Power supply limits - What can I add?
Hi, I want to add some LED's and big fan's to my printer enclosure as well as a RPi with webcam in the future. How can I know the limit of additional power I can use from the power supply.
Also, if I overload the power supply, is there a risk of damaging any component either from the printer or the power supply? How will I know if it is overloaded.
I have a Mk3S with the black Power Supply, Thank you.
RE: Power supply limits - What can I add?
Hi, I want to add some LED's and big fan's to my printer enclosure as well as a RPi with webcam in the future. How can I know the limit of additional power I can use from the power supply.
Everything I've read indicates that the Mk3 power supply is a bit small if anything. It may be fine most of the time, but if you ever push higher bed and nozzle temps during a busy print, you might run into problems if you draw any more power from it.
Also, if I overload the power supply, is there a risk of damaging any component either from the printer or the power supply? How will I know if it is overloaded.
I'd expect blown fuses at minimum. Sudden failure or smoke might be your indication.
Assuming you're going to use the RPi to run Octoprint to monitor your printer, it's always a good idea to power your monitoring equipment separately from the equipment being monitored. If it goes dark, you won't know whether the printer is on fire or if your cat just bumped the RPi power brick otherwise.
Motors such as fans only add to the concerns. I'm powering my cabinet accessories off a separate 12V 5A supply for now.
RE: Power supply limits - What can I add?
It's never advised to overload the power supply. Without knowing the exact schematic it's hard to tell the outcome. But I assume it doesn't have over-current or under/over voltage protection.
In best case the power supply will just fail. In bad case you might have all kind of different issues before realizing it. In case of failing power supply any damage is possible. That's why it's never advised.
In general I wouldn't add LED, FAN, Raspi and the printer on one power supply. All the components can generate a lot of electrical noise which might affect the operation.
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
RE: Power supply limits - What can I add?
Thank you very much. I think I will all the extras on a separate power supply.
Correct me if i am wrong, but isnt the RPi connected to the printer motherboard? Including power.
RE: Power supply limits - What can I add?
Thank you for the advise.
RE: Power supply limits - What can I add?
The power supply will most likely simply over current and turn itself down. No damage at all, no blown fuses, etc. The 15A fuse on the 24v rail can't even blow because the power supply will limit current to 10 amps or 240W (my MK3 limit); though you could probably blow that fuse if you tried hard enough to crowbar the output wires.
With a 12v 100w wall wart costing under $20, even trying to use 24v seems like extra work for add-ons. And there are some nice 12v open frame supplies, too, for a more professional result (disclaimer, I haven't purchased of used this, just pointing at it for reference).
https://www.amazon.com/GALYGG-Switching-Universal-Regulated-Transformer/dp/B06XRDXDNN
RE: Power supply limits - What can I add?
The power supply will most likely simply over current and turn itself down.
You can check the long thread with power supply failures. None of them shut itself down. It blew up in a different ways. After PR changed their supplier and the PWM, it got quite. So we don't know how the new ones behave.
The most important point, even if it has all the protections on paper, how long does it take until the protection kicks in. Sometimes they are too slow and damage is happening to the attached devices. But again, without knowing used parts and schematic you can only guess how they will behave in extreme situation.
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
RE: Power supply limits - What can I add?
Correct me if i am wrong, but isnt the RPi connected to the printer motherboard? Including power.
Rpi zero, correct. But this is not a device I see as trouble maker. The noisy things can be LED's and FAN's, depending on how they are driven and isolated.
Don't get me wrong, this setup can work. But you don't want to search for the root cause if out of the sudden Rpi or the printer will get unstable from time to time with this setup.
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
RE: Power supply limits - What can I add?
I bought a 350 watt supply to replace the stock one. But then I lose power fail interrupt...
After these posts, I think I will leave the Prusa supply alone and mount the second supply outside the Lack enclosure.
Certainly gives me enough juice for any imaginable accessory, including OctoPrint. I will have an extra 24V rail inside the enclosure.