Malkoff M60LL On 2x AA

I've been running an M60W on 2x AA's in my C3 for a while now as a way to get a low mode or scrounge batteries. I've tested it up to 2 hours runtime so far and I'm pretty sure it'll go longer but I get bored and distracted easily so I've never done a thorough test.

Well tonight it just occurred to me try my M60LL on 2x AA on the theory that perhaps it will draw fewer mah's than the M60W and therefore get a longer runtime if I have to scrounge for batteries in the advent of a disaster. Hurricane season fast approaches...

so... much to my surprise the output of the M60LL on 2x AA seemed barely diminished compared to its output on 2x CR123 primaries. In fact those were the same two AA's that had already run my M60W for 2 hours! The M60LL actually blows away the M60W's output when run on 2x AA. I don't understand all the electronics very well but my guess would be that the M60LL drops voltage to the LED to something very near 3 volts so the AA's are supplying almost all the driver wants anyway.

Now my question is how exactly do runtime calculations work for these LED drop ins? It appears that more batteries give a longer runtime even in series so it seems there's some kind of capacity stacking going on as a result of the driver. At 2700mah each those AA's could potentially provide quite a bit of runtime. I might have to get a fresh set and tough out a runtime test from beginning to end.

I run M30 on 3xAA (FiveMega body)

Brighter than M60.

In fact runs on any kind of AA cell.

etc said:

I run M30 on 3xAA (FiveMega body)

Brighter than M60.

In fact runs on any kind of AA cell.

Click to expand...

Try running it on a 4/3af cell and watch the runtime you get!

That's an interesting rechargeable option for a 4 cell light. I could use an extender on the C3 and gain another 1,000+ mah. In the meantime I'm going to bite the bullet and do the AA test.

I'm about 7 hours into the test with 2x Duracell alkaline AA's and I would guess the output is around 40 lumens. It's still appreciably brighter than a standard M60 on 2x AA. I was hoping the AA's would hold the brightness a bit longer but it's still very usable.

After 16 hours the output has diminished to what I would guess is around 15 lumens, about the same as a full power M60 on 2x AA. It's still enough light to navigate around the house or do close up work. There's enough light to bounce of the ceiling and dimly illuminate a small room.

It's been 22 hours so far and it's still putting out light. It looks like 15 or so lumens still. This seems to imply that the voltage is the bottleneck, not the mah's. It may well continue to run at this dimmer level for a long time to come. It will illuminate the inside of my shed from 100 feet away dimly but well enough to see what or who may be in there.

Thanks for all the info GreyShark! I've been considering an M60LL for a while now and knowing that I can run it on AA batteries makes it that much more appealing. Thanks!

It has now been over 30 hours and it's still going. The output has dropped considerably, at this point usable throw is only about 30 feet. It's still bright enough to be useful indoors or close up, it'd be very welcome during a prolonged power outage.

BTW, the bezel has remained cool to the touch throughout this entire test.

It's up to 39.5 hours. The output has fallen since my last update. It's still enough to find your way around the house or read by. I think it's safe to say the M60LL is definitely hurricane ready!

Gah! You're not supposed to be helping me spend money!

:thumbsup:

-Trevor

Edit: If you don't mind my asking, where did you get your FiveMega AA bodies?

I actually use 3x CR123 hosts, specifically a SureFire C3 Centurion and 6P with A19. The AA's fit fine with no contact issues, just a little bit of rattling if you don't use an improvised spacer. The initial idea was just to determine how well my favorite drop in's would run on AA's if that was all I could scrounge up in a survival/disaster/travel scenario. What really impresses me about all this is that the M60LL on 2x AA is as powerful as an incan MiniMag is on fresh batteries, or much more so, for the first 24 hours! I've long since moved on to bigger and better things but for many years the 2x AA MiniMag was my EDC and mainstay of personal lighting.

The M60LL has got to be the most underrated Malkoff drop in out there. I'm going to have to see what it'll do on my other favorite batteries.

For what it's worth...

The behavior you're seeing is probably not specific to the M60LL. Any of the M60 variants (and any other drop-in with a buck converter that allows the emitter to be direct-driven when the Vbatt falls below the minimum required for regulation) will behave similarly. As I recall, the M60's are regulated at 3.8V and above, and thus will always be direct-driven by 2x alkaline cells. I don't know the minimum current required to light a Cree XR-E, but, from the graph in the data sheet, it looks like ~2.3-2.4V. The voltage of the alkalines will sag under load, but at the lower end of the input voltage range, the XR-E doesn't draw much current. So, the Vbatt will probably settle to some point and provide steady current for a good long time - as you're seeing.

A couple thoughts:

• 2x NiMH AA cells will be interesting. The output will probably be very low, and they may not light up some units at all.
• I'm also curious to see what kind of runtime you'd get from a pair of C cells (in an FM or TnC host for AW "C"s). I might have to assemble that and give it a try.
• I wonder if the Malkoff 4-6 cell Mag D drop-in uses the same buck converter? Think of the runtime you'd get with a pair D cells.

GreyShark said:

I actually use 3x CR123 hosts, specifically a SureFire C3 Centurion and 6P with A19. The AA's fit fine with no contact issues, just a little bit of rattling if you don't use an improvised spacer. The initial idea was just to determine how well my favorite drop in's would run on AA's if that was all I could scrounge up in a survival/disaster/travel scenario. What really impresses me about all this is that the M60LL on 2x AA is as powerful as an incan MiniMag is on fresh batteries, or much more so, for the first 24 hours! I've long since moved on to bigger and better things but for many years the 2x AA MiniMag was my EDC and mainstay of personal lighting.

