volt (which I have to do in my vehicle) it makes a great “safety cap” too.
Is it worth the $25 or so bucks? Well that is up to the individual, if you were crafty with some tools, I am sure it would be easy to make one equal to or better than. I have seen a few built on some websites. Just google 9 volt LED for ideas. But, I am not handy with tools. And my spare time is so limited between keep up the bills, work & family (not in that order) :bigsmile: . So, I have to buy stuff.
Its not super bright, but thats not the idea. I would classify it as a back up reading light.
I once soldered a trustfire cr123 to a white led, very ugly but funny too.
still lightning after 3month…the lower the battery voltage gets the lower the current is so this is self extending…in the totally dark this even the smallest led is enlighting the whole room…
The led was from a ballon with a led and some coin cells to make it glow for a party.
I recycled the old led and the battery I had laying around to build a huge 16” lighted helium balloon as a gift.
At 3Volt there were 2mA flowing…and I switched it on 29th September…I got the empty balloon back on mid December and was impressed by myself to that it was still lighting after removing the shrinked balloon.
Koda, “The compact light was designed to run approximately 1,200 hours on the low setting, but the manufacturer reports that some units are still running over one year and 8,760+ hours later. Priced from $24.” excerpt from a review on their website.
Thats the one I am gonna order to replace mine. I had the original. It didn’t glow. I have something for stuff that glows! lol
I have first generation Predator. Never done the 100 day test it claimed but even in this firefly, get-you-home mode, the beam is useful with dark adapted eyes.
I understand that Armtek use a separate backup circuit in this mode.
Also don’t forget that all protected batteries use very small current draw for the protection board all the time, maybe the same amount as a low power LED. The power consumption is maybe even lower than the normal battery power loss over time. And I bet half of the energy is lost in the driver.
The runtime is indeed spectacular ! Even at 1 lumen its very useful for night-walking indoor with virtual unlimited runtime.
I did not realized protection boards have a current draw. This explains why my protected batteries self discharge around 0.1volts every 5-6 days. I always attributed this to low quality construction and battery self discharge.
