What is the Tailcap Current of the Malkoff M61???

On Malkoff site it states
"Below 3.4 volts it will drop out of regulation and run direct drive. "

My thinking is that I can stick a M61 in a hosts that will take 2 NiMH AA Tenergy cells or a hosts that will take a single AW LiFeP04 3volt lithium.

I have both of these hosts and if the M61 does go Direct Drive the current could be as high as 2A:naughty::naughty::naughty: Maybe it also means 400 lumens too.

What is the TailCap current on the M61 at 3.4V and below???????

Using a regulated DC power supply the M61 does not even start to turn on until 2.5V with only 10mA of current.

2.7V 0.11A
2.8V 0.17A
2.9V 0.26A
3.0V 0.35A
3.1V 0.48A
3.3V 0.76A
3.5V 1.00A it is now at regulated power and current drops from here
3.6V 0.92A
3.7V 0.89A
4.0V 0.86A
4.2V 0.83A
4.5V 0.79A
5.0V 0.72A
5.5V 0.65A

It should run well and does off of one lithium Ion. It will not run off of 2 AA NiMH, might just barely turn on. 2AA alkalines will run it but only at 1 watt of power roughly.

Sample base of one so the numbers may vary from module to module within a reasonable % but I still would not expect any to really work with the low starting voltage of 2AA NiMH rechargeables that at best would be 2.5V at turn on. G.

Is it safe to use non-protected Li-Ion cells from laptop packs? I have been using them with great success for the last year with M60L, I can immediately tell when it gets below 3.7V and below regulated.

If that's the case with M61 at 3.5V, I am worried that 3.5V is too deeply discharged for Li-Ion, or is it?

Wow, so the M61 draws quite a bit less current than my M30W which pulls well over 1.5v on a fresh 18650. I'm quite happy as I find very little use for low run time lights.

Thanks MrGman...


I guess my evil plan failed.

bigchelis said:

Thanks MrGman...


I guess my evil plan failed.

Click to expand...

thats the difference of something with buck versus boost drivers. Below the starting voltage of a boost drive current draw goes down not up. So current draw from the battery will actually diminish and the light output will diminish as the voltage sags lower and lower, you will get a much longer run time of less and less light and can never full drain the batteries 100% as you reach the cut off voltage to the circuit. This makes for a great 1X18650, 17650 run flashlight.

You could run 2X14500's in your 2AA host, but not NiMH.

M61 and nickel-zinc (NiZn) AAs

3.5V 1.00A it is now at regulated power and current drops from here
3.6V 0.92A
3.7V 0.89A
4.0V 0.86A
4.2V 0.83A
4.5V 0.79A
5.0V 0.72A
5.5V 0.65A
G.[/QUOTE]

For AA users, the M61 would be ideal in a 3xAA Dereelight body and 3 nickel-zinc cells (4.8-5.1V under a 1A load).

What is the Ahr rating of the nickel zinc cells?

Re: NiZn capacity, self-discharge rate

Axion said:

What is the Ahr rating of the nickel zinc cells?

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As I recall, it's about 1600 mAh at a discharge rate of 1A, maybe 1500 mAh at 2 amps. The self-discharge rate is better than regular NiMH but nowhere near as good as low-self-discharge NiMH cells like Eneloops. Also, NiZn cells, like lithium primary cells, work great in cold weather.

bigchelis said:

My thinking is that I can stick a M61 in a hosts that will take 2 NiMH AA Tenergy cells

Click to expand...

MrGman said:

It will not run off of 2 AA NiMH, might just barely turn on. [...] Sample base of one so the numbers may vary from module to module within a reasonable % but I still would not expect any to really work with the low starting voltage of 2AA NiMH rechargeables that at best would be 2.5V at turn on. G.

Click to expand...

I was wondering about this a while back, so I posted a query about trying out the M61 on 2x AA NiMH back in the main M61 thread on page 29:

Kestrel said:

Since Rat6P came up with the M30 / 2xAA NiMH combo,
and GreyShark came up with the M60LL / 2xAA Alkaline combo,
and 'yours truly' first demonstrated the M30 / 2xC & 3xC Alkaline combo,
and etc gave us the first review of an M30 / 3xAA combo - including CPF's highest performance ever carbon-zinc cell demonstration,

I'm pretty curious, has anybody tried their M61 on 2xAA (NiMH) yet?
I'm wondering if it would be at all useful on that low of a voltage.

