AMC chips are not as rigid as everyone used to think. They start dimm or turn off after overheat. Some of them a better than others, not sure if any brand ones are still available. Those that can be found from ali are the worth.
(Most of you know - Im not a fan of 10-sec output tests, and one of the reasons - they never show real usage issues. You wont recognize that some of AMCs have turned off with 10-sec hotrod. Use power supply and 1-hour test to see this).
They can transfer heat to the central pad and even 1V difference between cell voltage and Vf will cause 0.35W heat that does not seem too much for this way. Yes then they heat up drivers outer ring.
Next thermal way is too hard for analyzing. Copper coated through holes on the outer edge are possibly to small to transfer heat to another pcb side. I would guess chips №5 and №6 are heating mcu from the backside.
Once again, see #1 - AMC chip can lower output by themself, without program step-down.
We are not able to set different temperature range for components mounted on one pcb inside enclosed aluminium case. With different mode sequence you will get different parts and components overheated (i.e. one part could heat up other after one situation and vice versa in different situation).
To make this thermal exchange more stable (dont forget that most components have properties that change with temperature raise), we need to limit temperature delta. Inside one pcb or whole host. Using thicker copper layer, alu core based pcb, thermal pads or grease, extra parts to transfer heat to the host. Using any sort of thermal materials between pcb shelf and driver components may looks strange - in first suppose led will heat up driver and not vice versa. But in real life, you wont be able to cover any component with “thermal shield” and leave it colder than whole host - this is not possible (unless you are making 10-sec test). And temperatures mentioned in this thread can rarely cause any issues - usually there is one or several true overheated (over 85 C) components on driver board.
Now few questions for MF01 mini users:
Have you tried using thermal pads between MCU and shelf?
Have you tried more straight solutions? Simple ring that faces driver outer ring with one side and tube with other side? (Not sure this is possible, probably they should be electrically isolated).
Kiriba assumption is correct, problem are badly placed (no 5 and 6,but possible only no 5) AMCs directly below MCU on the other PCB side. And if there are any GND vias under MCU which connect top and bottom GND area, it's a recipe for - measuring AMC chip temperature instead of driver board temperature. 0.35W of heat dissipated in single AMC is more than enough to cause false MCU OTP triggering if that AMC is in thermal contact with MCU. While AMCs are soldered to GND ring, that heat path is not as nearly as good as it intuitively looks - 35um thick copper trace has very limited "reach" after which it doesn't conduct heat better than FR4 core itself. So it's a basically PCB design flaw, but even with AMCs far away from MCU, they are still on same PCB, so problem would be not completely solved, but definitely reduced.
Removing AMC no5 and/or 6 would show if all this is correct (I don't own this light,but I suppose staciking them onto other AMCs is not possible due to height).
All drivers (linear,switching) generate heat, I noticed similar issue back in 2014 with now ancient LD-1 driver, mid. mode would trigger OTP while light is still cold, but high mode was fine.
That's why decided not to use internal MCU temp. sensor and use external NTC sensor on LED MCPCB, which is the simplest and best way for accurate light temperature measuring - all my MCPCBs have place for NTC and in case of 1S lights it needs only one additional 30AWG wire, I expected BLF drivers would switch to this logical step, but for some reason till this date no BLF drivers have NTC support.
To be "historically correct", putting FET on MCPCB predates texas commander thread (2017) and your suggestion couple years before, LD-1 "expander boards" and LD-M2 used that principle, and in LD-2 thread from 2015:
is description with measurements of LD-2 driver with only FET mounted on external MCPCB which shows how beneficial is to not have FET on driver PCB, so I had idea of mosled/mosX MCPCBs (mosled = mosfet + led) for quite some time in my head before actually making first mosled MCPCBs.
Hell man, those look amazing. Great design, now I am envious :D. Such an elegant and well executed solution. Texas_Ace is right, this should become standard in future lights. I would buy 5 of these if someone produced them. Or at least two for my sad copper and brass ones to give them that premium feel. How long did it take you from idea to fully functional prototype?
External temp sensors are definitely the way to go. Unfortunately a lot of BLF software (Anduril, NarsilM) are still tied to the Attiny85 chips. Toykeeper has been working on using Anduril with the attiny1634 MCU (as seen on the Emisar D4 v2). I have not looked into this MCU, but it does have a lot more input/outputs. Does anyone know if it supports an external temp sensor?
In total it took me 2 working days, with some waiting time for the prototype in between. For such a design i don’t need much to time, have some years of experience developing heat sinks and cooling solutions for electronic devices.
At the moment i’m in contact with some possible suppliers for a small batch of this heat sinking cover plates. They will be CNC-machined out of copper and a further improved design. No magnet needed at the positive pole, more efficient space usage.
Estimated price 10 - 15$ / pcs. depends on batch size. It’s clearly not an low budget mod and maybe not that interesting for many, but sure for some of us.
I think this can be done. If someone wanted to test the theory they would ditch the plastic cover, screw the driver down, remove these two 7135 chips and stack them on nearby ones. Then maybe use a magnet to move the battery away if you need more height.
I don’t have this light, so I cant try it out either.
How could Mateminco change the design to improve the light?
Ditch the screws and plastic cover and make the battery tube longer to press against the driver? I think the battery tube screwed down and pressing firmly into the driver should get some good heat transfer. Man of light says it extended top of ramp to about 1 minute. Would this mod be a good enough fix for Mateminco to do?
I also saw another design flaw that one of the purple leds on aux led board is too close to the main led and the optic sits right on it and crushed it.
Mine wasn’t too close - but putting it all back together after reflashing was a pain. I think I’ll replace the wires with longer ones and stuff them in the cavity next time.
I was wondering if any MF01 mini owners can say anything about the charging port cover. Is the cover useful and functional? Does it stay in place when carrying it around?
I once ordered an Astrolux S42 and the charging port cover was garbage. It just wouldn’t stay in place, felt foamy instead of solid soft rubber, and flopped around every which way. I ended up getting a refund and selling it on eBay but ever since then, I vowed to never purchase any Astrolux lights especially with built-in charging.
I got the S43 and that cover seems fine. It’s made of silicone I think.
Vowing to never by a brand based on one bad thing, sounds extreme. Like people vowing to never by a ford, because one broke down on them. No lights, or cars, are perfect.
