ASTROLUX MF01 Mini - common issues thread

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Dr.Phillip
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ASTROLUX MF01 Mini - common issues thread

Hi everyone I want to post some info here about the most common issues with these MINIs and some solutions how to fix them.

1. Incorrect Voltage measurement and LVP kicking in

I asked Lexel about the problems with voltage measurement (since he is the one who designed the board) and he was very kind in walking me through the problem and showing me a solution. Some of these MINIs measure the voltage bang on, some measure up to 0.4V less. If they measure the voltage to be 0.3V less than it really is, the low voltage protection will kick in 0.3V sooner and turn off the light. This is caused by the fact that the manofacturer has changed some components in Lexels original design for cheaper alternatives: mosfet, inductor and very likely a diode (Lexel wasnt sure from the picture about the diode). The easiest way to correct this is to flash the flashlight. Manual for doing so can be found here:

http://budgetlightforum.com/node/68915

You will need to do following changes to the code:

_in the hwdef of the Anduril files you needx to adjust this code

// average drop across diode on this hardware
#ifndef VOLTAGE_FUDGE_FACTOR
#define VOLTAGE_FUDGE_FACTOR 5 // add 0.25V
#endif_

each +1 adds 0.05V

I asked ToyKeeper if she plans on adding a feature that would allow voltage calibration by clicking in the menu. She told me its not realistic at the moment. As is the Anduril code barly fits onto the chip most flashlights use. Thats why there is eather check version or muggle mode option but not both. Some flashlight like emisar have switcher for larger chips, but most havent.

2. Flashlight throttling down after few seconds from max ramp

These lights have a tendency to throttle down from max ramp after 20-30sec to about half the visible intensity. This doesnt seam to happen as fast in turbo mode when the lights get much hotter. I asked Lexel about it and he gave me this explanation (I copied only the most important parts):

_It’s not a problem it’s a sign that the user didn’t calibrate the temperature setting.
Any Bistro 3 channel driver has this behavior and no one ever complained about it.
It’s a known fact that FET+n+1 drivers heat more in regulated mode than while FET only active (smaller drivers are always more affected than big ones).
FET+1 drivers have only a fraction of heat on driver compared to a full bank of AMCs, also a 7 LED light has low LED voltage
You can simply eliminate this by flashing a firmware not using the AMC bank stepping back to FET+1 2 channels.
Generally a setting of like 45°C is way too low with new temperature code, I usually use 55 or 60°C (LiPo is 70°C upper limit)._

Easiest solution here is to calibrate the light to the correct room temperature and set the temperature limit higher. Let it cool down to room temperature (like about 30min) and calibrate the temperature to the actual flashlight/room temperature. Than set the temperature limit to a higher value like 60C (max 70C). As I understood this (please correct me if I am wrong) some components on the driver get very hot during voltage/current regulation in ramping and on max ramp they get so hot that they cause the driver to lower output power. This effect is a bit more noticable on this light because is has very small and a bit packed driver board (they had to fit those components in somehow).

EDIT 30.11.2019:

User man of light designed a great little copper insert that replaces the original plastic driver cover and creates a thermal bridge between the AMCs and flashlight body. This copper MOD will greatly increase the time before the light starts throttling down in ramping once you set ramp level. Here is a link to his project, its simple jet very clever MOD and he is trying to secure a small batch of these custom made for us, go check his thread for more info on this project, prices etc. Link:

http://budgetlightforum.com/node/70329

p.s. I am very gratefull to Lexel and Toykeeper for entertaining my silly question (especially to Lexel who walked me through details).

