I’m thinking about getting either 3000k or 4000k version but I hate non rechargeable batteries
Also, the light seems to run direct drive under 3.4 volts
So I figured if I use 2 x 3.7 volts that should keep it in constant current drive
The description says it can run from 3-9 volts
Is this correct?
Yes.
I’ve been contemplating this application myself. I believe you are at least mostly correct. FYI: I just double checked, and my M61N draws 0.95A running on 1x18650, and 0.71A using 2x16340s at power-on (all protected ‘3.7/4.2V’ cells resting at ~4.1V no-load / OCV).
Due to the difference in cell capacity and IR (internal resistance) in the two cases, I’m not sure what the output/voltage/time graph would look like out into the discharge curve relative to that stated 3.4V direct drive threshold spec.
Re: the IR, that will be additive in any calculations using the 2x16340s, and the 16340s each have higher IR than the 18650 as well. We could be looking at ~4x difference in the total IR in the circuit in the two cases(?).
I’m still thinking about it myself;-)
I didn’t allocate enough time for this, so here’s an abbreviated runtime of the M61w (SST-20 3000K). The battery was at 3.28V (after resting overnight) after the test. Personally, I think it’s not worth it w/ the 3.4V driver and only w/ the 3.8V driver might two cells be worth it. You get zero LVP, so you need protected batteries. There aren’t many protected cells where two will fit without a body extender. 16340s will have much less capacity, so I doubt you get any more time in regulated output. Maybe 18350’s would. I don’t have any matched pairs of protected batteries that will fit in anything Malkoff.
Yes. I have used M 61s with rechargeable batteries for years. One or two cells work very well.
A few other questions for ya…
Is there any way you can take some beamshots of something like the interior of your house pointed at furniture or pantry in your kitchen something colorful, I can’t find beamshots anywhere, duckduckgo, google,etc…
I’ve only been able to find a couple of videos on YouTube but they’re really old and people don’t know how to use cameras, it makes this drop in look like it’s putting out 30 lumens, and yet, it says 400 lumens on malkoffs website.
Also, would the regulated runtime be longer using 2 x cr123 primaries cause of the fact that most 16340’s are like 900 mah, whereas, Energizer ultimate lithiums cr123 are 1500 mah.
I know you tested this with a 3500 mah 18650 already, but those are 3.7 volts
Would it make my h difference to use 2 x cr123’s or would it only be like 10 minutes longer?
Im thinking of maybe getting this drop in with a md3 body 3 x cr123 or 21700 tube
I’m trying to get the most amount of runtime I can get.
Read this.
I’m not inclined to spend $5+ to find out. But I am sure the proportion of runtime that is regulated will be higher. Whether they can actually run for ~100 minutes without any drop, I am skeptical. But maybe.
Here is with LFP rechargeable CR123’s. These are 3.2V batteries but very low on capacity. So it’s just to show what the curve looks like, not how long you can expect it to run on primary CR123’s. It’s regulated until the batteries are basically dead (which is why you will want protected cells). You get very little warning before it’s over-discharging batteries.
