Malkoff M61LL runtime

[Quiksilver]

Just curious ...

Which has longer runtime with the Malkoff M61LL:

2xCR123 or 3xCR123? 6 volts or 9 volts ... ?

First assumption would be the 3-cell configuration, however I saw a chart somewhere which compared this and I believe it depicted the 2-cell config as having the longer runtime due to lower output.

Assumption is SureFire 6P v. 9P w/ McClicky switch and M61LL module and fresh cells.

Thoughts?

 

[Kestrel]

This is a very good & interesting question, as I am quite familiar with the prior topic (M60LL: 18 hrs on 2xCR123, ~10 hrs on 3xCR123 @ substantially higher output). While the full-power M60 (& most likely the M61 as well) exhibited longer runtime at the higher voltage (as expected), the -LL version seemed to be different in this respect.

I have been keeping a close eye on any new info related to this (i.e. the M61LL) but to my knowledge, nobody has posted with hard info on this aspect.

Good luck,

 

[purelite]

I would like to know this also . I cant tell what my runtime is yet. I am using 2xAW 18650 2900mah batts and had the M61LL shut off way early. I am thinking it was my charger which wasnt getting the cells above 3.9volts but even at that voltage they should have had 75% capacity. So I got a new charger and it brings them to 4.1v and I am testing again over time since I am tailstanding the light while watching TV about 2-3 hours a nite. Not scientific really but I will get a rough idea. I was thinking I would get 17hours full output on 2x18650s since 2 cr123s are supposed to get 10hrs that should be a conservative estimate. But that premature shutoff could be the charger or a bad battery .

I did try putting 2 1.6V aa batteries in the host with M61LL with a dummy cell and output was very low but it worked. Havnt tested runtime on that but I think I will have to now just to test this theory. If it is tru I will switch my host setup to something that can hold 4 AA cells .

If runtime decreases with higher voltage that would seem silly to me and I dont think I would understand the reasoning behind it. It has always been the other way around , more voltage = longer runtime since the current draw is lower. This is evident in all the descriptions of all the Malkoff dropins isnt it?

 

[Kestrel]

The original M60LL was definitely different than the M60 in this way. On ~7.5 Vin (3xCR123 & 2xLiIon) it apparently had an output comparable to the -L, with resultant runtimes less than expected for the cell capacities. I would expect that this is the lower-than-expected runtime that you are obtaining with 2x18650's (although you're getting more output to compensate).

Again, I am most curious to see if the M61LL exhibits the same behavior - as you (purelite) seem to be describing.

 

[purelite]

After reading about the differences in output (brightness) I put the M61LL against my Fenix LD15 loaded with one of those 1.6volt AAs. Now the LD15 is rated at 70 lumens I think? and it is a bit briter on the 1.6V . when whitewall compared to the M61LL They are close , the M61LL has a tighter smaller hotspot and the tints are totally different but I would say they are almost identical in output as far as "briteness"

 

[BIG45-70]

Wow talk about timing. I plan on running the exact same setup. A 9P with a malkoff m61llw. I always assumed I would get 50% more runtime on 3 cells, equalling 15 hours. This is incorrect?

 

[Kestrel]

Wow talk about timing. I plan on running the exact same setup. A 9P with a malkoff m61llw. I always assumed I would get 50% more runtime on 3 cells, equalling 15 hours. This is incorrect?

Yes, if the M61LL driver performs comparably to the M60LL driver. I've been keeping a very close eye on this over the past few years and there has not been a definitive CPF post whether this is the case or not.