Edited by: Dr.Phillip on 11/30/2019 - 18:02
eneoros
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Hi, what i can say is that i calibrated the flashlight very correctly,i set te temperature limit to 60 and even more degrees Celsius and the stepping down is present no matter what. But i noticed that when i ramp a few times up again it strats to hold the max ramp longer and eventually it stays there for a few minutes. Another thing i noticed at the same lumen level (i tested with 1800lm) with fresh battery 4.2v it strats to step-down after 5 to 10 seconds, but with little bit drained battery 3.8V and lower it holds those 1800lm for a few minutes. Another thing i noticed that when the flashlight hold the max ramp when i touch it it steps down a bit and when i leave it it stay on that new level (it is exactly opposite of my other lights in wich the touch cool them down and increase the output). At all very strange behaviour,so the explanation about incorrect tepm set isn’t the case here, it is something else.

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Hi eneorors. The way I understood it is this: the chips responsible for ramping drop a lot of power during ramping. At max ramp they should drop the most power. They get very hot very quickly. There are several of them on the driver and they are very close together on a small board. This heat doesnt get transfered to the flashlight body as well as the heat from LED emitters. They do descipate the heat slowly, but there is really nothing we can do about it(I dont think there is termal paste between them and flashlight body.

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But this isn’t happening only in max ramp it happens in 1000lm too, it rapidly step down to about 500lm.To me it doesn’t seem that heath is the trigger.

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Thank you Dr.Phillip for creating this thread and collecting all the Information to the mentioned issues of the MF01 mini. Also thanks to ToyKeeper & Lexel for the analyses and Infos.

To the 2nd Point (stepping down after few seconds): Its not only from max ramp, it steps down from any output level, from about 500 – 2000 lm, for example if you just switch on in last memory mode of about 1000 Lm. As already explained by Lexel, if the FET is not active, the AMCs are getting to hot very fast and therefore is this step down.

Quote:
Easiest solution here is to calibrate the light to the correct room temperature and set the temperature limit higher. Let it cool down to room temperature (like about 30min) and calibrate the temperature to the actual flashlight/room temperature. Than set the temperature limit to a higher value like 60C (max 70C).

I’ve already calibrated the thermal setting exactly this way , and anyway after switching the light on in a output level of about 1000 Lm it takes 10-15sec in my case till the step down begins. It goes quite quick to abot 500 Lm.

I started thinking about a mod to heatsink the AMCs to the host. Therefore I would replace the plastic cover of the driver board by a copper manufactured ones wich would have a good contact to the AMCs with thermal grease. Also the contact to the driver pcb (GND surface) and the host should be good to transfer the heat. Very important would be a safe insulation to the positive pole and the other parts of the driver boards, to avoid short circuits and conductive contacts. Maybe Lexel could estimate whether such a modification would be worthwhile to stop the step down or significantly improve.

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Dr.Phillip wrote:
Hi eneorors. The way I understood it is this: the chips responsible for ramping drop a lot of power during ramping.

Let me try to explain this part. The chips you are refering to are AMC7135 current regulators. These accept voltages from around 2.7v to 6v and what they do is only allow around 0.35A (350mA) to pass through them. The mini has 3 channels controlled by the MCU. Channel 1 uses a single 7135 chip as seen in the pic below.

This is pretty low current so it doesn’t produce much heat and the brightness range is small. It makes for a nice moonlight level and up to maybe 150 lumen.

Now channel 2 uses the 6 chips plus the 1st one. So now you have 7 chips that allow up to (.35 × 7) 2.45A. This is what the top of the ramp is set to. So all 7 chips do produce some heat, but you can see the ground tab is soldered to the outer copper ring and that is pressed against the battery tube. That is your heat path (red arrows). This looks pretty decent. Actually, the battery tube does not contact the driver so that heat is not being drawn away.

The temperature sensor is built into the MCU on the other side of the driver board as seen below.

The way heat gets to the MCU is through the 8 metal legs.

Dr.Phillip wrote:

At max ramp they should drop the most power. They get very hot very quickly. There are several of them on the driver and they are very close together on a small board. This heat doesnt get transfered to the flashlight body as well as the heat from LED emitters. They do disipate the heat slowly, but there is really nothing we can do about it (I dont think there is thermal paste between them and flashlight body).

There is definitely no thermal paste on the 7135 chips as they are soldered.

