I'm currently running a Pi2, which has a BME280 (via a hat) and a SSD
attached to it. The Pi is now starting to struggle to generate graphs
for my home website, so I'm thinking of swapping it for a Pi4. A
rummage online doesn't seem to fully answer my questions.

Apart from the Pi4, to upgrade, I know that I will need a bigger power
supply and a HDMI adapter lead, but after, things are a bit vague. Can
I get away with the Pi4 without any additional cooling, or do I need a
heat sink or fan, and if so, how do they get on with the hat ? The
space it is in has had a temperature range of -1 to 40 degrees C, the
mean across that time is about 15.5C.

TIA

Adrian
--
To Reply :
replace "bulleid" with "adrian" - all mail to bulleid is rejected
Sorry for the rigmarole, If I want spam, I'll go to the shops
Every time someone says "I don't believe in trolls", another one dies.

On 09/04/2024 13:52, Adrian wrote:
> I'm currently running a Pi2, which has a BME280 (via a hat) and a SSD
> attached to it.  The Pi is now starting to struggle to generate graphs
> for my home website, so I'm thinking of swapping it for a Pi4.  A
> rummage online doesn't seem to fully answer my questions.
>
> Apart from the Pi4, to upgrade, I know that I will need a bigger power
> supply and a HDMI adapter lead, but after, things are a bit vague.  Can
> I get away with the Pi4 without any additional cooling, or do I need a
> heat sink or fan, and if so, how do they get on with the hat ?  The
> space it is in has had a temperature range of -1 to 40 degrees C, the
> mean across that time is about 15.5C.
>
I am running a Pi4, two SSDS and a TV hat with no cooling. So far its
OK. One of the SSDS gets a bit warm.

The pi itself comes out well below 'temperatures of concern'

> TIA
>
> Adrian

--
In theory, there is no difference between theory and practice.
In practice, there is.
-- Yogi Berra

In article (Dans l'article) <koJxMPHmoTFmFw8W@ku.gro.lloiff>, Adrian
<bulleid@ku.gro.lioff> wrote (écrivait) :

> - a bigger power

And with USB C connector !

I get
<https://www.bol.com/be/fr/p/leicke-raspberry-pi-4-model-b-voeding-ull-s
witching-adaptor-5-1v-3a-met-officiele-koffer-rpi4-case-rw-1876751-ksa-1
5e-051300he-eu-uk-us-adapter-1-5m-kabel-met-schakelaar-tuv/9300000009400
425/>

> - a HDMI adapter

- for mini HDMI -> micro HDMI I get
<https://www.amazon.com.be/dp/B0BRV7BXPB/ref=pe_43847721_689504491_TE_it
em>

-for VGA -> micro HDMI I get
<https://fr.aliexpress.com/item/1005006115048037.html?>

> Can I get away with the Pi4 without any additional cooling

I don't have nor use that.

--
Jean-Pierre Kuypers

Adrian <bulleid@ku.gro.lioff> wrote:
> I'm currently running a Pi2, which has a BME280 (via a hat) and a SSD
> attached to it. The Pi is now starting to struggle to generate graphs
> for my home website, so I'm thinking of swapping it for a Pi4. A
> rummage online doesn't seem to fully answer my questions.
>
If you're buying the Pi4 then why not go for a Pi5, there's very
little difference in the price.

> Apart from the Pi4, to upgrade, I know that I will need a bigger power
> supply and a HDMI adapter lead, but after, things are a bit vague. Can
> I get away with the Pi4 without any additional cooling, or do I need a
> heat sink or fan, and if so, how do they get on with the hat ? The
> space it is in has had a temperature range of -1 to 40 degrees C, the
> mean across that time is about 15.5C.
>
I've run two Pi4 systems without heatsink or fan for a very long time
with no issues at all. I've just looked at one of them, it's been
running at least since May 2023. As I understand it anyway the
system will simply slow down if it thinks it's getting too hot.

--
Chris Green
·

On 09/04/2024 13:52, Adrian wrote:
> I'm currently running a Pi2, which has a BME280 (via a hat) and a SSD
> attached to it. The Pi is now starting to struggle to generate graphs
> for my home website, so I'm thinking of swapping it for a Pi4. A
> rummage online doesn't seem to fully answer my questions.
>
> Apart from the Pi4, to upgrade, I know that I will need a bigger power
> supply and a HDMI adapter lead, but after, things are a bit vague. Can
> I get away with the Pi4 without any additional cooling, or do I need a
> heat sink or fan, and if so, how do they get on with the hat ? The
> space it is in has had a temperature range of -1 to 40 degrees C, the
> mean across that time is about 15.5C.
>
> TIA
>
> Adrian

Adrian,

No problem with the other suggestions.

