Longest running AA flashlight?

What's the longest running AA flashlight out there? Say in lumens per hour. Or hours per amp.

Ok, I’ll throw out what I think best answers the question.

The ZebraLight SC5 which apparently can go for 4 months on firefly mode (0.1 lumens) with an eneloop pro AA battery.

Light Output (runtimes) (according to ZebraLight)

  • High: H1 535 Lm (3min, then 325lm, total 0.8 hr) or H2 325 Lm (0.9 hr) / 200 Lm (1.8 hrs) / 115 Lm (3.5 hrs)
  • Medium: M1 48 Lm (8.5 hrs) or M2 20 Lm (16.5 hrs) / 8 Lm (42 hrs)
  • Low: L1 3.2 Lm (4 days) or L2 1.1 Lm (16 days) / 0.3 Lm (50 days) / 0.1 Lm (4 months)

A better way to look at it is “What AA light draws the least current on LO mode?” That will be your best answer, barring measurement inaccuracies, production variation and other random factors.

I think kramer 5150 has it right, but depends what you're getting at. Of course with a tiny enough LED output and low drain electronics you can run for probably months off an AA. You won't be able see past your nose with it though.

But if you're interested in best runtime at any particular brightness (lumen hours, not lumens/hour) then the right question is maybe what's the most efficient flashlight. I guess you want a cool white LED and a good buck or boost driver, but we're not talking about giant gains here, if you even consider the higher lumens of a cool white to be a gain at all (I don't). As far as amp hours (amps per hour doesn't make sense) that's just a matter of battery capacity. I think the "heavy duty" low capacity ones are actually supposed to last the longest at low drain though.

What’s the longest running AA flashlight out there? Say in lumens per hour. Or hours per amp.

Based on lumens per hour, there will have to be a targeted lumen output specified. It wouldn’t really be an effective way to evaluate them though because you’d be limited to those with that specific lumen output mode.

Evaluating a light based on hours per amp (assuming you mean a 1A tailcap draw for each candidate) won’t tell you which light runs longest because they will all run the same time since they all draw that same 1A current. It wouldn’t really be an effective way to evaluate them though because you’d be limited to those with that specific tailcap draw as one of their output modes.

I am presently testing the run time of my Thrunite Archer 1A v3, which boasts 17 days with a 0.1 lumen output. Based on this manufacturers advertising data, I find it highly unlikely you could get the same 0.1 lumen out of a different AA light. I suspect either there is a typo in the data sheet or they are just lying.

I got 200 hours out of a AAA cell in my Manker E01, but toward the end the light output was no longer 0.1 lumens. Based on comparing my Manker and Thrunite, which both boast 0.1 lumen output modes, the light output toward the end of the 200 hours run was likely 0.01 to 0.03 lumen. The manker does not regulate the current, while my Thurnite does.

The run I am presently doing with the Thrunite is with a battery that has a best used by date of 2003, so I don’t expect big things in terms of run time. The current being drawn with a 1.4V battery is 5.35A or so. Using 5.5mA, in 17 days you would need 2244mA*hr capacity. I am thinking AA alkalines are closer to 3000mA*hr, so I beleive with a new battery the light would likely last at least 17 days. Looked at a duracell AA data sheet and it shows for a 5mA current the battery can last a bit over 500 hours and have a voltage of 1.1V. For 1.2V it is more like 450 hours, which is pretty close to 19 days.

Once I see how long the 20 year old battery lasts at this level I will try a newer one.

BTW, 0.1 lumen is very usable in a dark inside environment, like walking through your house in the middle of the night.

If you want to use it for emergency candle you need to define the lumens

It makes no sense the light runs from 0.1lumens down to 0.01 lumens fow weeks very efficient, but none of the modes of the light have the lumens you want

In the range of 1-5 lumens the differences are not so big between runtimes of the lights

The ANSI runtimes say till the light drops below 10% of the modes brightness, so a light that drops early down will run longer, while a light that keeps the modes full brightness till the end loose in runtime, even if its as efficient as the other

At these super low modes, most of it is likely down to the chip, and how well the power save modes on it are programmed. The lowest I've gotten an attiny25 to run with PWM on is 2.1mA, which is I guess is more than the LED current draw at 0.1 lumens. 2mA is still low enough to last for over a month with an 18650 though.

L11c w Nichia spec is 147 hours (6 days) @ 0.09 lumens

SC5 spec is 2880 hours @ 0.01,

SC5 claims to last almost 20 times longer, but no Nichia, yesPWM, and is 9x less bright (useless to me)

Just as a reference point my Archer draws between 4.5 and 8mA at battery voltage of 1.5 to 1.1V. This is the 20 year old alkaline referenced above. I have gotten about 2600 mA-hrs out of this relic at these low currents. 17 days of running thus far, but it is definitely on its last leg, as the battery is at 0.96V. I know the battery can keep giving, but pretty soon the undervoltage lockout of the light will kick in and it will shut off.