Gang,

My weather is very hot at 34C and it can actually make the C4 goes offline to my laptop
C4 is inside the car, so no airflow and one side of its alu body rest on car leather seat, less cooling can happen.

Today I decided to tear open the unit to try to make cooling system.

For the itchy eyes, here come :



So I drilled holes of approx 12mm diameter, approx.







I make opening at the end side where there is no connector. That funny zigzag thing is the wifi antena.



BELOW : So the whole alu cocoon body , is not actually touching heat sink at one of the hotter PCB board, but it does help to cool the components....but poor.
When in use like 20 minutes, the alu cocoon body of C4 can hit 40C. That means the hot components would be 60ish Celsius plus.










Aboe. The right side image, that PCB board is the hotter one among the 2.



I am experimenting one side of the holes getting DIY filter membrane




Basically, I will later get a laptop vacuum/suction type cooling module like below :





So today I tested airflow potential. I use my charger fan and I practically kiss the end of C4 to the fan middle part, which means it is not at the best air suction flow of a fan.





Result is not bad... I am happy. Approx 20ish minutes the C4 is no more hot at the aluminum cocoon body and internal components is cooler by a lot.

Below is the non filtered holes. Internal components read as 36C ( the MAX ). Car interior ambient was 32C.




Where the fan opening is, below : So we are seeing PCB board stack.


Viewing angle, approx





2 PCB board stack, zoomed.






================================================== ================================================== =====================================


NOW, C4 10 minutes operational, no fan assist.








Where the fan opening is, below : So we are seeing PCB board stack.



PCB board stack, zoomed




PCB board stack, zoomed





Approx 10C hotter component level for a non-fan assist set up in just 10 minutes. Damn !!!

End of report.

 

The C4 went offline due to overheating yesterday when I was troubleshooting HVAC issue for a friend's AMG CLS63 5.5L M157.981 engine. 2011 built. W218.374
Let it cool down for 20 minutes and then run it again, all good.
I forgot to make it stand up, instead its bottom side ( no display side ) was flat on the seat, so less heat transfer possible by the aluminum cocoon body....yep, such simple placement matters.




This is at my regular indie workshop.
I told him, if he gets a tough HVAC problem on MB and I know the owner directly or indirectly, let me troubleshoot for practice sake., FOC.

 

Surya, sorry to read this happen to your new gear. This enclosure unit definitely need active venting with a ball-bearing fan. Normally cold air is forced in to prevent fan from harsher condition of pulling hot air out.


+ not real hot
O Needs a heatsink !?!
X Mild heat profile
V: already cooled
We see opportunities for improvement if heat-crash problem continues.

Keep in mind the die size under the chip epixy casing is super tinny.... like 4 Square millimeters or less !
​​​​​​Meaning the heatsink full coverage all the way to the edge is useless.
Only center spot has the hot silicon die.


Voltage regulator feeds nearby processor.... HOT!

Already we see that couple heatsinks are in use for what must be the main processors.

Next time around you can increase the heat dissipation of more chips.
​​​​​
In addition, you may want to inspect the two existing heatsinks... upgrade them to taller fins.

Also double check a common mistake: different chip heights under the long central heatsink unit... poor contact means poor dissipation. Check the thermal paste or a pad is in use under there!


sample heatsink styles
There are many sizes available to fit form & functions. Usually relies on self adhesive stickers to pass all the heat through.

Link to eBay sample listing.


Lastly whatever power supply unit is feeding that C4-Box may needs cooling to remain stable.

 

For thermal paste, I have used Artic MX-4 and MX-5 (last one) with lot of success. I repaste about 15 different laptops where the old paste was basically junk. The CPU immediately cooled down using their standard fans.


On the active cooling (with fans), I am with @CaliBenzDriver , but be careful not to increase the new fan flow too much either. There is a subtle balance between fin geometry/material used and the flow around it. Infinite flow is not the best and it becomes noisy at some point anyways.