When you say "starting to struggle" what have you measured? Are you running
out of memory, CPU power, disk I/O, or network I/O? I think it would be useful
to know what exactly in your system needs changing.

It's possible that a Pi 3B+ might be a sufficient upgrade (but can you still
get them?).

The Pi-5 creates quite a bit more heat than the Pi 4, and has some software
compatibility issues, so unless you really need the 5, stick to the 4. (I have
both here). If you are not running headless, the Pi 400 has a heatsink and
keyboard built in. I have a couple here and have been very pleased with them.
One even runs both Windows and Linux, that's using the Twister OS. It uses
about 2 GB of its 4 GB memory, and averages 10-12% CPU.
--
Cheers,
David
Web: https://www.satsignal.eu

On 09/04/2024 14:11, Chris Green wrote:
> Adrian <bulleid@ku.gro.lioff> wrote:
>> I'm currently running a Pi2, which has a BME280 (via a hat) and a SSD
>> attached to it. The Pi is now starting to struggle to generate graphs
>> for my home website, so I'm thinking of swapping it for a Pi4. A
>> rummage online doesn't seem to fully answer my questions.
>>
> If you're buying the Pi4 then why not go for a Pi5, there's very
> little difference in the price.
>
>

nearly twice the price for entry level.

.......
....

> I've run two Pi4 systems without heatsink or fan for a very long time
> with no issues at all. I've just looked at one of them, it's been
> running at least since May 2023. As I understand it anyway the
> system will simply slow down if it thinks it's getting too hot.
>
AIUI that is the case

When you are using it in 'burst mode' to do something compute intense it
will get hot.

But not that hot... :-)

--
If you tell a lie big enough and keep repeating it, people will
eventually come to believe it. The lie can be maintained only for such
time as the State can shield the people from the political, economic
and/or military consequences of the lie. It thus becomes vitally
important for the State to use all of its powers to repress dissent, for
the truth is the mortal enemy of the lie, and thus by extension, the
truth is the greatest enemy of the State.

Joseph Goebbels

On 09/04/2024 15:38, David Taylor wrote:
> On 09/04/2024 13:52, Adrian wrote:
>> I'm currently running a Pi2, which has a BME280 (via a hat) and a SSD
>> attached to it.  The Pi is now starting to struggle to generate graphs
>> for my home website, so I'm thinking of swapping it for a Pi4.  A
>> rummage online doesn't seem to fully answer my questions.
>>
>> Apart from the Pi4, to upgrade, I know that I will need a bigger power
>> supply and a HDMI adapter lead, but after, things are a bit vague.  Can
>> I get away with the Pi4 without any additional cooling, or do I need a
>> heat sink or fan, and if so, how do they get on with the hat ?  The
>> space it is in has had a temperature range of -1 to 40 degrees C, the
>> mean across that time is about 15.5C.
>>
>> TIA
>>
>> Adrian
>
> Adrian,
>
> No problem with the other suggestions.
>
> When you say "starting to struggle" what have you measured?  Are you
> running out of memory, CPU power, disk I/O, or network I/O?  I think it
> would be useful to know what exactly in your system needs changing.
>
> It's possible that a Pi 3B+ might be a sufficient upgrade (but can you
> still get them?).
>
Can in uk at the moment. all sorts.

> The Pi-5 creates quite a bit more heat than the Pi 4, and has some
> software compatibility issues, so unless you really need the 5, stick to
> the 4.  (I have both here).

I think that's a good point

If you are not running headless, the Pi 400
> has a heatsink and keyboard built in.  I have a couple here and have
> been very pleased with them. One even runs both Windows and Linux,
> that's using the Twister OS.  It uses about 2 GB of its 4 GB memory, and
> averages 10-12% CPU.

--
If you tell a lie big enough and keep repeating it, people will
eventually come to believe it. The lie can be maintained only for such
time as the State can shield the people from the political, economic
and/or military consequences of the lie. It thus becomes vitally
important for the State to use all of its powers to repress dissent, for
the truth is the mortal enemy of the lie, and thus by extension, the
truth is the greatest enemy of the State.

