I'm using an M61 LL running off of 3 18650 batteries...how much run time will I get with that set up before it tapers to below 100 lumens? How much time will I get total before it would go completely dark? Any help would be greatly appreciated.
Malkoff M61 LL run time
- Thread starter ash211
- Start date
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Don't run it off of 3 18650's. Perthe Malkoff website "The input voltage is 3.4 - 9 volts. Below 3.4 volts it will drop out of regulation and run direct drive. " 12.6 volts is over spec, the drop-in may go completely dark from over voltage.
ebow86
Flashlight Enthusiast
Wow, running the M61 LL off of 3 18650's for how long now? I would have expected the M61 to have been burnt up by now, well over 12 volts going to a 9V drop-in? Not good. If you have been running that setup for any amount of time I would expect the lifespan of your M61 to have been severly compromised by now.
Whoops...I've been running it like this for a couple of hours total over a few months. So what you are saying is I've trashed my Malkoff and now can't use my 3 18650 body...great. So what's the formula? Each 18650 provides 4 volts and I need a bulb that can handle 12 volts total?
AaronG
Enlightened
That's about right. Have you noticed any drop in output? Can you remove an extension or is the body all one piece? Your only saving grace is that it's a low output module so it probably got a fairly high resistance.
A 9v dropin should be good for 2 18650 or 3 cr123. You would need a 12v drop in for your setup.
A 9v dropin should be good for 2 18650 or 3 cr123. You would need a 12v drop in for your setup.
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ash211,
Batteryjunction.com sells 'CR123a size dummy cell' units, as does Lighthound.com (although they cost more), if you don't want to buy a new body. You might want to use some sort of wrap or tubing, if you don't want those rattling around.
The M61LL runs for 10 hours regulated, on 2xCR123a primary cells, and - I think - a good 18650 is going to be very close to that (everyone feel free to jump on that if I've got that wrong), so, theoretically, you might get close to 20 hours on 2x18650. YMMV.
Something else to keep in mind: 3xCR123a is the length of 2xAA (roughly), so 3x18650 is roughly the length of 4xAA. That voltage range is going to work with any AA NiMH, alkaline (in an emergency), lithium primary, or NiZN (1.7 volts?) rechargeable. Just don't pop in any of the new batteryjunction.com 3 volt lithium primaries. You will want something to keep them from rattling around. I would suggest wandering the aisles of a good hardware store. Maybe plastic pipe, maybe vinyl tubing. You might need some sort of fibre washer inside the lens, to push the led module back, to help with connectivity, or not. I definitely need that sort of arrangement with a 9P & A14, when using 3xAA cells, but you have a different set-up. If the 4xAA length is right, buy yourself two CR123a dummy inert spacer cells, and you've got yourself a fairly versatile set up.
I don't have the thread reference handy, but someone ran a runtime test with the older Malkoff M60LL, and it was running (out-of-regulation) at 5 lumens after 80 hours (3+ days!), on 3xAA. It was not as bright as the full output at the beginning, because of the voltage, but ran longer. The increased voltage of 4xAA might or might not make it run harder, in regulation, with decreased runtime, but you could always get a dummy inert spacer AA unit (lighthound has them), and hopefully repeat the same results with the M61LL. The versatility of the M60/M61LL circuitry is phenomenal, the lack of a focused throwing-beam in the M61 far less important, and the emitter is more efficient. I've got two M60LL units, and I'm thinking of picking up an M61LL, even though I don't really need one. In certain ways, the M60LL/M61LL is probably the most versatile Malkoff drop-in out there.
Batteryjunction.com sells 'CR123a size dummy cell' units, as does Lighthound.com (although they cost more), if you don't want to buy a new body. You might want to use some sort of wrap or tubing, if you don't want those rattling around.
The M61LL runs for 10 hours regulated, on 2xCR123a primary cells, and - I think - a good 18650 is going to be very close to that (everyone feel free to jump on that if I've got that wrong), so, theoretically, you might get close to 20 hours on 2x18650. YMMV.
