How about a SL 4AA 7 LED Run-Time Plot

LightScene · Mar 30, 2004

The SL 4AA 7 LED is one of the most recommended flashlights on CPF. We should have a run-time plot to see if these recommendations are based on fact or fiction. I guess you know what I think.

Doug S · Mar 30, 2004

It exists. Not done by runtime guru Roy. A search of old posts should find it if you are patient. The board search function leaves much to be desired As I recall it stays at a high level of 5 to 6 hours and then drops sharply. The plot was for the Rev 0 of the light that used individual 12 ohm resistors for each LED. Resistor values have since been increased.

LightScene · Mar 30, 2004

I've looked for it in vain myself, although I do recall seeing one. What I remember was a severe drop-off in the first hour, followed by a continuous decline.

At any rate, we need an official run-time plot for this light. It is easily one of the favorite lights in CPF, and it gets recommended as much or more than any other light.

Roy · Mar 30, 2004

Wellllll.......if someone would loan me a SL 4AA 7LED I'd be more than happy to do a runtime plot! /ubbthreads/images/graemlins/naughty.gif /ubbthreads/images/graemlins/grinser2.gif

Doug S · Mar 30, 2004

[ QUOTE ]
LightScene said:
I've looked for it in vain myself, although I do recall seeing one. What I remember was a severe drop-off in the first hour, followed by a continuous decline.

At any rate, we need an official run-time plot for this light. It is easily one of the favorite lights in CPF, and it gets recommended as much or more than any other light.

[/ QUOTE ]

Here it is: Runtime

The peculiar shape of the output curve for an unregulated light is due to the LEDs being grossly overdriven. For the first half of the discharge the current is so high that the resulting high temperature reduces light output. After the battery is considerably discharged and current reduced, the temperature drops enough to permit higher output. The excessive current in the first half of the discharge serves only to degrade the LEDs.

LightScene · Mar 31, 2004

Thanks for that run-time link.
It looks like it takes 5 hours to reach 50% of maximum brightness.
But it drops from 130 to 80 in about 15 minutes, then it briefly rises back to 100. Beam shots of this light are misleading, because they are always taken with fresh batteries. Basically, this light runs at an average of about 90 candelas for 5 hours.
It costs about 25 cents an hour to run it. It's a shame it doesn't work well with rechargeables. For most people, that would really improve the overall brightness.