Fun with a thermal imager and a lux meter

LED Flashlights – General Info
1

Decided to do a 15min torture test of all my different flashlights and record the temperature with my thermal imaging camera and the output with my lux meter. Before we dive into the test just keep in mind this was a very casual test and not meant to be super accurate. The lux was measure at a distance of about 9 ft so they are not good for comparing output between flashlights as for some lights the beams had not fully developed yet. All lights were started on their highest setting or on turbo. After the lights stepped down from turbo I did not switch them back to turbo.
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The lights.

Fenix PD35
Fenix TK22
Acebeam L30
Thrunite Tn32
Thrunite Tn40
Firefoxes FF4S 65watt HID
Maxabeam Gen 3
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The images

Fenix PD35

0min -Lux 963lux
30sec -Lux 917lux
6min -Lux 473lux

15min -Lux 475lux

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Fenix TK22

0min -Lux unknown
30sec -Lux unknown
6min -Lux unknown

15min - Lux 1133

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Acebeam L30
0min -Lux 3094
30sec -Lux 2500
6min -Lux 2200

15min - Lux 1530

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Thrunite Tn32
0min -Lux 19160
30sec -Lux 18610
6min -Lux 16500

15min -Lux 15850

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Thrunite Tn40
0min -Lux 34210
30sec -Lux 32320
6min -Lux 26000

15min -Lux 24560

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FireFoxes FF4 65watt HID. This one has more measurements as there were multiple stepdowns
0mins 65watts - Lux ~30000
3mins 40watts - Lux ~20100

6mins 40watts - Lux ~20900

9mins 25watts - Lux ~12000

15min 25watts - Lux ~10360

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Maxabeam 75watt
0min - Lux 151000
6min - Lux unknown

15min - Lux 131400

2

Nice tests. :+1:

3

Thank you. What I found most interesting was the fact that LEDs are not the only light sources that loose brightness as heat increases. This particular Maxabeam is the CSWL model and is powered off a 12 volt(actually 13volt) power supply thats running off 120v mains. So there are no batteries and thus no voltage sag there that would explain its loss of brightness. I guess the ballast dials back as the heat increases.

The FF4 also suffered an immense drop in intensity as the heat increases. In this case I think both voltage sag and heat are to blame. Its interesting to note that the Tn40 didn’t suffer nearly as much a drop in intensity as the FF4 over the same period of time though. It does appear that Thrunite is pushing the Tn40 much harder than FireFoxes pushes the FF4. In another unrecorded test I did a few days ago then TN40 reached almost 180 degrees and it still had not throttled back. Pretty hot for a flashlight if you ask me.

4

TN40 looks like it step down not enough. If it reach 180degree external, internal would be too hot.