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Ah ok gotcha
The flicker only started on mine at around the 2minute mark, >50degress at the heatsink so well past my pain threshold of a hot potato test
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With regard to the flickering, on mine it was pretty obvious just looking at the hotspot on a white wall with the light sitting still. Covering individual emitters with your hand will also help show it if only one is actually affected. The welding glass technique sounds like it would make it easier to see but I had a really hard time noticing it when directly looking into the emitters. Best way to check is just put the light on hitting a wall in your peripheral vision and do something else you should notice the stepping/flickering pretty easily like that.
It could well be that my extra Vcc wiring between the 13A and the 7135s is what is exacerbating the issues. Or maybe it really is my particular MCU board which is a dud. Gotta eliminate at least the dud board/chip theory first.
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So I just ran another test on the MCU-less driver. This time with a low low input voltage of 7.7v. According to my original resistance loss predictions I should be just out of regulation at this stage.
The results are just lovely, so smoooth!
The faded graph in comparison is the dismally awful performance of the MCU controlled driver with an input voltage of 8.1v! so this isn’t even a like for like comparison. Seeing how badly the light did at this voltage I didn’t bother testing any further down. The only benefit of the extra 0.4v overhead is right at the beginning when driver current and total output is higher, then it just proceeds to wobble and flicker it’s way downwards :~
Also interesting to see is how (I assume) the Vf of the LEDs or perhaps (less likely) the dropout of the 7135s seems to reduce a fair bit over the course of the test, resulting in a drive current that actually rises from 15.3A at turn-on to 16.4A at the end of the test. That may actually go some way to combating the output decline due to voltage sag of the batteries in this voltage range. Very interesting indeed.
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Seeing these graphs just verifies why I was so delighted with the performance of the light last night. It just runs so smooth and output seems so stable compared to before, even when running the packs right down. I never really felt the urgh to top them back up, this thing just keeps on chucking the lumens! :bigsmile: