Mi4c Overheat hardmodding [passive cooling]: Graphite heat dissipation foil

[Danny94]

Hardmod level: easy - medium

Well finally i recieved the Graphite heat dissipation foil from Aliexpress, according to seller this foil has a thermal conductivity about 1800W/m.k (wich would be very nice, don't know how much it is in reality).
So the hardmod can begin ;D.

First of all i will probably answer your main question. Will this modding really help ?
Hmm ... i can't answer it... I made tests before and after and i could'nt realize much difference. But heat gets really transfered as you can see in the pictures later.
Maybe it needs more and accurate testing.

But if you expect much less overheating you schould'nt do that. Installing RR 5.8.0 helped me more.

If you wanna try it tough here comes my small guide (if not at least enjoy the pictures ;D):

Edit: GPS Signal isn't able to get a fix anymore. If you would do this tough you have to discover why. It looks like that the graphit foil disturbs the gps antenna, so you have to cut out a hole around the gps antenna.

First of all you have to remove the back cover, i did it with a guitar plectrum.

Then i searched for the heat source and noticed that there is a small passiv cooling already:

Red circle shows thermal paste wich get connected with the cpu. The piece behind the paste is a metal plate wich distribute the heat.

Made a benchmark and measured to show you:

Next i cut the Graphite foil in the right size and sticked it on the metal plate:

Sticked it over the power and volume buttons (yes buttons are still working withouth problems), added back case, and frame of case:

Now some testings how the heat get distributed:

At least i put the mi4c into a case (with some space behind for let the air cooling a little bit) for good looking:

Thats it. If you have some other tipps to hardmod the overheat or improve my modding just tell me.

 

[Pikachu8119]

Air has bad conductivity of heat, so high temperature will stay inside of your phone

Sent from my Mi-4c using XDA-Developers Legacy app

 

[Danny94]

@Pikachu8119
What do you mean with air.
Theoretically the Graphit foil (wich you can see outside of the back case) is connected to the cpu of the phone and transports the heat outside like i have written and shown in the pictures.

 

[Pikachu8119]

@Pikachu8119
What do you mean with air.
Theoretically the Graphit foil (wich you can see outside of the back case) is connected to the cpu of the phone and transports the heat outside like i have written and shown in the pictures.

By saying "At least i put the mi4c into a case (with some space behind for let the air cooling a little bit)" what did you mean?
Is it about the space between back cover and case?

Sent from my Mi-4c using XDA-Developers Legacy app

 

[Danny94]

@Pikachu8119
Ahh.

Well, that part mean the Graphite Foil should get cooled by air. Because [theoretically] if the foil has no space/air, sometime it reaches the same temperature as the phone and no heat could get transported anymore.. This way it just delay the overheat.
But if the air can cool down the foil a little bit it won´t never reach the same temperature =) (heat exchange).

 

[Pikachu8119]

@Pikachu8119
Ahh.

Well, that part mean the Graphite Foil should get cooled by air. Because [theoretically] if the foil has no space/air, sometime it reaches the same temperature as the phone and no heat could get transported anymore.. This way it just delay the overheat.
But if the air can cool down the foil a little bit it won´t never reach the same temperature =) (heat exchange).

"theoretically" air layer won't let the heat come out because of bad heat conductivity

Sent from my Mi-4c using XDA-Developers Legacy app

 

[Danny94]

@Pikachu8119
Does you mean the air between the outer case and the Graphite Foil ?
-> Of course it won´t take much heat, but better then nothing.

Each passive cooling system needs Air.

Same concept like there.
The heat got transfered from the cpu into this metal piece and the air around this piece got heated -> The air take the heat away.

 

[Pikachu8119]

@Pikachu8119
Does you mean the air between the outer case and the Graphite Foil ?
-> Of course it won´t take much heat, but better then nothing.

Each passive cooling system needs Air.

Same concept like there.
The heat got transfered from the cpu into this metal piece and the air around this piece got heated -> The air take the heat away.

Yeah, but each cooler has its fan and it's hermetically connected with processor by thermopaste

Sent from my Mi-4c using XDA-Developers Legacy app

 

[Danny94]

@Pikachu8119

It's true with a fan it would work much better, but thats almost impossible to build in =).

But as you can see in the second picture thermal paste is used to connect the processor and the metal plate behind. The glue on the Graphite Foil works like thermal paste too. So its quite the same just with 2 layers =).
Thermal paste -> metal plate -> thermal paste -> graphite foil.

EDIT: Maybe the metal plate is isolated on the back, i didn´t check it well. That could be a problem and the reason of bad results...

 

[Pikachu8119]

@Pikachu8119

It's true with a fan it would work much better, but thats almost impossible to build in =).

But as you can see in the second picture thermal paste is used to connect the processor and the metal plate behind. The glue on the Graphite Foil works like thermal paste too. So its quite the same just with 2 layers =).
Thermal paste -> metal plate -> thermal paste -> graphite foil.

EDIT: Maybe the metal plate is isolated on the back, i didn´t check it well. That could be a problem and the reason of bad results...

Check temps with phone sensors in programs like Aida, cpuz, etc.

Sent from my Mi-4c using XDA-Developers Legacy app

 

[Danny94]

@Pikachu8119
It's not very meaningful, because it depends on much factors.

But ok there you go:
Rom: RR 5.8.0-20161211 dirty flashed since release.
Power mode/profile: balanced.
Room temperature: 22°c.
Made a restart before testings.
Let cpu-z running behind antutu test for get instant results.

First test:

Second (immediately after):

Third:

 

[itsignas]

So it kinda worked I see, because mine normal Mi4c starts loosing score right after, first benchmark test. Great!

 

[Danny94]

@itsignas
Yeah it's working, but not as much as you think now probably after those images =).

Most of it the Rom ensures cool running.

 

[esmeraldo18]

speading heat over battery isn't a good idea. Heating is not a problem until it is hot enough to melt something. Some part of the phone may get hot but if it is between the ranges no need to take action. replacing thermal paste with a more heat conductive one may help to decrease temperature (plate will become hotter and heat transfer between air and plate will increase) but this seems useless my friend (even dangerous if it makes battery get hotter).

 

[Danny94]

@esmeraldo18
No it doesn't heat up the battery, if you follow well the pictures you can see that i transfer the heat of the plate over the battery outside -> makes it cooler (little bit) around the battery.
Outside it isn´t sticked on the back cover of the phone, it's enough space. So no heat up for battery.