The flip side is that the posted runtime for the M60LL on 2xCR123 was ~8 hrs, however test data by bigwaffles demonstrated ~18 hours of regulated runtime. Although it decreased to ~10 hours (at ~M60L output levels) with 3xCR123, we were still considerably ahead of the game with regards to our performance expectations of the M60LL module. No wonder the ~60 lumen / ~2.5 hour SureFire P60LED module got discontinued. :rolleyes:

So yes, I've been very curious about the M61LL in this respect, as I very much prefer three-cell SF bodies. :shrug:

 

[whistrot]

I got a M61WLL (3700 K version) recently and put it into a Surefire 6P host (+ A19 extender). Measuring brightness and tailcap currents for various battery configurations gives these results:

2x eneloop AA - 2.4 V - 20 mA - 10 lm
1x AW 17670 - 3.7 V - 115mA - 35 lm
2x Surefire CR123A - 6.0 V - 100 mA - 59 lm
2x AW 16340 - 7.4 V - 105 mA - 67 lm
3x Surefire CR123A - 9.0 V - 105 mA - 71 lm

The 3-cell configuration with CR123 is slightly brighter than the 2-cell configuration, but the runtimes should be similar.

 

[Kestrel]

Very very interesting, thanks for the test data, whistrot. So if we make some rough wattage calculations:

2xCR123: 0.10A x ~5.0v (the generally-accepted voltage of two CR123's under load) = ~0.50 W
2x16340: 0.105A x ~7.4v (V under load) = ~0.78 W
3xCR123: 0.105A x ~7.5v (same) = ~0.79 W

So the total wattages are not held constant at the two different input voltages, which contrasts with the relatively-well-characterized M60/M61 driver behavior. Therefore, we should get some increased output, as shown in your output data.

Another interesting thing is that 2xCR123 vs 3xCR123 runtimes should be very similar as you noted from your tailcap draws. While this behavior is not as dramatically different as the M60LL driver behavior, this is still different than what we would normally expect, i.e. 50% greater runtime with the third CR123. Very interesting.

 

[RI Chevy]

I got this from the Elzetta website: This is of course for an M60, but just food for thought.

What is the advantage of a 3-Cell Model? 3-Cell models provide 50% longer run time than 2-Cell models, operate at lower surface temperatures, and offer more area for grasping the light. 3-Cell models are therefore excellent for hand-held use.

What is the run time of the Elzetta ZFL-M60 Tactical LED Flashlight with a fresh set of batteries? 2-Cell models produce 235 lumens of light for 1.5 hours and then continue to produce useful light for approximately 6.5 hours (8 hours of practical run time). 3-Cell models produce 235 lumens for 2.5 hours with extended usefulness for approximately 10 hours (12 hours of practical run time). The 'Low' setting on High/Low Tail caps produces 15 to 20 lumens for 40 and 60 hours on 2-Cell and 3-Cell models, respectively.

And this from illuminationsupply website: A guide with runtimes for malkoff devices dropins.

lluminationsupply.com/malkoff-devices-c-3.html?zenid=8dae73837f476fe112723a82307ba587

This stat for the M61WLL
Quick Specs:
Output: 70 Lumens
Tactical Runtime (2-CR123A): 10 hours
Useful Runtime (2-CR123A): 16 hours
Input Voltage: 3.4-9V
Throw: 75 Feet

 

[Kestrel]

I got this from the Elzetta website: This is of course for an M60, but just food for thought.

What is the advantage of a 3-Cell Model? 3-Cell models provide 50% longer run time than 2-Cell models [...]

The driver behavior for the M60 has already been well-characterized:

M60__from Regulated power supply,
Volts___amps___watts______,
3.0_____0.09____0.27__,
3.2_____0.22____0.70__,
3.5_____0.38____1.33__,
3.6_____0.51____1.84__,
3.8_____0.66____2.51__,
4.0_____0.86____3.44__,
4.2_____1.08____4.54__,
4.5_____0.85____3.83__,
4.7_____0.88____4.14__,
5.0_____0.80____4.00__,
5.5_____0.74____4.07__,
6.0_____0.69____4.14__,
7.0_____0.60____4.20__, (7.5 Vin interpolates to 0.58 amps, compare this to 0.80 amps from 2xCR123)
7.9_____0.56____4.42__,
8.0_____0.53____4.24__,
8.4_____0.50____4.20__,
8.5_____0.49____4.17__,
9.0_____0.47____4.23__,
9.5_____0.45____4.28__,

(emphasis and interpolation comment added by me)

The wattage is held roughly constant through the voltage range of interest, so the current draw of the M60 decreases proportionally as input voltages increase beyond nominal.