On Turbo, all 7 chips are not used and all the power goes through the FET. You can see there are a lot of vias around it to spread the heat to the other side of the driver.

I really don’t know if this quick step down from the top of the ramp is a standard problem of the 7135 chips getting hot and heating the MCU much quicker than the body or if something strange is going on in the software.

I believe the 7135 chips may not have to shed as much heat at lower voltages. If so, then that might explain why the lower voltage allows for longer runtime before stepping down. Maybe there is some unknown thermal path between the 7135 chips and the MCU that is causing the problem and this mystery path is not between the FET and the MCU which is why Turbo does not step down early.

IDK, it’s a bit of a mystery.

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It sounds like this step down should be noticeable but I have not noticed this step down. I will look again tonight. I have not calibrated my light at all. 

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Thank you JasonWW for extending and correcting my somewhat not exact answear. Now we have a full explanation.

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Dr.Phillip wrote:
Thank you JasonWW for extending and correcting my somewhat not exact answear. Now we have a full explanation.

The mystery is still afoot. Lol

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Interesting topic. So which type of driver will run cooler at let’s say 500 lumen, a FET+7+1, FET+1 or linear-FET driver?

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Ryzbor wrote:
Interesting topic. So which type of driver will run cooler at let’s say 500 lumen, a FET+7+1, FET+1 or linear-FET driver?

Do you mean in a MF01 mini?

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I’ll assume you mean on the MF01 mini. Man, that’s a tricky question with a lot of parts. I can only answer parts of it.

First we need to figure out how much amperage is needed to put out 500 lumen. Let’s make an educated guess based on the 6500K SST-20 Djozz tested and say 1.5A.

With the FET+6+1 (mini driver design), the FET does not come into play. You are using the 7 total 7135 chips (2.45A) with maybe a duty cycle of 61% (I don’t know if the duty cycle is directly related to output percentage, but let’s say it is).

With the FET+1 we are using the single 7135 chip at 100% duty cycle and the FET at maybe a 12% duty cycle (based on 100% drawing 20A).

I’m not sure what you mean by a linear-FET driver. Sorry

So now we would need to run them and use a thermal camera or temp probe to see which gets hotter. For this, I have no idea. People rarely talk about driver heat because it’s usually a non issue.

We would need to talk to someone like Lexel who makes drivers and has a thermal camera. Maybe Texas_Ace, Toykeeper or Tom E know about the heat production of these components at these operating levels?

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Let me see if’n I understand how the three channels are set up.

Channel One is a single 7135 (so, about 0.35A max).
Channel Two is seven 7135s (about 2.45A).
Channel Three is…what? Direct-Drive FET? Or what? Max (battery-dependent) current is?

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Ryzbor wrote:
Interesting topic. So which type of driver will run cooler at let’s say 500 lumen, a FET+7+1, FET+1 or linear-FET driver?

At that level you won’t really have an issue with heat from the driver in either setup. As long as the driver has some kind of contact with the body of the light it should be fine.

That said, a PWM FET will always run cooler then a 7135 or linear setup. Properly setup they will produce virtually no heat.

You can calculate the heat from the linear setups (this includes 7135’s) but it boils down to that fact that the total heat they need to burn off to maintain regulation will be the same no matter how you do it, 7135 or linear FET.

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riffraff wrote:
Let me see if’n I understand how the three channels are set up.

Channel One is a single 7135 (so, about 0.35A max). Correct
Channel Two is seven 7135s (about 2.45A).
Yes, but technically Ch 2 is 6 7135 chips plus Ch 1 running at 100%. So it’s kind of like 7 total chips, but it depends on the software. Narsil and Anduril keep Ch 1 at 100% to smooth the transition into Ch 2. This prevents a noticable tint shift. I said 7 chips to keep it simple.
Channel Three is Direct-Drive FET? Max (battery-dependent) current is? Yes, I remember some amp draw tests between 16A and 20A. It depends on the emitter and battery

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Texas_Ace wrote:
Ryzbor wrote:
Interesting topic. So which type of driver will run cooler at let’s say 500 lumen, a FET+7+1, FET+1 or linear-FET driver?

