Talking with someone on a different forum about the new Maglite 3D LED he just ordered. He stated that its 130 lumen and has an 80 hour run time. I thought that was outstanding so I went to ML’s website and sure enough, they have it listed as 131 lumen with 79 hours of run time.
Among the other flashlights I have, I really like Maglite products. Nostalgia on my part perhaps being in my line of work and even going back to the military before that. As it is, and I’ve spoken about this in other threads here, I took my old incandescent ML’s and replaced the bulb with the 55 lumen Niteize drop in. This was for a couple of 3D cells, a 3 C cell and a 2 C cell.
I don’t know if this question can be answered specifically or not, perhaps a ball park answer but I’m curious if a ML (3D cell)that puts out 131 lumen can have a run time of 79 hours what to you suppose a 55 lumen LED may have in run time?
It depends on how much current each one is using, which you can't tell anything about just from the lumen output since they almost certainly use different drivers and LEDs.
It has no constant light output of 130 lumen it dims but it is still glowing 80 hours. That was always the case with maglites(and other lights to)
Just a little calculation:
If we say the the light is efficient with 100lm/W, we need 1.3W power.
3D cells have 4.5V we need around 0.3A to power it.
0.3A*80h=24Ah so it’s impossible…
But don’t underestimate normal batteries. Alkalines have huge runtimes on very small current and when the current even gets decreased by decreasing voltage it runs very long.
Capacity of an energizer D cell at 0.25A is around 14Ah
Mag’s 2D and 3D are actually well regulated with buck-boost drivers. I saw a runtime test (3 years ago and now lost on CPF) that the latter did about 16 hours of constant output.
Regardless, Werner is right. The 3D will have an extremely long taper after the light drops out of regulation.
The Niteize dropins probably perform similarly in that regard. How long they’ll provide useful light will depend on their respective circuits’ designs—i.e. how current draw tapers off below a certain low-voltage threshold.
