BlueWolf
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RPi (Zero) in extreme temperatures experiences

Wed Jul 18, 2018 7:29 pm

Hello there. I am looking for other people who are familiar with putting the Raspberry Pi in extreme temperature conditions. Just curious for experiences/stories/tips/whatnot.

I have a small army of Raspberry Pi Zero's here. And last winter I kinda put them through the test with having some of them outside. They were put in a small box, controlling a relay. Although we did not had a super cold winter, it got down to -35°C for a while. Only one Raspberry failed, except it wasn't the RPi as it turned out. The tiny gpio wire going to the relay couldn't carry the 3.3V over to the relay. The wire was completely solid. Moving it over to the 5V pin fixed it. The RPi itself did great had no issues. I learned that I need to get thicker wires to compensate for the increase in resistance, and keeping them as short as possible.

Interesting the internal cpu temperature (when I was monitoring it) did not get much lower than -15°C. Possible because it was doing work, as well as being right next to the power supply.

I am planning for a 12v battery powered, mobile connected remote camera this winter. Undecided if I have it heated or not. Right now the camera is my biggest question as I don't know how well it performs in cold environments. I'm hoping it will perform all the way down to -40°C which is usually the lowest we get around here.

Right now we have some pretty hot temperatures. One of the Pi's is continuously streaming its webcam feed and is in direct sunlight most of the day. Only now I realised that the internal temperature has risen to 90°C and has been like that for the past few days probably. I find it odd that the cpu has been throttled to 1.0GHz, but 'vcgencmd get_throttled' still shows 0x0. The despite the load being 5.30 it hasn't skipped a beat with streaming. I know coldness shouldn't permanently damage electronics, but does anyone have experience with hot temperatures?

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Imperf3kt
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Re: RPi (Zero) in extreme temperatures experiences

Wed Jul 18, 2018 7:38 pm

The Raspberry Pi zero is set to 1GHz by default, thats why it doesn't say it has been throttled.
Thats odd though, as it should have dropped to ~600 MHz after hitting ~82℃
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mosespi
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Re: RPi (Zero) in extreme temperatures experiences

Wed Jul 18, 2018 7:44 pm

Several summers ago I had a Pi 2 (I think) set up for some power supply/UPS tests inside of a car. It was continuously running for approx 3 or 4 months, right through the hottest parts of summer. We would get heat waves lasting many days of 44C+ temperatures. I can take a guess that the interior temperature of the car was at least 60C during this time, probably higher. CPU temperatures of 95C+ were fairly common on those days, for several hours at a time. There was no fan or forced air cooling, maybe a tiny heatsink on the CPU. Although I was expecting something to fail.. I don't remember a single lockup or failure during that entire time!

I don't know how many summers of that it can take, there is some effect on it's lifetime, but it worked at least one summer!

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BlueWolf
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Re: RPi (Zero) in extreme temperatures experiences

Wed Jul 18, 2018 8:45 pm

Imperf3kt wrote:
Wed Jul 18, 2018 7:38 pm
The Raspberry Pi zero is set to 1GHz by default, thats why it doesn't say it has been throttled.
Thats odd though, as it should have dropped to ~600 MHz after hitting ~82℃
Oh is that so? For some reason I thought 1.2ghz was the default. Yeah then I don't know why it did not do that.

I just realised a program I once installed and stopped using was still running in the background at 100%.. for the past 6 months or so. I always assumed the continuous streaming with RPi Cam Control was just using a lot of power (it does..), but apparently I have been unintentionally trying to melt the Pi by using a cpu sucking program, haha. Well, at least the temperature has now dropped to 79°C after disabling that.

Paul Hutch
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Re: RPi (Zero) in extreme temperatures experiences

Thu Jul 19, 2018 2:48 pm

I left one Pi Zero W with camera outside last winter and it went silent after 4 days continuously below -10°C with overnight lows below -20°C. Rebooted it after it got above freezing and it has worked fine since. Based on my forensics it appeared that the only thing that stopped working was the Wi-Fi. Since the Wi-Fi chip is rated for operation down to -30°C I suspect it was the crystal/caps of the oscillator for the Wi-Fi chip producing an out of tolerance frequency causing connection loss.

Although AFAIK there is no published operating temperature range for the Pi Zero's or 3's I would bet that every component is at least rated for 0°C to 70°C operation (the normal consumer grade range). However as with nearly all operating temperature range specs for electronics the spec is only where the manufacturer guarantees it will work. Very often many or even all of a production run will actually operate well outside the specified range.