Joseph Goebbels

In message <uv3jsh$l8h$1@dont-email.me>, David Taylor
<david-taylor@blueyonder.co.uk.invalid> writes
>On 09/04/2024 13:52, Adrian wrote:
>> I'm currently running a Pi2, which has a BME280 (via a hat) and a SSD
>> attached to it. The Pi is now starting to struggle to generate graphs
>> for my home website, so I'm thinking of swapping it for a Pi4. A
>> rummage online doesn't seem to fully answer my questions.
>> Apart from the Pi4, to upgrade, I know that I will need a bigger
>>power
>> supply and a HDMI adapter lead, but after, things are a bit vague. Can
>> I get away with the Pi4 without any additional cooling, or do I need a
>> heat sink or fan, and if so, how do they get on with the hat ? The
>> space it is in has had a temperature range of -1 to 40 degrees C, the
>> mean across that time is about 15.5C.
>> TIA
>> Adrian
>
>Adrian,
>
>No problem with the other suggestions.
>
>When you say "starting to struggle" what have you measured? Are you
>running out of memory, CPU power, disk I/O, or network I/O? I think it
>would be useful to know what exactly in your system needs changing.
>

The Pi is run headless in the normal way of things, but being able to
connect a keyboard, mouse and monitor is helpful for the initial set up.

I monitor (every minute), CPU usage and temperature, as well as free
memory (in addition to time to ping the router, space used on the SD
card and SSD, bytes in/out and logical block access on the SSD). I can
also see (using ls) how long it takes for the graphs (as png files) to
be created.

On Sunday, I updated matplotlib (hoping, and failing, to fix a rendering
problem). The previous version was ~2.5 years old. Since then, the
time taken to generate graphs has risen enormously. What had taken ~5
minutes is now taking 12, which isn't good when you do it at a 10 minute
interval. Saturday's CPU usage was a fairly typical 0.01 3.27 0,65
(min, max, mean), whereas yesterday's was 0.15 9.24 3.92. Memory usage
doesn't seem vastly different, and CPU temperature was slightly lower,
although that is to an extent governed by the ambient temperature, which
has dropped slightly. The other resources appeared to be normalish
(they vary a bit anyway). So from what I can see, the problem is that
I'm badly lacking in CPU power rather than other resources.

>It's possible that a Pi 3B+ might be a sufficient upgrade (but can you
>still get them?).
>

The rationale of looking at a Pi4 rather than a Pi3, was to make a jump
ahead so that I've got some spare capacity on the Pi, which gives me
room for further expansion, which I'm likely to need in the near future.
For no obvious reason, the Pi5 hadn't entered my thought processes.

Thanks

Adrian
--
To Reply :
replace "bulleid" with "adrian" - all mail to bulleid is rejected
Sorry for the rigmarole, If I want spam, I'll go to the shops
Every time someone says "I don't believe in trolls", another one dies.

The Natural Philosopher <tnp@invalid.invalid> wrote:
> On 09/04/2024 14:11, Chris Green wrote:
> > Adrian <bulleid@ku.gro.lioff> wrote:
> >> I'm currently running a Pi2, which has a BME280 (via a hat) and a SSD
> >> attached to it. The Pi is now starting to struggle to generate graphs
> >> for my home website, so I'm thinking of swapping it for a Pi4. A
> >> rummage online doesn't seem to fully answer my questions.
> >>
> > If you're buying the Pi4 then why not go for a Pi5, there's very
> > little difference in the price.
> >
> >
>
> nearly twice the price for entry level.
>
Pi Hut:-

4Gb Pi 5 - £58.50
4Gb Pi 4 - £55.00
1Gb Pi 4 - £35.00

You can't get a 1Gb Pi 5, until recently you couldn't get a 1Gb Pi 4.
If I was buying a Pi 4 now I wouldn't go for a 1Gb one.

