voltage from measure_volts

Hi, my raspi4 is booting and running from an USB-SSD Harddrive connected with no additional power for the harddrrive. With "stress" i simulate some stress for CPU / IO and RAM. At the moment (first 6 hours), everything works as expected.

Is this OK for 24/7 running?

Jan

"Officially, the Raspberry Pi Foundation recommends that the temperature of your Raspberry Pi device should be below 85 degrees Celsius for it to work properly. That?s the maximum limit. But it would start throttling at 82 degrees Celsius."

For what its worth., Been on a few months

I've been running that combination on the Pi 3B, 3B+ and 4B for years without issues.

During the stress test it will be thermally throttling, which shouldn't do any harm for short periods, but either a large passive heatsink or a small fan will prevent it getting that hot, and avoid the performance drop off.

---druck

Am 24.09.20 um 06:14 schrieb paul lee:

If you use a heatsink and a small fan you could get

I use now an active cooler... buit this will also use power.

Yes, this was my primary question.

Thanks

Jan

Is there any real point to getting it that low? The cooler is probably using twice as much power as the Pi.

One of mine Pis in shed got down to 19.7C CPU temp during the winter, it didn't run any better than when it was 72.8C in the summer :)

---druck

Serious answer from an ex electronics engineer. Semiconductors and indeed all components age. possibly the worst offenders are capacitors with liquids inside - the old wax paper condensers and modern electrolytics are two culprits that change values with age and may fail completely.

This form of ageing is very much a function of heat. As far as semiconductors go, there are two completely different thermally related failure modes.

One is failure of the hermetic seals to the chips caused by temperature

The second is electromigration. Over time the actual dopant ions physically migrate in the junction area, leading to loss of performance and eventually out of spec. behaviour. Temperature accelerates this.

Operation at junction temperatures near the limit of usually around

I have seen cases of CPU fan failure on SPARC and INTEL CPUs that have destroyed the CPU altogether, although usually the users switch them off when performance becomes erratic.

So in the limit, yes, high temperature and temperature cycling destroys

very hard thing to quantify.

case temperatures, they sizzled with a wet finger. I have had a Schottky diode accidentally shorted across a battery physically unsolder itself...without apparent damage.

So there is a real point, but how important it is? is very hard to quantify.

Its like SSD failure, everyone knows that writes destroy SSDs over time, but how fast?

And then examination of SMART data suggest 'a lot slower than bearings wear out in, or oxide flakes off, a conventional drive'

In reality I suspect your Pi will be obsolete before it dies of heat exhaustion. :-).

Am 29.09.20 um 11:51 schrieb The Natural Philosopher:

thats may be true :-)

Jan

The Pi in question is my very first 256MB model B, obsolete in every way, but just refuses to die - British engineering at its best!

---druck