Zebralight moonlight mode duration test thread

[Mr Floppy]

All these durations would probably last 50% longer on an alkaline battery, due to the very low currents being used. I don't want to test that, because I don't trust that an alkaline wouldn't leak when it gets down to 0.85 volts.

I tried a 0.63V alky and it would not even start up a H51w. Using a 1V alky, I could not switch to any modes and it came on in sort of a medium-low mode. This is a H51w (third revision I think). It may be different if you start it off with a new battery though.

That said, I think you can get 150 hours at 10mA constant draw from an AA down to 1V.

How good are your multimeters folks?

 

[18650]

Very interesting results... Since the current draw is the same but longer runtime maybe the battery has something to do with it? Or possibly more efficient circuitry?

Since we're dealing with semi-conductors here, my guess would be the voltage drop across the LED isn't the same. I haven't looked at Cree datasheets for that spec but I'd imagine there's a range +/- around the rated voltage.

 

[WalkIntoTheLight]

Tailcap current with a fully charged Duracell StayCharged): 5.2 mA (sic) It's the same as WalkIntoTheLight's Sc52w-L2. Since my SC52 ran several days longer, I had expected a lower current draw. :thinking:

If you're drawing the same current, it has to be a higher capacity battery. Eneloops tend to be around 1900mAh (I'm not sure exactly what mine are, but probably around that). I suspect the Duracell has more capacity.

 

[Swede74]

If you're drawing the same current, it has to be a higher capacity battery. Eneloops tend to be around 1900mAh (I'm not sure exactly what mine are, but probably around that). I suspect the Duracell has more capacity.

I should probably clarify: I used a Duracell StayCharged to measure current draw because the Eneloop used for the runtime test was then on the charger. Today I measured tailcap current from six different cells: four half-empty budget Gen 2 NiMH called CoTech Ready to Use 2300 mAh and two fully charged Eneloop 1900 mAh.

The CoTech cellls all drew ~5.7 mAh, and the Eneloops ~4.5 mAh. So, I think it's safe to say that my SC52 drew a lower current from my Eneloop than WalkIntoTheLight's did from his. I'm sorry to have caused confusion, I should have been more clear that I was using a different cell for the tailcap current measurement than for the actual runtime test. I also should not have assumed that it's the flashlight alone that determines current draw.

Well, we all live and learn, and we all know what assuming makes of you and me. I'd like to say it won't happen again, but it probably will.

 

[WalkIntoTheLight]

Today I measured tailcap current from six different cells: four half-empty budget Gen 2 NiMH called CoTech Ready to Use 2300 mAh and two fully charged Eneloop 1900 mAh.

The CoTech cellls all drew ~5.7 mAh, and the Eneloops ~4.5 mAh. So, I think it's safe to say that my SC52 drew a lower current from my Eneloop than WalkIntoTheLight's did from his.

That makes sense. It seems there's a wide variation in currents used for moonlight mode (and likely brightness).

And yes, I've also noticed that the current draws are very different when testing with cells of different voltages. This makes sense, as I think it's fairly clear that the moonlight mode is regulated, so will draw a higher current as the battery depletes (and the battery voltage drops).

So it looks like Zebralight's claim of 3 weeks may be possible on some samples. I don't think their claim of 0.34 lumens is true if you get 3 weeks on an Eneloop, but perhaps on some samples you might get brighter moonlight modes with shorter run times.

Anyway, it was interesting to test it out.

 

[reppans]

...I don't think their claim of 0.34 lumens is true if you get 3 weeks on an Eneloop, but perhaps on some samples you might get brighter moonlight modes with shorter run times..

Do you believe the 0.34 lm claim to be true on your shorter 2-week samples?

 

[WalkIntoTheLight]

Do you believe the 0.34 lm claim to be true on your shorter 2-week samples?

No. If I had to guess, I'd say somewhere between 0.1 and 0.2 lumens.

I think the medium modes are pretty accurate to ZL's specs, but the highest and lowest modes tend to fall short.