--
Chris Green
·

David Taylor <david-taylor@blueyonder.co.uk.invalid> wrote:
> On 09/04/2024 13:52, Adrian wrote:
> > I'm currently running a Pi2, which has a BME280 (via a hat) and a SSD
> > attached to it. The Pi is now starting to struggle to generate graphs
> > for my home website, so I'm thinking of swapping it for a Pi4. A
> > rummage online doesn't seem to fully answer my questions.
> >
> > Apart from the Pi4, to upgrade, I know that I will need a bigger power
> > supply and a HDMI adapter lead, but after, things are a bit vague. Can
> > I get away with the Pi4 without any additional cooling, or do I need a
> > heat sink or fan, and if so, how do they get on with the hat ? The
> > space it is in has had a temperature range of -1 to 40 degrees C, the
> > mean across that time is about 15.5C.
> >
> > TIA
> >
> > Adrian
>
> Adrian,
>
> No problem with the other suggestions.
>
> When you say "starting to struggle" what have you measured? Are you running
> out of memory, CPU power, disk I/O, or network I/O? I think it would be useful
> to know what exactly in your system needs changing.
>
> It's possible that a Pi 3B+ might be a sufficient upgrade (but can you still
> get them?).
>
Yes, but a 1Gb Pi 3b costs more than a 1Gb Pi 4 so there's not much
point in buying one unless the lower power consumption is really
important.

> The Pi-5 creates quite a bit more heat than the Pi 4, and has some software
> compatibility issues, so unless you really need the 5, stick to the 4. (I have
> both here). If you are not running headless, the Pi 400 has a heatsink and
> keyboard built in. I have a couple here and have been very pleased with them.
> One even runs both Windows and Linux, that's using the Twister OS. It uses
> about 2 GB of its 4 GB memory, and averages 10-12% CPU.

When idle there's little difference, e.g. :-

"We also ran a test to measure the heat generated by the devices
during use. The comparison shows that both Raspberry Pi 5 and
Raspberry Pi 4 generate similar amounts of heat. In terms of power
consumption, the PI4 and PI5 have similar power consumption when not
running programs. However, during video playback, there is only a
small difference of 0.2 watts in their power consumption."

The Pi 5 *can* use more power but when doing the 'same thing' the
power consumption is pretty close to that of the Pi 4.

--
Chris Green
·

On 09.04.2024 15:11, Chris Green wrote:
> If you're buying the Pi4 then why not go for a Pi5, there's very
> little difference in the price.
>
I support that. I have been using a Pi4 8 GB with SSB, and replaced it
with a Pi5 8 GB. Don't know what you will be using it for, but for web
surfing there is quite a difference. The Pi4 was just too slow at
reloading webpages, so I had to steel the PC from my wife. With the Pi5
there is not much difference from a newly built PC, concerning web surfing.
Both Pi4 and Pi5 are in Flirc no-fan cases, and the temperature is not
high. 60 degrees are seldom seen.
--
Jesper

On 09.04.2024 18:24, Jesper wrote:
> On 09.04.2024 15:11, Chris Green wrote:
>> If you're buying the Pi4 then why not go for a Pi5, there's very
>> little difference in the price.
>>
> I support that. I have been using a Pi4 8 GB with SSB, and replaced it
> with a Pi5 8 GB. Don't know what you will be using it for, but for web
> surfing there is quite a difference. The Pi4 was just too slow at
> reloading webpages, so I had to steel the PC from my wife. With the Pi5
> there is not much difference from a newly built PC, concerning web surfing.
> Both Pi4 and Pi5 are in Flirc no-fan cases, and the temperature is not
> high. 60 degrees are seldom seen.

I forgot to mention that the Pi5 needs a 5 amp powersupply to be at its
best.
--
Jesper

On 09/04/2024 16:52, Chris Green wrote:
> The Natural Philosopher <tnp@invalid.invalid> wrote:
>> On 09/04/2024 14:11, Chris Green wrote:
>>> Adrian <bulleid@ku.gro.lioff> wrote:
>>>> I'm currently running a Pi2, which has a BME280 (via a hat) and a SSD
>>>> attached to it. The Pi is now starting to struggle to generate graphs
>>>> for my home website, so I'm thinking of swapping it for a Pi4. A
>>>> rummage online doesn't seem to fully answer my questions.
>>>>
>>> If you're buying the Pi4 then why not go for a Pi5, there's very
>>> little difference in the price.
>>>
>>>
>>
>> nearly twice the price for entry level.
>>
> Pi Hut:-
>
> 4Gb Pi 5 - £58.50
> 4Gb Pi 4 - £55.00
> 1Gb Pi 4 - £35.00
>
> You can't get a 1Gb Pi 5, until recently you couldn't get a 1Gb Pi 4.
> If I was buying a Pi 4 now I wouldn't go for a 1Gb one.
>
I did. Running _headless_ it is more than enough.

