Malkoff M61 SHO 1.25 hour run-time?

N/Apower · Oct 23, 2012

How is it possible, on 2 primaries, at full power, when it drops out of regulation at 5.5 Volts?

I admit that electronics are NOT! a strong point for me, but doesn't the voltage of a battery drop as usage continues? Further, isn't 0.25 volts a cell "normal sag"? Also, won't batteries stored for maybe 5-6 years not even have 5.5 volts in 2-cell configuration?

kyhunter1 · Oct 24, 2012

This module is more designed for 3 or 4 x 123's or 2 x Li rcr configurations. With the higher voltage setups, you will get the benifit of the longer dimming runtime instead of the abrupt cut off. It is designed to cut off at low voltage. 2 x 123's will fully power it for a while.

twl · Oct 24, 2012

First, let me say that I have not timed it, and am just going by the numbers.

Gene's site says it draws 1000ma(1 amp) at 6v. A normal good quality CR123 primary has 1500mah in it when new, and is about 3.22v under no load on a voltmeter.
With 2 of them, it's 6.44v(roughly, unloaded) and pulls down to let's say around 6v under load.
The regulator pulls an amp at 6v, and with 1.5 amp hours(1500mah) capacity at 6v, it "could" go to as much as 1.5 hours run time until total depletion.
Probably it will not go to total depletion under regulation, so it sounds plausible that it would run 1.25 hours regulated, and then have the short taper-off to finish up at 1.5 hours.

Perfectly feasible by the numbers. Perhaps expect a little less in the real world, based on some unexpecteds or unknowns, etc. But, pretty plausible as a general guideline.

N/Apower · Oct 24, 2012

twl said:
First, let me say that I have not timed it, and am just going by the numbers.

Gene's site says it draws 1000ma(1 amp) at 6v. A normal good quality CR123 primary has 1500mah in it when new, and is about 3.22v under no load on a voltmeter.
With 2 of them, it's 6.44v(roughly, unloaded) and pulls down to let's say around 6v under load.
The regulator pulls an amp at 6v, and with 1.5 amp hours(1500mah) capacity at 6v, it "could" go to as much as 1.5 hours run time until total depletion.
Probably it will not go to total depletion under regulation, so it sounds plausible that it would run 1.25 hours regulated, and then have the short taper-off to finish up at 1.5 hours.

Perfectly feasible by the numbers. Perhaps expect a little less in the real world, based on some unexpecteds or unknowns, etc. But, pretty plausible as a general guideline.

I do not understand, though, I thought as usage continued, voltage of the batteries dropped. My volt meter certainly seems to indicate this as such.

Grizzman · Oct 24, 2012

I also think that going from 6.44 volts down to the flashing stage at 5 volts would occur in less than an hour, with 1 amp being drawn.

I'm gonna sacrifice a couple cells, and will report the results in about an hour and a half.

The SF 123A cells have expiration dates of 08/2021. One outputs 3.235 volts, and the other one outputs 3.236 volts resting. The M61SHO is installed into a Malkoff MD2 with high low switch.

Grizz

S1LVA · Oct 24, 2012

S1LVA

Grizzman · Oct 24, 2012

At the 1 hour 15 minute mark, the drop-in looked like it was putting out full output.

After an hour and a half, the output was pretty much equal to an M61.

After an hour and 45 minutes, the output was roughly equal to an M61L.

After 2 hours and 20 minutes, the output is slightly less than an M61LL

Yep, it's still running. This isn't quite what I'd call a short taper.

Grizz

Cerealand · Oct 24, 2012

Thanks for the testing. If that's the short taper, his normal taper must be very very long.

Grizzman · Oct 24, 2012

Cerealand said:
Thanks for the testing. If that's the short taper, his normal taper must be very very long.

Definitely.

It's still running after 220 minutes. I'd guess the output to be around 40 or so lumens.

It just passed the 4 hour mark. It's putting out roughly the same output as an M61 on low, in an MD2 driven by two RCR123s.

If I hadn't physically seen my two M61's I'd think I messed up and ran this test with one of them.

I am impressed.

Grizz

Glock 22 · Oct 24, 2012

Very Impressive. Did you have any heat issues? The reason for asking is that I've not got to use mine hardly any yet.

Grizzman · Oct 24, 2012

It is now approaching the 5th hour of run time. It is still putting out as much as an M61 on low driven by two primaries. I'll stop the test at the hour, cause it's gonna be bed time before this sucker gives up.

I was artificially cooling it, so I can't say how hot it would have gotten. I've used it quite a few times up till now, but never for more than a couple minutes at a time.

Grizz

N/Apower · Oct 27, 2012

Very impressive!

Glock 22 · Nov 7, 2012

Grizzman said:
I was artificially cooling it, so I can't say how hot it would have gotten. I've used it quite a few times up till now, but never for more than a couple minutes at a time.
Grizz

I did a runtime with mine on 2x 18500's it ran 1hr. and 40mins. with no real big heat issues. I left it setting on my computer desk and ever so often I would pick it up and it would be a little warm, but by just holding it a few seconds it took care of that. Awesome drop-in.

Grizzman · Nov 7, 2012

Thanks for testing this.

Did you do anything to improve the standard thermal path in your 9P?

Grizz

Glock 22 · Nov 7, 2012

Grizzman said:
Thanks for testing this.

Did you do anything to improve the standard thermal path in your 9P?

Grizz

Your welcome, the only thing my 9P has different is a McClicky in it and I wrapped the module in aluminum foil.

ampdude · Nov 7, 2012

N/Apower said:
Also, won't batteries stored for maybe 5-6 years not even have 5.5 volts in 2-cell configuration?

Lithium primaries should still be well over 3.1 volts (closer to 3.2 and maybe still over) apiece after 5-6 years unless they were stored at 110 degrees or something ridiculous, then all bets are off.

Malkoff M61 SHO 1.25 hour run-time?

N/Apower

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