3

So I have my Raspberry Pi 3 up and running for about 2 days now. It's running 3 small scripts in the background continuously, which have minimal impact on the CPU. I've never seen the CPU usage go above 2%; it always maintains 0-1%.

On the first day the Pi was running at about 50°C. After sometime, it stabilised to 53°C the entire day. The next morning I checked the temperature and it was around 58°C. I then checked the CPU usage and it still maintained the 0-1% usage.

I then decided to get heatsinks and monitor the temperatures. It was still the same; nothing had changed. I assumed it had something to do with the power supply, but I confirmed that the power supply gave a stable 5.12V for about 10 min. I'm using a fast charger and the supply is rated at 5V 2.0A. So I'm assuming there's no leaking current causing thermal damage to the chip.

My room temperature is around 40°C. I'm sure even at this temperature, the Pi shouldn't have such severe temperature spikes.

This is my RPI3 setup:

  • It's running the latest version of Raspbian.
  • It's connected to LAN and WiFi.
  • I haven't disabled the WiFi yet.
  • One of the GPIOs is used to continuously send HIGH/LOW signal to a relay. 98% of the time the GPIO is sending LOW so there's not much current draw either.
  • None of the USB ports are used
  • the HDMI port is unused.

So what seems to be the problem?

  • 2
    There are likely too many possible factors (Pi faults, power supply faults, software faults, ambient temp, etc.) to make a reasonable attempt at answering your question. Your setup looks fine on paper, aside from the ambient temperature. 40°C is hot. Hot hot. With only an 18°C differential between your CPU and the air I'm not entirely surprised your heatsink didn't do much (although I might check your thermal paste and mounting). Thermal throttling doesn't kick in till 85°C, but if you're worried you might try a fan to wick the heat away a little faster. – goobering Apr 19 '16 at 13:43
  • Ya when you're near the equator the ambient is always HOT. Anyhow the heat sinks are just stuck using double sided tape so thats why I think it made no difference, ill get thermal paste and try again. Adding a fan would result in more current draw, ill keep that as my last option. I'm not worried about thermal throttling. I'm worried about the safety of the chip, if I leave it on for longer than 2 days and if the temps keep rising I have nothing left to do. – Rakshith G B Apr 19 '16 at 14:47
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    Your tape's made of paper and is an insulator - it'll block any heat transfer. Heat sinks won't do much unless there's a good heat conductive connection to the heat source, hence thermal paste. The chip's rated to 125°C, but as long as you're below 85 it should work without any problems. It's possible its life might be a little shorter due to the toasty hotness in your room, but nothing to lose sleep over. – goobering Apr 19 '16 at 14:56
  • Yeah, double sided tape will only make things worse, not help. You mention that you're on the equator? What's the humidity like? If you're talking about 40 C temps, and high humidity, a heatsink isn't going to do much on their own. – Jacobm001 Apr 19 '16 at 15:10
5

Your Pi is NOT getting hot. It is running within its designed operating range.

Don't worry about it unless it exceeds 85℃

2

I feel that the tape only worsens the possibility of heat sink. Also I feel that CPU usage is different from CPU powered up. Since your CPU is powered up always, there will be a heat dissipation for sure. So I feel the behavior is expected!

0

Taking into account that you have room temperature 40°C, 58°C for Raspberry Pi is very cold :)

Modern semiconductor works good with temperature up to 80°C. Do not worry about that.

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