Malkoff M60 Time to Temp chart

The M60 seems to heat up slowly in a metal bodied light. Here's a chart showing the temps in a SF 6PD, light held vertically (supported by a wooden handscrew). Average temp rise of about 2[SIZE=-1]°F per minute.

Time..........Temp
0...............62.0
1...............64.5
2...............68.5
3...............71.5
4...............74.5
5...............77.0
6...............79.5
7...............82.0
8...............84.5
9...............86.5
10.............88.5
11.............90.5
12.............92.5
13.............94.0
14.............96.0
15.............97.5
16.............99.0
17.............100.5
18.............101.5
19.............103.0
20.............104.5

Setup was the same one shown in post #17 of this thread:

https://www.candlepowerforums.com/threads/190430

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This is really useful info. Nice work! The only time I would have a light on for this long is in candle mode lighting up a room, so your set-up matches those conditions. Others might wonder how much less the light would heat up if held in someone's hand. Any plans to run a similar test on the horizon?

Also, a note: the temps you report are of the bezel, not the drop-in, correct? In other words, the metal bezel seems to be doing a good job of conducting heat away from the drop-in. Any idea how hot the drop-in itself is getting?

Did you by any chance continue the test until the temperature stabilized?
At the 20 minute mark, the temperature still seemed to be rising at 1.5 deg
per minute.

George

how much less the light would heat up if held in someone's hand.

Click to expand...

As soon as the test hit 20 minutes, I grabbed the light in hand & read the temp - it immediately dropped 6[SIZE=-1]° due to conduction. It would seem reasonable that, assuming the operator's hand is 98.6[/SIZE][SIZE=-1]° F, the 'cooling effect' of the hand would start as soon as the body of the light reached that temperature.

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the temps you report are of the bezel, not the drop-in

Click to expand...

That's correct. The centerline of the infrared thermometer was placed at the center of the flashlight head, halfway between the bezel ring & the bottom of the head where it attaches to the battery tube. To measure temp at the body of the drop-in, a thermocouple would have to be attached to the drop-in, which I don't have a way to do.

Did you by any chance continue the test until the temperature stabilized?

Click to expand...

I stopped at 20 minutes, only because this seemed like a reasonable time for continuous use of this type light. I am pleasantly surprised that a light with this much output generates such a small amount of heat - the battery tube was barely warm to the touch after 20 minutes. By comparison, the Surefire L4 feels really warm after five minutes hand held.

Intersting topic -- wondering how this compares to the regular incan P60 heatup (as it was intended for).

-TI

The Malkoff unit heats up slower.
MOst likley due to the epoxy holding the unit together.
Yaesumofo

tetra-ice said:

Intersting topic -- wondering how this compares to the regular incan P60 heatup (as it was intended for).

-TI

Click to expand...

Would it be possible to test it in your hand to see it "real world" like? I wonder if it tops off sooner or just slowly climbs to a new high/low.


Just wondering

I can certainly do a retest, hand held, with the light again in the vertical position. This does introduce the variable of my hand temp versus your hand temp, but should at least show the relative effect.

Here's the hand held test. As before, air temp in room at a steady 62[SIZE=-1]° F.

First, the temp of the contact surfaces of both left & right hands were measured.
Left fingertips......83[/SIZE][SIZE=-1]°
Left palm............89
Right fingertips....86
Right palm..........91.5


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[SIZE=-1]Since the room temp (and the light body temp) was almost 30[/SIZE][SIZE=-1]° cooler than hand temp, the light was immersed head down in a pan of warm water until the head stabilized at 81[/SIZE][SIZE=-1]°, then the test started. The light was gripped tightly with all four fingers & the thumb wrapped just below the head. The light was switched from one hand to the other every 60 seconds, as it became tiring to maintain a firm grip in only one hand.

Time..........Temp
0...............81.0
1...............83.5
2...............86.5
3...............87.5
4...............88.5
5...............90.0
6...............91.0
7...............91.0
8...............92.0
9...............93.0
10.............93.5
11.............93.5
12.............94.0
13.............94.0
14.............94.5
15.............94.5
16.............94.5
17.............94.5
18.............94.5
19.............95.0
20.............95.5[/SIZE]

Thanks again! What PayPal address should we use to send you donations?

Devil's advocate question (only halfway serious): Could the temps have been affected by evaporative cooling since the light started off wet?

Nice job on the testing!

I take it there was no noticable change in output at any temperature? It's possible there was some but not enough for the naked eye. Any chance you could LUX meter your next test? Maybe just one at the beginning, middle and end?

:twothumbs

Could the temps have been affected by evaporative cooling since the light started off wet?

Click to expand...

After removing the light from the water bath, I blew it dry with compressed air. Switching hands probably had a greater effect, as the warming light body went from one (somewhat) cooler hand to the other.

there was no noticable change in output at any temperature?

Click to expand...

To my eyes, it seemed constant. Next time I'll run a time vs. lux test, but expect the output to remain level as long as the light runs within regulation.

What PayPal address should we use to send you donations?

Click to expand...

At this rate, the batteries are lasting a long time ... still on the first set.

I took a nap the other day and the P3D P100 in my pocket somehow got turned on. I woke up thinking my pants were on fire.

Follow up - I noticed a sharp pain on my thigh yesterday morning. Looked and saw a 2nd degree burn mark where the P3D burned me through my pants.

Ouch!