Click to expand...

scot said:

Hey Kestrel you got me thinking, so tonight I grabbed my MD3, took out the 18500's and put two Duraloops in. I have no light meter, so I bounce the beam off the ceiling and look at an eye chart that's on the wall, sometimes comparing different lights.

Tonight with the MD3 and Malkoff M60, the bounce was very comparable to level 3 on a Surefire U2. (If level 1 is the lowest and 6 is the highest. U2 with 18650)

MD3 with M61 and Duraloops, at least as bright as level 4 on the U2!! I was shocked...very useful beam with plenty of light. Curious how long the AA's will run on this setup. Definitely not a very scientific test yet useful for my needs.

Try it, you may be surprised!!

Click to expand...

BigHonu said:

Just as a point of information to those wondering about the M61 on 2xAA:
I tried running the M61 in a MD head on 2xAA Eneloops on a 3x123 MD body very briefly.
The cells were charged a couple of months ago, and I did not check them prior to using them. Just plopped them in.
Output was WAY down. Almost like running the M61 with 2-stage ring on low with an 18650. Possibly a little brighter than that. Could very well be that the cells were not up to snuff so I'm going to try again sometime this weekend with cells fresh off the charger, or maybe even a couple of lithium AAs.

Click to expand...

So for scot's unit above, it sounds like the M61 could have been ~25+ lumens or so on 2xAA NiMH (which is merely a (lowball) estimate of the U2's 18650-output on level 4 - ~medium) - however, that is just his eyeball comparison with his U2. Sounds like BigHonu's test may have been less output than that (??), but he was unsure of the state-of-charge for the cells. He did make a comparison in that output was comparable to the 2-stage ring 'low' with the M61, is there an estimate of that output available?

An actual experiment is most certainly better than merely guessing without actually trying the configuration, though.

It would be pretty easy for anyone who has an M61 (I don't) to try this out. I'm surprised that more folks haven't tested this just out of curiosity. :shrug:

I'm wondering how all you folks actually get an M61??? Whenever I look they're out of stock.

recDNA said:

I'm wondering how all you folks actually get an M61??? Whenever I look they're out of stock.

Click to expand...

Sign up for e-mail alerts when it's back in stock is how I got mine.

And it's worth every penny.

Kestrel said:

I was wondering about this a while back, so I posted a query about trying out the M61 on 2x AA NiMH back in the main M61 thread on page 29:






So for scot's unit above, it sounds like the M61 could have been ~25+ lumens or so on 2xAA NiMH (which is merely a (lowball) estimate of the U2's 18650-output on level 4 - ~medium) - however, that is just his eyeball comparison with his U2. Sounds like BigHonu's test may have been less output than that (??), but he was unsure of the state-of-charge for the cells. He did make a comparison in that output was comparable to the 2-stage ring 'low' with the M61, is there an estimate of that output available?

An actual experiment is most certainly better than merely guessing without actually trying the configuration, though.

It would be pretty easy for anyone who has an M61 (I don't) to try this out. I'm surprised that more folks haven't tested this just out of curiosity. :shrug:

Click to expand...

and what would the real point be? You get a light that comes on at only 10% of its full output rating with 2AA batteries that are freshly charged up to peak and run time before cut off would be what? There is probably some variation from module to module. But coming on at 2.5V and about 10 ma and jumping up to 110mA at 2.7V says that with freshly charged NiMH batteries at their peak giving something like 2.6V under a very light load to give somewhere between 25 to 100 milliwatts of power to run the light for a while is good for what exactly? Without being used the NiMH battery voltage is going to sag and so you EDC that and go to turn it on after 3 days and get possibly nothing, maybe you can just barely see the LED glow. Not always going to keep the NiMH batteries topped off to peak just to get 25 lumens out of a 260 Lumen rated module. It will actually run off of 2 cheap alkalines that put out 3 volts much better since the current draw is still low but you could get it up to about 1 watt of power.

It will work fine off of a 3 AA stick for any one who likes something that long.

What would really be great if Solarforce of some other company came up with a 3AA host that was short and a fatter of the same configuration of the 3AAA type hosts that would take all these P60 size modules. That would run the M61 very well.

MrGman said:

and what would the real point be?

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previously posted:

Kestrel said:

[...] curiosity. :shrug:

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So as we can see here, actually testing a configuration is often more effective than not knowing what will happen but talking as if one does.