At that level you won’t really have an issue with heat from the driver in either setup. As long as the driver has some kind of contact with the body of the light it should be fine.

That said, a PWM FET will always run cooler then a 7135 or linear setup. Properly setup they will produce virtually no heat.

You can calculate the heat from the linear setups (this includes 7135’s) but it boils down to that fact that the total heat they need to burn off to maintain regulation will be the same no matter how you do it, 7135 or linear FET.


So does the duty cycle of a single 7135 chip have any effect on the heat it puts out?

I was thinking the FET didn’t generate much heat, but we’ve seen some cheap ones burn up with high amperage running 100%. So would the heat it puts out be dependent on duty cycle?

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JasonWW wrote:
Texas_Ace wrote:
Ryzbor wrote:
Interesting topic. So which type of driver will run cooler at let’s say 500 lumen, a FET+7+1, FET+1 or linear-FET driver?

At that level you won’t really have an issue with heat from the driver in either setup. As long as the driver has some kind of contact with the body of the light it should be fine.

That said, a PWM FET will always run cooler then a 7135 or linear setup. Properly setup they will produce virtually no heat.

You can calculate the heat from the linear setups (this includes 7135’s) but it boils down to that fact that the total heat they need to burn off to maintain regulation will be the same no matter how you do it, 7135 or linear FET.


So does the duty cycle of a single 7135 chip have any effect on the heat it puts out?

I was thinking the FET didn’t generate much heat, but we’ve seen some cheap ones burn up with high amperage running 100%. So would the heat it puts out be dependent on duty cycle?

In the case of the 7135’s the duty cycle will increase the heat simply because you are also increasing the current / power.

With the FET’s, a good one should have basically no heat at normal power levels (yes, it technically does produce some heat as all FET’s have some resistance but just not enough to really matter much for anyone asking a question like this). On hot rods where we are driving 10-20A+, then the FET can produce some heat if it is high resistance and even die. The only cases that come to mind of the FET dying were at currents of ~20A+.

Although this is more a case of simply pushing the FET past it’s design specs then it getting too hot directly.

The duty on the FET will increase the heat since it also increases the total power / current but technically it will actually get a bit more efficient when you reach turbo 100% duty as you no longer have the switching losses. Once again though this is a case of if you have to ask, then you most likely don’t need to worry about this as it will only matter in fringe cases.

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Quick question, what exactly is a linear-Fet driver? Is that a thing?

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JasonWW wrote:
Quick question, what exactly is a linear-Fet driver? Is that a thing?

I don’t know it exactly as well but I found this:

High efficiency LED driver. All modes (except moon) are implemented without PWM , linearly, using a current source based on a MOSFET transistor, which in practice means 1.5-2x longer work time at low brightness levels compared to classic PWM drivers keying the AMC7135 current sources or transistor.

The controller has a turbo mode (current 8A), about 3200lm for 4x XP-L, implemented by a MOSFET transistor, with hardware stabilization of the upper current value.

Parameters:
• linear5A current source implemented on MOSFET RDSon 0.95 mΩ transistor controlled from ATtiny85V with feedback
• modes (brightness levels) implemented without PWM, with maximum LED efficiency
• diameter 17mm – flashlight standard
• supply voltage range 2.8-4.5V
• power supply: 1× 18650 Li-ion cell, preferably without protection
• maximum LED current 5A, in turbo mode 8A (limited by the capacity and battery charge level)
• full current stabilization at Vf LED + 0.1V supply voltage, with the latest brand cells to be used 80-85% Li-ion capacity
• no PWM , flicker, noiseless operation
• total efficiency 2.8-4.5V power range is over 90%

and

Barkuti wrote:

Both Led4Power and the latest drivers available at the Convoy store use MOSFETs as linear regulators. They use their microcontroller to monitor the voltage drop at a sense resistor, and according to this they precisely tune the MOSFET gate voltage for it to exactly drop the required voltage delta. This means the dissipated power at the MOSFET is voltage differential times current, being this the main driver hurdle (dissipated power in MOSFET and driver, nothing to do with amps rating here). (̮

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JasonWW wrote:
riffraff wrote:
Let me see if’n I understand how the three channels are set up.