$ free -m
total used free shared buff/cache
available
Mem: 907 257 297 3 418
650
Swap: 99 0 99

I sometimes run short of CPU, but never RAM

>

--
To ban Christmas, simply give turkeys the vote.

On 09/04/2024 13:52, Adrian wrote:
> Apart from the Pi4, to upgrade, I know that I will need a bigger power
> supply and a HDMI adapter lead, but after, things are a bit vague.  Can
> I get away with the Pi4 without any additional cooling, or do I need a
> heat sink or fan, and if so, how do they get on with the hat ?  The
> space it is in has had a temperature range of -1 to 40 degrees C, the
> mean across that time is about 15.5C.
40C is quite a high ambient temperature. If you are going to run the Pi
4B hard with the likes of matplotlib, passive cooling my not be enough
to stop it throttling. One of mine has a large heat sink case with no
fan and never goes over 60C, but that's at a 20C ambient. For 40C
ambient, I would recommend a fan case, go for a 40mm fan if you want it
to be quiet, 30mm ones can be noisy.
---druck

On 09/04/2024 16:30, Adrian wrote:
> In message <uv3jsh$l8h$1@dont-email.me>, David Taylor
> <david-taylor@blueyonder.co.uk.invalid> writes
>> When you say "starting to struggle" what have you measured?  Are you
>> running out of memory, CPU power, disk I/O, or network I/O?  I think
>> it would be useful to know what exactly in your system needs changing.
>>
>
> The Pi is run headless in the normal way of things, but being able to
> connect a keyboard, mouse and monitor is helpful for the initial set up.
>
> I monitor (every minute), CPU usage and temperature, as well as free
> memory (in addition to time to ping the router, space used on the SD
> card and SSD, bytes in/out and logical block access on the SSD).  I can
> also see (using ls) how long it takes for the graphs (as png files) to
> be created.
I do the similar data gathering on my 16 Raspberry Pi's (a mix of 0W,
02W, 2B, 3A, 3B, 3B+, 4B and 5B), each runs Python services which make
frequent readings of CPU and environment temperatures, network latencies
and various physical sensors and creates a rolling 15 minute average
with min and max values. They also run Python flask web servers allowing
all the data to be read every 15 minutes by a master Pi 4 using curl
commands (much faster than ssh'ing to each box).
Only the single core Pi Zeros show any significant latency when reading
a few dozen DS18B20 single wire temperature sensors, the Pi Zero 2W and
Pi 2B run at the same clock rate, but benefit from the extra cores.
> On Sunday, I updated matplotlib (hoping, and failing, to fix a rendering
> problem).  The previous version was ~2.5 years old.  Since then, the
> time taken to generate graphs has risen enormously.  What had taken ~5
> minutes is now taking 12, which isn't good when you do it at a 10 minute
> interval.
That's quite a lot of time for rendering. What I do is on the Pi is run
a Python uwsgi program which process all the data which has been stored
in sqlite3 databases, producing a bit of HTML and Javacript which
utilises google charts to the the plotting. The processing takes the Pi
4B under a second, and can plot the data itself in Chromium in a few
seconds, but I mainly access it from faster Linux boxes, where rendering
of the google charts in almost instant.
Perhaps you could also perform the rendering on a meatier machine too.
---druck

In message <uv4991$efer$2@dont-email.me>, druck <news@druck.org.uk>
writes
>That's quite a lot of time for rendering. What I do is on the Pi is run
>a Python uwsgi program which process all the data which has been stored
>in sqlite3 databases, producing a bit of HTML and Javacript which
>utilises google charts to the the plotting. The processing takes the Pi
>4B under a second, and can plot the data itself in Chromium in a few
>seconds, but I mainly access it from faster Linux boxes, where
>rendering of the google charts in almost instant.
>
>Perhaps you could also perform the rendering on a meatier machine too.
>

I did think about that, but that would mean leaving one of my PCs on
24x7 which I'm not keen on.