One part in a complete Pi system that is often severely limited for guaranteed operating temperature range is the uSd card. Cards are available with wider ranges for industrial use but their price is more than I'm willing to spend.

W. H. Heydt
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Re: RPi (Zero) in extreme temperatures experiences

Thu Jul 19, 2018 4:48 pm

BlueWolf wrote:
Wed Jul 18, 2018 8:45 pm
Imperf3kt wrote:
Wed Jul 18, 2018 7:38 pm
The Raspberry Pi zero is set to 1GHz by default, thats why it doesn't say it has been throttled.
Thats odd though, as it should have dropped to ~600 MHz after hitting ~82℃
Oh is that so? For some reason I thought 1.2ghz was the default. Yeah then I don't know why it did not do that.
That's the Pi3B. The defaults have been: Model B, 700MHz. Model A, 700MHz, Model B+, 700MHz, Model A+, 700MHz, Pi2B (both variants), 900MHz, Pi0/Pi0W, 1GHz, Pi3B, 1.2GHz, Pi3B+, 1.4GHz.

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rpdom
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Re: RPi (Zero) in extreme temperatures experiences

Thu Jul 19, 2018 4:53 pm

W. H. Heydt wrote:
Thu Jul 19, 2018 4:48 pm
That's the Pi3B. The defaults have been: Model B, 700MHz. Model A, 700MHz, Model B+, 700MHz, Model A+, 700MHz, Pi2B (both variants), 900MHz, Pi0/Pi0W, 1GHz, Pi3B, 1.2GHz, Pi3B+, 1.4GHz.
IIRC, when I got my first Pi 1B (May 2012), the default was 600MHz, later raised to 700.

W. H. Heydt
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Re: RPi (Zero) in extreme temperatures experiences

Thu Jul 19, 2018 7:19 pm

rpdom wrote:
Thu Jul 19, 2018 4:53 pm
W. H. Heydt wrote:
Thu Jul 19, 2018 4:48 pm
That's the Pi3B. The defaults have been: Model B, 700MHz. Model A, 700MHz, Model B+, 700MHz, Model A+, 700MHz, Pi2B (both variants), 900MHz, Pi0/Pi0W, 1GHz, Pi3B, 1.2GHz, Pi3B+, 1.4GHz.
IIRC, when I got my first Pi 1B (May 2012), the default was 600MHz, later raised to 700.
Hmmm... Doesn't match my memory and I got one about the same time. I *think* it was spec'd at 700MHz at launch. I've got archives of old versions of Raspbian. I suppose I could write a card of the oldest version I've got and take a look...but I'm not sure it's worth the time and effort.

NewtownGal
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Re: RPi (Zero) in extreme temperatures experiences

Sun Mar 22, 2020 1:35 pm

I want to see just how hot an environment the Pi Zero can operate in. I'm concerned that many thermal details are being glossed over. In particular, I'm trying to pin down the thermal resistance of the Pi Zero and the SDRAM chip that's on top of it. And, I'm trying to confirm where temperature is measured since it appears that people are confusing ambient temperature with the temperature of the cpu die.

When one says the cpu throttles at 82C, isn't that the ARM die temperature, in which case the ambient, i.e., air, temperature is much less ? I've measured a cpu temperature of 46C = 115F in an ambient temperature of only 69F, indicating that the ARM die is a significant 46F = 25C hotter than ambient.

Many people put a small heatsink on the cpu chip, really the stack of the SDRAM chip and the CPU chip, but use the adhesive foam on the heatsink to hold it in place. But the foam has such poor thermal conductivity that it's little better than leaving it off. What is the thermal resistance of the combination of the SDRAM chip and the cpu since the cpu is one of the things we're trying to keep cool ? Wouldn't we cool the chip stack better if we used a top-notch thermal grease on a bare heatsink, and used glue to keep the heatsink from sliding off ? (There are glues and expoxies for heatsinks but their thermal performance is worse than the best greases.)

What temperature range do we need for the SDRAM since SDRAM does not like being hot ?

Would it be better to put a heatsink on the REAR of the Pi, immediately behind the cpu chip, instead of on top ? Or maybe both ?

Thank you in advance for your help.

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Re: RPi (Zero) in extreme temperatures experiences

Sun Mar 22, 2020 2:11 pm

Probably best to start a new thread since this one is two years old, but...