Channel One is a single 7135 (so, about 0.35A max). Correct
Channel Two is seven 7135s (about 2.45A).
Yes, but technically Ch 2 is 6 7135 chips plus Ch 1 running at 100%. So it’s kind of like 7 total chips, but it depends on the software. Narsil and Anduril keep Ch 1 at 100% to smooth the transition into Ch 2. This prevents a noticable tint shift. I said 7 chips to keep it simple.
Channel Three is Direct-Drive FET? Max (battery-dependent) current is? Yes, I remember some amp draw tests between 16A and 20A. It depends on the emitter and battery

Thanks for that. It’s all much clearer to me now. Beer

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JasonWW wrote:
Quick question, what exactly is a linear-Fet driver? Is that a thing?

As posted above it is the same style that LED4Power uses and the Texas Commander was designed around. Basically it uses the FET to do what the 7135’s do.

The issue is that the FET is not really designed for this so it is much harder to deal with the heat it produces since it does not have a dedicated thermal pad like the 7135.

Thats why I suggested putting the FET on the mcpcb to give it a better heat path, which ended up working out quite well from what I have seen from LED4Power.

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circling back around, i’ve found on my full copper version that i can get it to stay at turbo until i can barely hold the light by setting the room temp at 14 and the throttle at 60

so it’ll definitely do it at least in ramped mode

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So you say that in copper version there isn’t the step-down problem in ramping mode. What emiter type is you unit. I think i saw someone else saying that the copper head or all copper doesn’t do that but i am not sure, can anyone confirm if those versions are free of the bug present in the coloured ones.

Turby3Pots wrote:
circling back around, i’ve found on my full copper version that i can get it to stay at turbo until i can barely hold the light by setting the room temp at 14 and the throttle at 60

so it’ll definitely do it at least in ramped mode

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eneoros wrote:
So you say that in copper version there isn’t the step-down problem in ramping mode. What emiter type is you unit. I think i saw someone else saying that the copper head or all copper doesn’t do that but i am not sure, can anyone confirm if those versions are free of the bug present in the coloured ones.

I never quite fully understood the bug to begin with, but my full copper MF01S mini operates approximately identically to my MF01S; it ramps down once hot, but at an imperceptible speed, and seems appropriate. Only after a minute and being very hot will you notice that it must have throttled; a double click back to turbo will confirm it.

It will get so hot you can’t hold it. It does appear to get brighter once it’s cooled off a bit. This on a black and red Shockli 5500 26650

I did reset the resting temperature (found it way too high – like 33deg C at room temp) and set the throttle to 60

I don’t think there ever was a bug but of course this is merely conjecture as I don’t have any other mini other than this one full copper.

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Last friday I’ve modded my MF01 mini, as mentioned in post #5, the result is very satisfying, no throtteling down any more in any ramp level (also top ramp) till the host (body) of the light reaches the setted max. temperatur. On max ramp 130 (20 clicks from turbo) it takes about 3 Minutes till it reach the max temp (60°C) and begin slowly to step down.
A level around 1200lm can be kept constantly (@amb t20°C), this makes the light very useble now.

Background of the mod idea:
After reading a comment form Lexel on TLF regarding the heating of the AMCs when not in turbo mode and the bad thermal contact of the driver pcb to the host, it was clear to me why there is such a throttling down after few seconds from max ramp.
So, if the light is operating not in full FET mode (turbo), the AMCs becomes hot very quickly, this heats up the whole driver pcb where the mcu with the temp sensor is located on the backside. Therefore the quick step down in max ramp, when the host is not even at 45°C, the driver pcb with the mcu is already at 60°C.

