greatscoot
Flashlight Enthusiast
We should start a "What Will it Run Off" thread.
I'm telling you if gene posted the true voltage that his stuff could be run at it would be a huge selling point. I held off for years on getting a M91 because the listed voltage range didn't really work for me.
Which "last several" of my posts would those be?The irony with all of the 'quality content' of the last several of your posts, instead of you know, explaining why the JOKE that I made is so horribly wrong and disgusting? Or have I not yet met the limit of "informative posts" to make jokes in a General Topic thread?
It's funny you find problem with it, because in addition to having done many under voltage tests myself, many more like INFRNL, Thermal, Byk, BigBurly, and countless others, we know that there is actually quite a decent range of Malkoff devices that run exceptionally well under their rated voltage. Now if this is wrong, we would all I'm sure be most interested to hear more elaboration from your perspective, seeing how we are here seemingly only here for information and all....
God forbid we actually make this conversation you know, informative, or something.....
It's a simple question, but there's not a simple answer, as different types of LEDs with unknown specs are being used.Time to send more money to Gene and Cathy but can't decide on m91 vs m61. I know m91's run on almost everything, but can new m61s do the same under 9v? The only m61s I have left are 4L and I'm just curious about newer offerings. Option of using two aa's or a single primary is a big plus.Thanks ahead of time for any info.
It's a simple question, but there's not a simple answer, as different types of LEDs with unknown specs are being used.
Most of the time, when you look at a runtime chart of either, whether with primaries, or a single li-ion, you're going to see a period of regulated runtime followed by another period where the output tapers off as battery voltage decreases.
The longer it ran in regulation, when there was greater current demand, the less time it will run out of regulation, and vice versa.
A M61 or M91 isn't going to run in regulation on 1x123 or 2AA to begin with, so your regulated runtime is 0, and all you're getting is the long taper. Without a boost circuit, you're direct driving the LED with the batteries, so, all else being equal, the output and runtime will depend on the forward voltage of the LED(Vf).
This is where saying one is more suitable than the other gets tricky, because Vf is not a fixed number.
If you look at the specs of different Cree LEDs Malkoff has used over the course of time, you'll see their Vf rated like this:
XR-E 3.3V @ 350mA
XP-G 2.9V @ 350mA
XP-G2 2.7V @ 350mA
XP-L 2.9V @ 1050mA
The XP-L complicates things by being rated a 1.05A. Vf typically increases and decreases with drive current(the latter being what makes underdriving with even lower voltages possible), but that change is not linear. On top of that, I've read test results of XP-Ls being 2.87V@350mA, so who knows.
What we're not given is a minimum, rock bottom voltage at which a LED will turn on at all.
The newer SST-20 Hi CRI LEDs are also spec'd at 350mA, but have additional binning information that separates them into 3 Vf groups of 2.5-2.7, 2.7-2.9, 2.9-3.1(and you can't order specific Vf groups). In other words, and it's actually true for all of them, one might work better than another; they're not necessarily going to be consistent.
So yes, the M61 and M91 will both run at lower than specified voltage. As far as which might run longer, or with higher output, all we really have are indicators. And even those leave some play room, because they are based on ranges and unspecified minimum numbers.
The easy answer is "just take your pick", because that's really what it's going to come down to.
I'm not a fan of underdriving these lights, and also have my doubts about runtime tests where the light is left on for the duration, because I think there will be a point during that runtime that the light wouldn't come back on if switched off.
Sorry I messed up your runtime test, but that's what us trolls doRight now I'm testing an Elzetta Charlie with two AA rechargeables. When I read your post I switched it off and on again. True, it didn't come back on.
It ran for 40 Minutes on 2xAA rechargeable.
It came back on after some time and ran all together for 2h 45min.Sorry I messed up your runtime test, but that's what us trolls do