All Pi's are testing during the design phase in an temperature controlled oven, at ambient temperatures of well over 100degC. They still work at that temperature, although they will throttle to the lowest possible speed to keep temperatures down. We have had the SOCs at over 120 and still working. (cannot remember exact numbers). To get to that sort of temperature, you would need very high ambients. They have a shorter lifespan at those sort of values.
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NewtownGal
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Re: RPi (Zero) in extreme temperatures experiences

Sun Mar 22, 2020 3:19 pm

I will start a new thread but let me respond to your comments, which are greatly appreciated.

When people talk about the cpu throttling at 82C, isn't that the die temperature since that's the only temperature the system knows ? What software does the throttling ? So, how is it that people presumably report an ambient temperature of 80C or so when in fact, such a temperature would give a die temperature probably at least 20C higher, namely 100C, in which case the cpu should have started throttling when the ambient was lower, e.g., about 60C ?

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rpdom
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Re: RPi (Zero) in extreme temperatures experiences

Sun Mar 22, 2020 4:16 pm

I sincerely doubt people are seeing ambient temperatures of 80°C :o

Even in the deep deserts.

15-45°C is a more likely range for ambient, unless the Pi is in some sort of oven or up against a heater.
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NewtownGal
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Re: RPi (Zero) in extreme temperatures experiences

Sun Mar 22, 2020 6:30 pm

The problem is that high ambient temperatures can be achieved easily when a device is in a closed container, or when airflow around the device is restricted, so its heat is trapped, and the container is in the sun, especially if the color of the container is chosen poorly. In this case, the ambient temperature is measured inside the container, in the immediate vicinity of the device.

That's why I'm trying to get some thermal conductance values for the Pi Zero cpu chip with the SDRAM on top of it, mounted on the Pi Zero board, to do some thermal calculations. And, since the SDRAM is on top of the cpu chip, I'm wondering if one would be better off removing heat from the backside of the board than on top of the SDRAM chip.

And, I'm trying to get feedback from people who have reported thermal observations to understand precisely where they're measuring temperatures.

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Imperf3kt
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Re: RPi (Zero) in extreme temperatures experiences

Sun Mar 22, 2020 9:49 pm

rpdom wrote:
Sun Mar 22, 2020 4:16 pm
I sincerely doubt people are seeing ambient temperatures of 80°C :o

Even in the deep deserts.

15-45°C is a more likely range for ambient, unless the Pi is in some sort of oven or up against a heater.
You'd be surprised how hot it can get inside something like a regular vehicle such as a car, under the dash in summer. 80°C would not be impossible where I live. (Every summer, the it gets hot enough that the roads melt and turn into a river of molten asphalt)

That said, I've never managed to get a Pi0 to thermally throttle, ever. And I've tried things like covering it with a thick, insulating blanket, in an ambient close to 50°C while pushing the device to its limits.

It just won't throttle, can't get it hot enough.
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drum
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Re: RPi (Zero) in extreme temperatures experiences

Thu Apr 16, 2020 9:01 am

I am in the situation, where I have both zero-w and pi3b+ in a loft space, where the roof gets direct sun and the outside temperature is usually 30+ all summer and can peak at 40+, I have not seen any problems with the pi, themelves, however the USB cameras that are outside and black!! do sometimes lockup when the sun is on them, think this year I'm going to experiment with painting them white.

However at the moment I'm stuck in the UK on lockdown, watching them over the internet, and monitoring the pi load, disk space, and temperature using home assistant, mqtt, and dataplicity Not that I'm bored.....................

NewtownGal
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Re: RPi (Zero) in extreme temperatures experiences

Thu Apr 16, 2020 11:28 am

What happens exactly when the camera locks up ? How do you know the USB camera has locked up ? Does the Pi crash or do you just lose video until the camera cools down ? If the latter, do all USB commands freeze ? Does the Pi CPU spend almost all its time waiting for a particular command to complete, so doing anything else is extremely slow ? Once the camera cools down, does the system recover automatically or do you have to reboot or cycle the power ?

Have you tried using a Pi camera instead of a USB camera ?

householdtechnician
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Re: RPi (Zero) in extreme temperatures experiences

Fri Apr 17, 2020 6:01 am

I once had a Raspberry Pi 0 W project on display all day long in direct sunlight (35 C) inside a closed wooden box. I had a few holes for wires and ventilation but it still managed to get to about 80 C. Didn't throttle though, it still kept going at 1 GHz. But I really wouldn't leave a chip running at 80 C for longer than I need to because it decreases the lifespan.

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