I replaced this plastic cover:

by one out of aluminum that looks like this:

Here is a link to a drawing, in case someone is intrested: https://imgur.com/jHjj1Xz

and contacted the green marked surfaces with thermal paste:

The Design was very accurately defined, so after fixing this heat sinking cover plate, the gap to the AMCs is 0,1 mm, there is no mechanically contact to the parts of the driver board except the big outer GND-Surface.

Afterwards it looked like this, additionally I used a thin plastic washer for isolating the aluminum cover to the battery plus pole and used a magnet:

After this mod, the AMCs and the GND surface of the driver pcb is very well contacted to transfer the heat to the flashlight body. The Battery tube is now also directly connected to this heat sinking cover plate if it’s screwed together with the head, this was not the case with the plastic cover.

This mod would be even better if the heats sinking cover plate where out of copper and CNC-machined precisely like this. Only the costs are relatively high for a single production.

Here is a link to a drawing, in case someone is intrested: https://imgur.com/dyBRHRq

I hope this mod info is interesting for some and that I could explain it understandably.

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Okay, now I see. There is a plastic cover that prevents the battery tube end from pressing down on the driver (like I was thinking).

So does the battery tube screw down into those two screws?

What is the function of this plastic cover?

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Quote:
So does the battery tube screw down into those two screws?

Not quite, it remains a small distance of about 0.5 mm. The screws are sunk in the plate a bit, and the upper surface of the plastic cap has still a gap of 0,3 mm to the the battery tube end. In my heatsink plate design I closed this gap, so there is a proper direct contact from tube end to the plate on the whole circumference of the tube.

Quote:
What is the function of this plastic cover?

It protects the driver pcb from direct contact with the battery, fingers, dust or other objects. It holds the screws for fixing the pcb. That’s it.

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Nice mod, that should be made standard in the next run of lights honestly.

I bet you could sell some of those to other BLF members as well.

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JasonWW wrote:

So all 7 chips do produce some heat, but you can see the ground tab is soldered to the outer copper ring and that is pressed against the battery tube. That is your heat path (red arrows). This looks pretty decent.


My earlier post.

So there is nothing metal that comes into contact with that copper trace the red arrows are pointing to?

I guess there is only a certain percent of vias to carry the heat to the other side of the driver where it touches the metal. Now everything makes sense.

Texas Ace Lumen Tube calibrated with Maukka lights

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JasonWW
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I think a quick fix could be to just add a metal ring, aluminum, copper, etc…, just to connect the edge of the driver to the battery tube. Give the heat some mass to soak into so the MCU doesn’t get too hot, too quick. Touching the top of the 7135 chips may not be necessary.

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man of light
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JasonWW wrote:
I think a quick fix could be to just add a metal ring, aluminum, copper, etc…, just to connect the edge of the driver to the battery tube. Give the heat some mass to soak into so the MCU doesn’t get too hot, too quick. Touching the top of the 7135 chips may not be necessary.

Yes, there will be definitely a positive effect. Was also one of my first thoughts. I tested it with one aluminum ring without the two screws and without thermal paste. The ring was 3.7 mm high, so that there was proper contact to the battery tube. The results where better but I was not statisfied yet, step down on max ramp was around 1 minute. Ich thought there is not enough mass for the heat and designed the described plate.
Sure, a copper ring (Outer-Ø 29,8mm, Inner-Ø23,5mm, height 3,7 – 4,0 mm) will show better results with some thermal paste. But I would recommend to add two bores for the two screws to fix the driver and the ring.
If there is interest, I could provide a design proposal with a drawing for such a ring, for somebody who want to try it.

Texas_Ace wrote:
Nice mod, that should be made standard in the next run of lights honestly.

I bet you could sell some of those to other BLF members as well.

Unfortunately, I have no possibility of producing such parts, I’m depending on others who have such toolings.
I can provide the 3D-CAD data and drawings, maybe somebody is able to manufacture a small batch for a reasonable price.

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