The M60LL has got to be the most underrated Malkoff drop in out there. I'm going to have to see what it'll do on my other favorite batteries.

Click to expand...

If you don't mind 2x18650 length try it with 2 4/3a cells.

gswitter said:

For what it's worth...

The behavior you're seeing is probably not specific to the M60LL. Any of the M60 variants (and any other drop-in with a buck converter that allows the emitter to be direct-driven when the Vbatt falls below the minimum required for regulation) will behave similarly. As I recall, the M60's are regulated at 3.8V and above, and thus will always be direct-driven by 2x alkaline cells. I don't know the minimum current required to light a Cree XR-E, but, from the graph in the data sheet, it looks like ~2.3-2.4V. The voltage of the alkalines will sag under load, but at the lower end of the input voltage range, the XR-E doesn't draw much current. So, the Vbatt will probably settle to some point and provide steady current for a good long time - as you're seeing.

A couple thoughts:

• 2x NiMH AA cells will be interesting. The output will probably be very low, and they may not light up some units at all.
• I'm also curious to see what kind of runtime you'd get from a pair of C cells (in an FM or TnC host for AW "C"s). I might have to assemble that and give it a try.
• I wonder if the Malkoff 4-6 cell Mag D drop-in uses the same buck converter? Think of the runtime you'd get with a pair D cells.

Click to expand...

Check out post 242 in the link below.
https://www.candlepowerforums.com/threads/216438&page=9

Wow. Just when I though I'd be looking for a M30 for 2xAA, you bring back the possibility of an M60 (LL of course). Thanks for the test.

gswitter said:

For what it's worth...

The behavior you're seeing is probably not specific to the M60LL. Any of the M60 variants (and any other drop-in with a buck converter that allows the emitter to be direct-driven when the Vbatt falls below the minimum required for regulation) will behave similarly. As I recall, the M60's are regulated at 3.8V and above, and thus will always be direct-driven by 2x alkaline cells. I don't know the minimum current required to light a Cree XR-E, but, from the graph in the data sheet, it looks like ~2.3-2.4V. The voltage of the alkalines will sag under load, but at the lower end of the input voltage range, the XR-E doesn't draw much current. So, the Vbatt will probably settle to some point and provide steady current for a good long time - as you're seeing.

Click to expand...

Yeah, I actually started exploring this area with an M60W because I wanted to know what my EDC would be capable of on scrounged batteries. The point isn't the fact that it has a long period of decline in direct drive, it's that the M60LL is far and away brighter than the M60 or M60W when powered by 2x AA. The M60LL on 2x AA seems to be putting out about as much light as a P60 incan does on 2x CR123 primaries and it's doing this for a longer runtime than a P60 incan has on 2x CR123's. In fact it's by far the brightest 2x or 3x CR123 compatible lamp when run on 2x AA that I've tested.

The long dimming phase is just icing on the cake, I'm just trying to work out how much life I can get out of the batteries before they give up the ghost. Right now it's at about 44 hours and still delivering a useful level of reading light. If you've ever experienced a power outage lasting weeks or months you know how nice it is to be able to read after dark. An EDC that can make use of a wide variety of battery types and run well on them could come in pretty handy. This really has its roots with an earlier concept I was toying around with, keeping a 3V lamp in a spares carrier to exploit scavenged batteries. While the M60LL doesn't have the high end of the M60 it runs well enough on 2x AA that it more or less eliminates the need to have a special spare lamp assembly as long as you're ok with 80+ lumens on primaries or 17mm rechargeables.

Essentially the M60LL is the most omnivorous drop in that I've encountered so far and it's a Malkoff so you can trust the build quality.

A couple thoughts:

• 2x NiMH AA cells will be interesting. The output will probably be very low, and they may not light up some units at all.
• I'm also curious to see what kind of runtime you'd get from a pair of C cells (in an FM or TnC host for AW "C"s). I might have to assemble that and give it a try.
• I wonder if the Malkoff 4-6 cell Mag D drop-in uses the same buck converter? Think of the runtime you'd get with a pair D cells.

Click to expand...

My hotwire Mag runs on 3x 26700's rated at 3000mah. It has crossed my mind to get a low output LED module for it to yield some insane runtimes. Of course a 4c host isn't pocketable like a 3x CR123 host or one of the FM SureFire compatible C bodies. A fat Li-Ion host would be nice if you don't mind carrying it because it would have higher voltage and large capacity. You would have to use spacers for any other battery options though and the math gets weird on anything but a 100mm long battery tube which would be 2x C primary size.

malamalama said:

Wow. Just when I though I'd be looking for a M30 for 2xAA, you bring back the possibility of an M60 (LL of course). Thanks for the test.

Click to expand...

The M60LL won't be as bright as the M30 but it will be bright, have a long runtime and the M60LL can eat batteries that would kill an M30 so in that regard it's more versatile. I was considering an M30 as well until I saw what the M60LL can do. Now I don't see as much of a need for a specialized AA powered drop in for my intended purposes. I find the versatility offered by this module to be very appealing.

GreyShark said:

It's up to 39.5 hours. The output has fallen since my last update. It's still enough to find your way around the house or read by. I think it's safe to say the M60LL is definitely hurricane ready!

Click to expand...

thanks for this runtime test greyshark. :thumbsup:

gswitter said:

A couple thoughts:

• 2x NiMH AA cells will be interesting. The output will probably be very low, and they may not light up some units at all.

Click to expand...

i tried 2xNiMH AA's last night in a g3 with an m60LF and it's hard to say at this point what the output is. it does make an NT at about 1 lumin look like a thrower :devil: but i could clearly make out objects 20 feet away at nearly 180 degrees with no problem.