Adrian
--
To Reply :
replace "bulleid" with "adrian" - all mail to bulleid is rejected
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In message <uv494r$efer$1@dont-email.me>, druck <news@druck.org.uk>
writes
>On 09/04/2024 13:52, Adrian wrote:
>> Apart from the Pi4, to upgrade, I know that I will need a bigger
>>power supply and a HDMI adapter lead, but after, things are a bit
>>vague.  Can I get away with the Pi4 without any additional cooling, or
>>do I need a heat sink or fan, and if so, how do they get on with the
>>hat ?  The space it is in has had a temperature range of -1 to 40
>>degrees C, the mean across that time is about 15.5C.
>
>40C is quite a high ambient temperature. If you are going to run the Pi
>4B hard with the likes of matplotlib, passive cooling my not be enough
>to stop it throttling. One of mine has a large heat sink case with no
>fan and never goes over 60C, but that's at a 20C ambient. For 40C
>ambient, I would recommend a fan case, go for a 40mm fan if you want it
>to be quiet, 30mm ones can be noisy.
>

40 was probably a one off (heat wave), but mid 30s occur every summer
month.

I've been looking at fan cases, but they all seem to prevent the use of
the HAT, which means I won't be able to find out what the ambient
temperature is. I suppose I could design one of my own.

Adrian
--
To Reply :
replace "bulleid" with "adrian" - all mail to bulleid is rejected
Sorry for the rigmarole, If I want spam, I'll go to the shops
Every time someone says "I don't believe in trolls", another one dies.

On 09/04/2024 21:40, druck wrote:
> On 09/04/2024 13:52, Adrian wrote:
>> Apart from the Pi4, to upgrade, I know that I will need a bigger power
>> supply and a HDMI adapter lead, but after, things are a bit vague.
>> Can I get away with the Pi4 without any additional cooling, or do I
>> need a heat sink or fan, and if so, how do they get on with the hat ?
>> The space it is in has had a temperature range of -1 to 40 degrees C,
>> the mean across that time is about 15.5C.
>
> 40C is quite a high ambient temperature. If you are going to run the Pi
> 4B hard with the likes of matplotlib, passive cooling my not be enough
> to stop it throttling. One of mine has a large heat sink case with no
> fan and never goes over 60C, but that's at a 20C ambient. For 40C
> ambient, I would recommend a fan case, go for a 40mm fan if you want it
> to be quiet, 30mm ones can be noisy.
>
> ---druck
>

On Pi4 I use the Argon ONE V2 case - good case with sensible fan. I have
a V3 for the Pi5, excellent with their M2 bottom. Both available from
the Pi Hut UK

--
Chris

Adrian <bulleid@ku.gro.lioff> wrote:
> In message <uv4991$efer$2@dont-email.me>, druck <news@druck.org.uk>
> writes
> >That's quite a lot of time for rendering. What I do is on the Pi is run
> >a Python uwsgi program which process all the data which has been stored
> >in sqlite3 databases, producing a bit of HTML and Javacript which
> >utilises google charts to the the plotting. The processing takes the Pi
> >4B under a second, and can plot the data itself in Chromium in a few
> >seconds, but I mainly access it from faster Linux boxes, where
> >rendering of the google charts in almost instant.
> >
> >Perhaps you could also perform the rendering on a meatier machine too.
> >
>
> I did think about that, but that would mean leaving one of my PCs on
> 24x7 which I'm not keen on.
>
Get a PC that's as low powered as a Pi, there are such beasts around
nowadays and you can even find quite cheap refurbished ones. I like
Fujitsu Esprimos, my desktop machine is an Esprimo P910 which is
getting rather long in the tooth now (and consumes 18 watts at idle).
I'm getting an Esprimo Q957 to replace it, that idles at about 5
watts. There are lots of different models with different capabilities
and you can find even lower power ones than the Q957.

--
Chris Green
·

On 09/04/2024 21:40, druck wrote:
> On 09/04/2024 13:52, Adrian wrote:
>> Apart from the Pi4, to upgrade, I know that I will need a bigger power
>> supply and a HDMI adapter lead, but after, things are a bit vague.
>> Can I get away with the Pi4 without any additional cooling, or do I
>> need a heat sink or fan, and if so, how do they get on with the hat ?
>> The space it is in has had a temperature range of -1 to 40 degrees C,
>> the mean across that time is about 15.5C.
>
> 40C is quite a high ambient temperature.

Not where I have worked...

Many years ago a small piece of equipment I had designed, housed in a
totally enclosed steel rack mount case failed after it had been on for
over a day.

It came back to me. It was working perfectly.

So I left it on for a day in the lab with a thermometer probe inside,
It got to well over 90°C inside.

Beyond the upper limits of the commercial chips it was built from. They
were well over 100°C case when opened it up.

We changed the case design and punched some air holes in it, and the
problem never reoccurred.

There are three relevant points here.

