The Raspberry Pi 4 needs a fan

Post by devinjflick » Wed, Jul 17, 2019, 6:57 PM UTC

geerlingguy wrote: post #15

malensek wrote: post #9

Even the previous-gen Pis would easily throttle under load without a heat sink (although usually installing a decent heat sink was enough to resolve the problem, assuming decent airflow). As the article notes, the heat was mainly from the SoC in the past. The Pi 4 is on a whole different level indeed. I imagine the logic here is the same as with many other Pi accessories: if you need it, you'll buy it or get it as pa…

That’s just it, though. The official Pi power supply is adequate and good for powering the Pi in any condition, but the case is a far cry from adequate. At best, it just toasts everything inside more evenly, at worst it contributes to throttling because now the heat from every other part of the Pi forms a hot thermal blanket over the CPU. I’m amazed they didn’t at least add a few passive ventilation holes or slots, s…

Post by devinjflick » Wed, Jul 17, 2019, 7:01 PM UTC

opmac wrote: post #117

They sell cases with heatsinks and fans for $10-$20. I would just recommend buying one of those versus modding one like the guy in the article did.

Post by Bootwizard » Wed, Jul 17, 2019, 7:13 PM UTC

dboreham wrote: post #160

Bootwizard wrote: post #96

Earlier quoted context omitted.

Damaging temperatures are generally between 90-100°C. Throttling can happen at lower temps and those are usually CPU dependent (and cooler dependent). Also CPUs with less cores handle thermal throttling worse as they have less cores to fallback on if one overheats.

As a sometime hardware engineer, my rule of...er...thumb was that if it was difficult to keep your finger on the device for 5 seconds then it was overheating. Damage to devices certainly doesn't happen at 100C but you might be talking about case temp under some assumptions about how that relates to junction temp for some specific setup. In general its junction temp that decides if the device suffers permanent damage.

Post by prashnts » Wed, Jul 17, 2019, 7:17 PM UTC

prashnts wrote: post #174

I’ve been using old ssd cases (aluminium ones), which would otherwise end up in trash. Drill four holes, use a screw to create threads in those holes. Lay some thermal tape, and mount the pi. I haven’t seen it rise above 60degs — plus it looks alright in my opinion. Few pictures here [1]. I got rid of the ports because I don’t need them (headless) and so they mostly fit entirely. I’ll make some sorta cover though. Ed…

Post by darkmighty » Wed, Jul 17, 2019, 7:23 PM UTC

DINKDINK wrote: post #137

JorgeGT wrote: post #116

Earlier quoted context omitted.

Yep, a lot of people nowadays is using IR cameras without any calibration or understanding of the physics behind the measurement. The truth is, the camera requires an emissivity coefficient to associate the received radiation with the emitter body temperature. There are tables for different types of materials, but the best is to calibrate against a surface thermocouple or similar. A corollary of this is, when you see…

>people nowadays is using IR cameras without any calibration or understanding of the physics behind the measurement The four factors are Emissivity (ε), Absorptivity (α), reflectivity (ρ) and transmissivity (t). Emissivity is only one facet. Ideal is high Emissivity and low reflectivity. https://en.wikipedia.org/wiki/Radiation_properties