Also, timing is an issue. The longer you wait (at least you already started), and the more you use it (enjoy I mean) the faster the long-term damage to the board and components.

 

Thank you gents......
The aluminum cocoon shell is already so tight space. So no more room to add taller heat sink.
The only way for now is to use that laptop vacuum style fan for forced suction and see how the temperatures are.

 

Surya, you can always wrap it around a cold plate

 

... or a Peltier cooler

 

OR MOVE TO ICELANDIC AREA

+++++
> Seriously...:
Where does the POWER SUPPLIED to this C4-Box come from...reliable?

---+++++
YUM YUM YUM GUINESS ...
it's said that factory is bigger than 10 city blocks - Big tourist attraction to taste the real IRISH GUINNESS STOUT.
👍


Here Surya: I've found what I was looking for

CIDER is an old British classic... Healthy hard drinkable



local favorite "hard Apple CIDER", low-sugar formula
From one of the Silicon Valley cities of San Jose California.

 

Aha............good u found the Cider.

 

1+ hour non stop use on a hot day today withe 32C ambient temp approx.
This unit is a blower type fan, like our HVAC blower. This kind of fan has very strong suction ( high static pressure ), but airflow volume 30% or less than simple axial PC fan which has very poor static pressure.


Xentry C4 clone on the W218 CLS63 AMG today, for HVAC fun work.




I am very happy and impressed with this fan. US$20 only. 13 speed level.


So I rigged a mounting system for fan to C4, crude but works well. Under the alu tape, lots of double side tape... LOL.
Cloth filter can stick due to its suction, awesome blower type fan indeed.






I keep bottom holes non-filtered and added 10mm HVAC foam pad on C4 under body, so now I can sit it flat on those 6 holes yet airflow still possible because of the gap.
No need filter is because the holes would be facing down, so dirt can't enter by fighting gravity. Although suction is strong it can't suck dirt from 10mm upwards.



Mission accomplished

 

By brain fart moment, I left my C4 plugged-IN at my car for 3-4 hours, and the extra forced cooling fan was NOT on....interior door closed.
I just completed some test for fun and thought that I already un-plugged the C4 from OBD2 port
Ambient temp was 32C............... by the time I found out and tried to cool it down, it was very hot the whole body.

Trying to cool it down using the forced cooled fan, the discharge air alone was 43C, never I had air this hot.....



And then the C4 software seems corrupted due to heat....... can not connect to my car or my laptop.







Looks as though as working.............as though as .......but it was not




No burnt smell or anything...............







No other choice but need to order new one .....


Tropical country and its issues on accelerated thermal damage on components.................


End of Sad Report.

 

I looked over these circuit boards for ya.... nothing that stands out as toasted

 

Yep........ overheating fatigue I guess... maybe the memory chip keeping the software was not robust enough for what I believe could be 65C or hotter semiconductor
actual temperatures.

If this is a genuine MB unit, I would think it will be more robust heat tolerant wise, because I never seen cooled multiplexer like mine with extra fan

I tested its power consumption this morning, it is only 6.xx watts idling, maybe a bit more when in proper communication with car and laptop.

 

Idling modern electronic uses low power like our car when it's locked to low power/sleep.
Under computing power the heat from multiple CPU & misc chips must be removed outside so it doesn't accumulate up inside.

Fun: guess what's not running by looking at low IR temperature....

Now that you have a "fancy door-stop" you can do a post mortem review.
Lift up the various heatsinks and see how dryed out or not the heatsink paste is doing.

 

Too lazy me, to do that autopsy
Its known already, heat is its weakness.

 

CTEK shares the same issue of having enclosed heatsink... heat can hardly escape outside.

Swiss cheese technology to the rescue...


vent through drillings


air can flow through

The pattern of holes match the internals components.

NOT for Outdoor use nor watertight but much cooler use.

 

For my tropical country........... FORCED FAN is the only Friend ...

See Ctek and Genius 5 heat signature....... very hot.

https://mbworld.org/forums/e-class-w...​​









.

