Raspberry Pi runs hot, performs bad or says "undervoltaged" - how to fix
In this article, we'll cover how you can make your Raspberry Pi (or other microcomputer device) run smoother and how to cool it down if it's running a bit hot.
A Pi that is too hot, is "undervoltaged" or running too many tasks, resulting in it being overloaded, can result in failed prints. This happens because the Raspberry Pi is feeding the 3D printer with the print-information a little bit at a time, and if the Pi is having issues, it might not process info fast enough, resulting in the printer stalling, waiting for commands. This makes the hot nozzle be stuck in the same place for a while, which melts your print and causes some serious deformations or spaghetti.
So, a cool not-stressed Raspberry Pi is good for your prints!
Before looking at what can be done, it's important to note that some Raspberry Pi models are just not fit to run SimplyPrint (or any other way to interact with your printer). The Raspberry Pi Zero W (not version 2) is a good example of a Pi that is just not very powerful, and will always struggle with these kinds of things. Check our article "Pick the right Raspberry Pi for running SimplyPrint / OctoPrint" on which Pi models are fit to run SimplyPrint.
It's also worth to note, that running SimplyPrint through OctoPrint is a bit more heavy than running the "Klipper" firmware with a "Moonraker"-powered service.
The issue might simply be the use of a power supply that is not powerful enough. This is often the case when using a power supply that is not an official Raspberry Pi power supply. If you see a little yellow lightning icon in SimplyPrint, OctoPrint or the warning "Undervoltage detected", switching to another / an official power supply is most likely the fix for you.
If your Raspberry Pi is encased or hidden away in a shelf, behind or under your 3D printer, or in general somewhere hot; let it breathe! The Pi needs to be able to get rid of its heat, so placing it somewhere with airflow, and not putting it in a closed off box or case with no holes goes a long way.
It is, however, important to protect your Raspberry Pi from other electric components and static electricity, so using a case like the SimplyPrint Raspberry Pi case (Thingiverse link), where the Pi is protected, but still has holes for air is recommended.
Sometimes a Pi needs a bit of external help to cool down. Using a small fan that can be mounted directly onto the Pi, and be powered by it, is a good idea to keep your Pi cool and extend its lifespan.
There are multiple different fans to choose from, but just pick whatever fits your setup and your Raspberry Pi model best; find a fan that fits here.
A "heat sink" is a little piece of metal that helps transfer heat away from the Raspberry Pi. A small heat sink is either applied directly on top of the different core components of the Raspberry Pi, or you can go with a large heat sink that covers multiple components or even the whole Pi.
You can also combine fans and heat sink(s) for the optimal Pi-cooler. Find a heat sink for your Pi here.
If you have done all you can to ensure the "outside" health of the Raspberry Pi is good, the next step is to look on the inside; if the "CPU" usage or "memory" is running high, your Pi might be chewing off more it can bite.
Try and limit what the Pi is doing, so if you have a camera attached to your Raspberry Pi, try and unplug it to see if that helps - a webcam cam be a lot for older Pi models to run.
If you're running multiple printers from a single Pi, maybe get a Pi per. printer, or run fewer instances on the Pi with problems.
Furthermore, if you're using the Pi for other purposes as well as 3D printing (running Smart Home / IOT or other services / servers), it just might be too much for your Pi to handle - try and cut off whatever is not necessary.
Sometimes a fresh installation of the Raspberry Pi software/OS can do a lot - and it's a good idea to try and swap out the SD card in the process as well, as a slow, damaged or just old SD card can have a big impact.
That was our list of things you can try to get your Pi in a better state! If you've had no luck with these potential fixes, seeing if a new and fresh Raspberry Pi performs better might be a good idea, to rule out that your Raspberry Pi itself is damaged.
What does a hot or undervoltaged Pi mean for your 3D prints?
A Pi that is too hot, is "undervoltaged" or running too many tasks, resulting in it being overloaded, can result in failed prints. This happens because the Raspberry Pi is feeding the 3D printer with the print-information a little bit at a time, and if the Pi is having issues, it might not process info fast enough, resulting in the printer stalling, waiting for commands. This makes the hot nozzle be stuck in the same place for a while, which melts your print and causes some serious deformations or spaghetti.
So, a cool not-stressed Raspberry Pi is good for your prints!
Old Raspberry Pi model might just be too bad to run your printer
Before looking at what can be done, it's important to note that some Raspberry Pi models are just not fit to run SimplyPrint (or any other way to interact with your printer). The Raspberry Pi Zero W (not version 2) is a good example of a Pi that is just not very powerful, and will always struggle with these kinds of things. Check our article "Pick the right Raspberry Pi for running SimplyPrint / OctoPrint" on which Pi models are fit to run SimplyPrint.
It's also worth to note, that running SimplyPrint through OctoPrint is a bit more heavy than running the "Klipper" firmware with a "Moonraker"-powered service.
What can be done?
1. Undervoltaged? Use the correct power supply
The issue might simply be the use of a power supply that is not powerful enough. This is often the case when using a power supply that is not an official Raspberry Pi power supply. If you see a little yellow lightning icon in SimplyPrint, OctoPrint or the warning "Undervoltage detected", switching to another / an official power supply is most likely the fix for you.
2. Allow your Pi to breathe
If your Raspberry Pi is encased or hidden away in a shelf, behind or under your 3D printer, or in general somewhere hot; let it breathe! The Pi needs to be able to get rid of its heat, so placing it somewhere with airflow, and not putting it in a closed off box or case with no holes goes a long way.
It is, however, important to protect your Raspberry Pi from other electric components and static electricity, so using a case like the SimplyPrint Raspberry Pi case (Thingiverse link), where the Pi is protected, but still has holes for air is recommended.
3. Use a fan
Sometimes a Pi needs a bit of external help to cool down. Using a small fan that can be mounted directly onto the Pi, and be powered by it, is a good idea to keep your Pi cool and extend its lifespan.
There are multiple different fans to choose from, but just pick whatever fits your setup and your Raspberry Pi model best; find a fan that fits here.
4. Use heat sinks
A "heat sink" is a little piece of metal that helps transfer heat away from the Raspberry Pi. A small heat sink is either applied directly on top of the different core components of the Raspberry Pi, or you can go with a large heat sink that covers multiple components or even the whole Pi.
You can also combine fans and heat sink(s) for the optimal Pi-cooler. Find a heat sink for your Pi here.
5. Limit what's running on the Pi
If you have done all you can to ensure the "outside" health of the Raspberry Pi is good, the next step is to look on the inside; if the "CPU" usage or "memory" is running high, your Pi might be chewing off more it can bite.
Try and limit what the Pi is doing, so if you have a camera attached to your Raspberry Pi, try and unplug it to see if that helps - a webcam cam be a lot for older Pi models to run.
If you're running multiple printers from a single Pi, maybe get a Pi per. printer, or run fewer instances on the Pi with problems.
Furthermore, if you're using the Pi for other purposes as well as 3D printing (running Smart Home / IOT or other services / servers), it just might be too much for your Pi to handle - try and cut off whatever is not necessary.
6. Try a fresh install, or a new SD card
Sometimes a fresh installation of the Raspberry Pi software/OS can do a lot - and it's a good idea to try and swap out the SD card in the process as well, as a slow, damaged or just old SD card can have a big impact.
Conclusion
That was our list of things you can try to get your Pi in a better state! If you've had no luck with these potential fixes, seeing if a new and fresh Raspberry Pi performs better might be a good idea, to rule out that your Raspberry Pi itself is damaged.
Updated on: 29/07/2022
Thank you!