The first is that silicon chips themselves survive extremely high
internal temperatures. I have had a power Schottky diode unsolder itself
when connected across a battery. The chips will generally suffer
permanent damage at somewhere around 180°C . Which is a good thing since
they are soldered to a board using hot air at a lot more than that.

The second thing us that they will start to exhibit seriously out of
spec. behaviour at their rated *ambient* temperatures - usually +75°C
for ICs. Inside the chip may well be a lot warmer than that.

The final thing is to understand the difference between a closed box,
thermal convection cooling and forced air cooling. the is roughly a
25:5:1 ratio in cooling between the three cases.

How many Pis are in *closed* boxes *without* fans?

It's less an issue of 'do I need a fan?' or 'its 40°C ambient' than 'is
any hot air going to escape?'

With case temperatures up to well over 100°C possible for power devices,
the difference to an ambient of 40°C is not the much worse than say,
25°C. at a device case temperature of 100°C it is the difference between
a 75°C delta and 60°C delta - not that great really

And a Pi draws somewhere in the 3-5W region. And has lots of board
surface area to dissipate that.

From the Pi forum

"I have put the Pi4 in an airtight enclosure (with a big passive
heatsink), locked the frequency to 1500Mhz, overvoltage=4 and have
cpuburn running for about two hours. Ambient temp inside the box is 54
degrees celsius now.

vcgencmd measure_temp and vcgencmd measure_temp pmic show:

Pi4 CPU temp=124.0'C
Pi4 PMIC temp=129.7'C

And it's still running fine, have a chromium open and can surf the web.
I'm quite amazed."

https://forums.raspberrypi.com/viewtopic.php?t=264786

The whole thread is well worth reading.

And complements what I am saying, that only in a sealed enclosure where
no convection is possible can you get to super high temeperatures, and
in normal use the CPU will in any case throttle back

If you are going to run the Pi
> 4B hard with the likes of matplotlib, passive cooling my not be enough
> to stop it throttling.

That is a very hand wavey statement.

Passive cooling in a car in the sun with the windows closed yes, passive
cooling in a well ventilated case in a room at 40°C, no way.

> One of mine has a large heat sink case with no
> fan and never goes over 60C, but that's at a 20C ambient. For 40C
> ambient, I would recommend a fan case, go for a 40mm fan if you want it
> to be quiet, 30mm ones can be noisy.
>
Personally year of designing high power audio amplifiers and dealing
with computer hardware says 'bullshit'. You simply don't need fans for a
board doing 5W. You can get that out of a single small transistor with
a heatsink clipped on it. You can get that out of a TO3 packaged power
transistor with no heat sink *at all*.

And a PI4B board is a *lot* more surface area than that.

Currently this rooms is at 24.2°C according to a thermometer equipped
pico PI and the resident 4B that is in free air is showing this:

me@Coriolanus:~$ vcgencmd measure_temp
temp=53.5'C
me@Coriolanus:~$ vcgencmd measure_temp pmic
temp=45.8'C

So at idle -ish the chip internals are 29.3°C - call it 30°C over ambient.

at 40°C ambient the chip internals will be up around 70°C.

That is nothing.

"we throttle the CPU when it get to 85 to keep the temperatures down.
I've never seen anything over 90 in normal usage"

Is what the Raspberry Pi engineer says the chips do, in that thread I
referred to above.

In short *unless* you put the pi in an airtight case and wrap it in
insulation or leave it in the midday sun, it doesn't need a fan.

But people are just used to old school SPARC and INTEL chip that kicked
out upwards of 50W at idle, needing a fan. In hard use some SPARCs
would draw up to 300W!!!

Of all the customer returns on SPARC workstations I can remember they
were all dead fans or dead cpus (with dead fans as well).

--
“There are two ways to be fooled. One is to believe what isn’t true; the
other is to refuse to believe what is true.”

—Soren Kierkegaard

On 09/04/2024 22:19, Adrian wrote:
> 40 was probably a one off (heat wave), but mid 30s occur every summer
> month.
>
> I've been looking at fan cases, but they all seem to prevent the use of
> the HAT, which means I won't be able to find out what the ambient
> temperature is.  I suppose I could design one of my own

Seriously, you don't need a fan.

Just a *ventilated* case.

I am designing a case for mine right now, featuring a complete grille in
one end wall.