 

These CTEK + NOCO compact chargers have heatsinks enclosed inside sealed plastic case.

There is very little heat exchange out through the plastic. It is an insulator that keeps heat inside.

I thought I would experiment bringing air flow to the metal heatsink:

• Heat exchange is a slow process....
• Natural air flow moves slowly
• Swiss-cheese vents help out ok!
• Forced air flow speeds up cooling

I bet NOCO has an enclosed heatsink similar to CTEK. These small chargers have limited power handling, perfect for float charging.

I share that here because overheated "C4 interface" died of accumulated heat not removed. Great electronic device built with a fatal heat issue.

> What are you going to do to custom cool your next C4 unit ??

 

The very same laptop cooling fan I am using today. Its been great, as long as it is turned ON the moment I plug in the OBD2 port connector to car.
It can maintain maximum +2C hotter exhaust air sucked out of the C4 unit, over the ambient temp...which is VERY VERY good.
Basically the C4 can run 24 hours and wont overheat.

Since the fan is USB 5V type power, I need a power bank or car cigarette lighter with USB 5V adapter, but the problem with the 5V USB fan I am using is,
everytime I loose power from cigarette USB 5V adapter ........due to Ignition Cycling ON-OFF-ON ( compression test ), I have to press again the fan activation button.
Therefore I use powerbank instead and not car cigarette USB 5V adapter, to remove the risk of having to keep turning ON the fan manually in relation to Ignition Cycling.
Note : Cigg socket is under accesories Ignition Key position 1, so when I am at ignition key position 0, cigg socket lost power.


Soon I will change the way I will power the cooling fan.
I will get OBD2 splitter wire like below :



The MALE one goes to the car's OBD2 port.
The 2 FEMALE , one for C4 and one for power port of 12V to 5V USB power supply for the fan. OBD2 has 5 amps fuse for 12V power and is constant Circuit 30 power, always hot.

All I need to do Macgyver this 12V to 5V USB cigg adapter on the same OBD2 cable C4 uses .....and I then have permanent power to the fan, as long as I start the fan the moment OBD2 connector get married to the car.
Or I can tear-down existing C4 OBD2 cable core and steal the ground and +12V from it, without needing OBD2 splitter cable. The new C4 will come with its own new wire set OBD2 and some other older MB connectors.

 

Stealing +12V and ground from existing C4 OBD2 wire assy




Testing 5 watts bulb load, to find which wires carry the current.





Can't open the connectors, both round one to C4 or the OBD2 version to the car.

So minor operation needed.



.




.





============


Wire tracer tool useless for such close up wire bundle.




Patience and logic works better.
Negative should be black wire, positive should be red wire........ and use current clamp. So no need to needle pierce each suspect wire and wound the PCV jacket.

POSITIVE



POSITIVE



NEGATIVE



RE-CONFIRMATION, should be zero amp if both Negative and Positive read together... DONE.



===================


Heat & load testing the 12V to 5V USB cigg adapter. This one from my Viofo dashcam, so it can do 1 amp non stop easy.



Maximum fan speed is 13. What a bad luck number ...LOL



Max only 3.37 watts at 13 volts for the cooling fan, including power loss to conversion of 12V to 5V DC of the cigg adapter.




==================


Crude soldering.........




Tested OK




===============


Now wire tapping.....


.



.



.



.

3M Electrical Taped, 2 layers.



Place back lost ALU foil jacket.



3M taped again



Tesa taped







Heat and load test. Idling only C4 is 6.x watts at 13 volts. With cooling fan, total 10.x watts.



2 hours heat and load test on the now jacketed 12V to 5V cigg adapter. Still very cool. Was 3:36 PM start and ending 5:37 PM.



Very cool, both the idling C4 and the 12V to 5V cigg adapter which is only 4C hotter at 32C than ambient 28C.



The new C4 hopefully end of April should arrive in Jakarta....

Till end of April......... I will be back.