Something else to keep in mind: 3xCR123a is the length of 2xAA (roughly), so 3x18650 is roughly the length of 4xAA. That voltage range is going to work with any AA NiMH, alkaline (in an emergency), lithium primary, or NiZN (1.7 volts?) rechargeable. Just don't pop in any of the new batteryjunction.com 3 volt lithium primaries. You will want something to keep them from rattling around. I would suggest wandering the aisles of a good hardware store. Maybe plastic pipe, maybe vinyl tubing. You might need some sort of fibre washer inside the lens, to push the led module back, to help with connectivity, or not. I definitely need that sort of arrangement with a 9P & A14, when using 3xAA cells, but you have a different set-up. If the 4xAA length is right, buy yourself two CR123a dummy inert spacer cells, and you've got yourself a fairly versatile set up.
I don't have the thread reference handy, but someone ran a runtime test with the older Malkoff M60LL, and it was running (out-of-regulation) at 5 lumens after 80 hours (3+ days!), on 3xAA. It was not as bright as the full output at the beginning, because of the voltage, but ran longer. The increased voltage of 4xAA might or might not make it run harder, in regulation, with decreased runtime, but you could always get a dummy inert spacer AA unit (lighthound has them), and hopefully repeat the same results with the M61LL. The versatility of the M60/M61LL circuitry is phenomenal, the lack of a focused throwing-beam in the M61 far less important, and the emitter is more efficient. I've got two M60LL units, and I'm thinking of picking up an M61LL, even though I don't really need one. In certain ways, the M60LL/M61LL is probably the most versatile Malkoff drop-in out there.
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Gene43
Enlightened
Wow! That is amazing. I would never have thought it would survive. None of the critical components are rated for this. You are definitely in uncharted territory. I like to build things to last, but I really have no idea on this one.
geckoblink
Newly Enlightened
- Joined
- Jul 10, 2010
- Messages
- 75
I don't suppose you'd consider continuing to run it at 12.6 V . . . for science? :devil:
PoliceScannerMan
Flashaholic
Have you considered getting a 2x18650 body? Nite sells them on the marketplace for $45. You already have the tailcap, bezel, and 18650s, so there's no extra cost there. You'll get plenty of runtime, about 20 hours. Plus, the format is a lot handier than 3x18650s.
As for whether you should keep using the drop-in, or get another for work use, I think the answer depends on what you do for a living. My take is that if it's working, it's working, and it'll probably continue to work. In other words, if ain't broke, don't replace it.
-John
As for whether you should keep using the drop-in, or get another for work use, I think the answer depends on what you do for a living. My take is that if it's working, it's working, and it'll probably continue to work. In other words, if ain't broke, don't replace it.
-John
Um, light is very important to me in my line of work so i may have to swap it out for a new one just to be on the safe side. I have no idea why it hasn't blown yet...I've probably got about 10 hours through it with 3 18650's. I have a 2 18650 body but I use the 3 18650 body because it makes it long enough for me to quickly get it out of my pocket...the 2 18650 body is too short. I'm thinking of using 4 AA's...will this give me the standard duration/lumens for an M61 LL (100 lumens for 10 hours)???
The M61LL draws 0.9w of power (150ma at 6v, according to the Malkoff website). An Eneloop (AA) has 2.4w of energy (2000ma at 1.2v). So four AA Eneloops would have 9.6w of energy. 9.6w/0.9w equals 10.67 hours of light. This should be fully regulated throughout the run, since Nimh cells are basically empty at 1.0v. You can roll up thick construction paper to reduce the rattle inside the light.
Hopefully, somebody will be along to check my calculations.
For better fit, you might consider getting some 2/3 A Nimh cells, or even A Nimh cells. Battery Junction carries them under specialty cells. These hold more juice than AA cells, and would allow you more runtime. They also won't rattle as much in your light.
-John
Hopefully, somebody will be along to check my calculations.
For better fit, you might consider getting some 2/3 A Nimh cells, or even A Nimh cells. Battery Junction carries them under specialty cells. These hold more juice than AA cells, and would allow you more runtime. They also won't rattle as much in your light.
-John