Experience shows that as long as hot air can escape and draw in cooler
air, all will be well

--
"I am inclined to tell the truth and dislike people who lie consistently.
This makes me unfit for the company of people of a Left persuasion, and
all women"

In message <cuuhek-vqs4.ln1@esprimo.zbmc.eu>, Chris Green <cl@isbd.net>
writes
>Get a PC that's as low powered as a Pi, there are such beasts around
>nowadays and you can even find quite cheap refurbished ones. I like
>Fujitsu Esprimos, my desktop machine is an Esprimo P910 which is
>getting rather long in the tooth now (and consumes 18 watts at idle).
>I'm getting an Esprimo Q957 to replace it, that idles at about 5
>watts. There are lots of different models with different capabilities
>and you can find even lower power ones than the Q957.
>

Thanks. An interesting looking little beastie, but the only place I
could find selling them was Currys, and they appear to be for trade
sales only.

Adrian
--
To Reply :
replace "bulleid" with "adrian" - all mail to bulleid is rejected
Sorry for the rigmarole, If I want spam, I'll go to the shops
Every time someone says "I don't believe in trolls", another one dies.

In message <uv5lop$s7bl$2@dont-email.me>, The Natural Philosopher
<tnp@invalid.invalid> writes
>On 09/04/2024 22:19, Adrian wrote:
>> 40 was probably a one off (heat wave), but mid 30s occur every summer
>>month.
>> I've been looking at fan cases, but they all seem to prevent the use
>>of the HAT, which means I won't be able to find out what the ambient
>>temperature is.  I suppose I could design one of my own
>
>Seriously, you don't need a fan.
>
>Just a *ventilated* case.
>
>I am designing a case for mine right now, featuring a complete grille
>in one end wall.
>
>Experience shows that as long as hot air can escape and draw in cooler
>air, all will be well
>

Thanks.

There appear to be several likely looking cases on Thingiverse (other
sites available), so I suspect that I'll download one of those, and if
needs be tweak it for my needs.

Adrian
--
To Reply :
replace "bulleid" with "adrian" - all mail to bulleid is rejected
Sorry for the rigmarole, If I want spam, I'll go to the shops
Every time someone says "I don't believe in trolls", another one dies.

Adrian <bulleid@ku.gro.lioff> wrote:
> In message <cuuhek-vqs4.ln1@esprimo.zbmc.eu>, Chris Green <cl@isbd.net>
> writes
> >Get a PC that's as low powered as a Pi, there are such beasts around
> >nowadays and you can even find quite cheap refurbished ones. I like
> >Fujitsu Esprimos, my desktop machine is an Esprimo P910 which is
> >getting rather long in the tooth now (and consumes 18 watts at idle).
> >I'm getting an Esprimo Q957 to replace it, that idles at about 5
> >watts. There are lots of different models with different capabilities
> >and you can find even lower power ones than the Q957.
> >
>
> Thanks. An interesting looking little beastie, but the only place I
> could find selling them was Currys, and they appear to be for trade
> sales only.
>
Look on eBay, there's a German company selling refurbished Q957s. The
current model is the Q958 (I think), you'll probably find more people
selling that.

--
Chris Green
·

On 10/04/2024 14:12, Adrian wrote:
> In message <uv5lop$s7bl$2@dont-email.me>, The Natural Philosopher
> <tnp@invalid.invalid> writes
>> On 09/04/2024 22:19, Adrian wrote:
>>> 40 was probably a one off (heat wave), but mid 30s occur every summer
>>> month.
>>>  I've been looking at fan cases, but they all seem to prevent the use
>>> of the HAT, which means I won't be able to find out what the ambient
>>> temperature is.  I suppose I could design one of my own
>>
>> Seriously, you don't need a fan.
>>
>> Just a *ventilated* case.
>>
>> I am designing a case for mine right now, featuring a complete grille
>> in one end wall.
>>
>> Experience shows that as long as hot air can escape and draw in cooler
>> air, all will be well
>>
>
>
> Thanks.
>
> There appear to be several likely looking cases on Thingiverse (other
> sites available), so I suspect that I'll download one of those, and if
> needs be tweak it for my needs.
>
I'll try and post mine somewhere. Finished it last night,. It's working
well with two SSDS and a chip temp of around 65°C-75°C dependent on load.

$ vcgencmd measure_temp
temp=68.1'C

Can you tweak STLs?

> Adrian

--
“Politics is the art of looking for trouble, finding it everywhere,
diagnosing it incorrectly and applying the wrong remedies.”
― Groucho Marx