As noted in prior posts here, the -LL driver appears to behave differently.

 

[BIG45-70]

Now to figure out runtime on a set of AA's. I threw a pair of duracells in my 9P last night and was very surprised at the level of brightness the m61llw achieved. It's incredibly useful.

 

[Tommygun45]

I am interested in this as well as I was considering having my ultimate bug out light be my M61LL in either a cerakoted bored c3+a19 or the MD4 for the low mode. Either of those stacked with 2xaw2900s. I did a test with my e1e body and vme head and my M61LL ran on full brightness for 5 hours and 15 minutes on a fully charged AW RCR123. It quickly dimmed to maybe 1 lumen before shutting down at about 5:40. There was also 0 noticeable heat in the body of the e1e or the vme head.

 

[Kestrel]

Now to figure out runtime on a set of AA's. I threw a pair of duracells in my 9P last night and was very surprised at the level of brightness the m61llw achieved. It's incredibly useful.

For those who missed it the first time around, check out Greyshark's thread on the M60LL with 2xAA alkalines, well worth reading.

I expect that if anything, the M61LL will be even better in this regard due to the slightly lower Vf of the XP-G being that much closer to the Vin from 2xAA alkalines (somewhat higher than normally expected for the alkaline chemistry due to the relatively low current draw in this configuration).

 

[BIG45-70]

Thanks for that link I had not seen it. I guess this setup is truly the ultimate BOB/camping setup. I can't wait to see what Gene brings out next.

 

[Kestrel]

Yep, Greyshark's thread has a reference to Bigwaffles and the runtime graph in post # 244 in his thread, which is where it all began:

• M60LL on 2xCR123's, 18 hrs of flat regulated output
• M60LL on 3xCR123's, 13.5 hrs @ 75% greater output (~140 lumens estimated)

Plus that runtime graph put the nail in the coffin for the mediocre and much-maligned SureFire P60LED dropin ...


Edit: You know, it's funny. Since the XP-G's and XM-L's were released, I've upgraded all of the P60-style SureFires in our household, with the exception being the classic M60LL. I guess an M61LL should be a slight improvement, but it's never been that much of a priority for me - the M60LL is pretty much a legend in CPF, for very good reason.

 

[T45]

....still waiting for a run time test on the Malkoff M61LL running on 3xCR123 batteries.

 

[etc]

I got a M61WLL (3700 K version) recently and put it into a Surefire 6P host (+ A19 extender). Measuring brightness and tailcap currents for various battery configurations gives these results:

2x eneloop AA - 2.4 V - 20 mA - 10 lm
1x AW 17670 - 3.7 V - 115mA - 35 lm
2x Surefire CR123A - 6.0 V - 100 mA - 59 lm
2x AW 16340 - 7.4 V - 105 mA - 67 lm
3x Surefire CR123A - 9.0 V - 105 mA - 71 lm

The 3-cell configuration with CR123 is slightly brighter than the 2-cell configuration, but the runtimes should be similar.

Here goes the necrobump of the decade, but this is exactly the data I have been looking for and somehow lost this post.

I am not sure what difference between M61LL (regular white version, not "W") on 3x123 and 2x123 is lumens-wise but I will go with your version. The thing that bothers me with the above analysis is the flaw that the runtime will be the same on 2x123 and 3x123. The difference is 100 mAh drain and 105 mAh drain, respectively, but 3x123 has a bigger capacity.
To be precise, it's 1550*3V*3 and 1550*3V*2, which is 13.9Wh and 9.3Wh.
Considering the drain, the above equates to about 13 hours for 3x123 and 9 hours for 2x123. This is a rough estimate, I think real values are different and bigger, because mAh changes as it goes out of regulation, so both numbers will be different, but the ratio in runtime will remain. the 2x123 configuration appears to have about 70% of the runtime of the 3x123 configuration.