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buckeyestargazer
(@buckeyestargazer)
Estimable Member
UPS and Printing

Is anyone successfully using a UPS (uninterruptible power supply) with a MK3S printer?  I occasionally get short power outages of a few seconds that of course mess up the current print.  So I bought a UPS to protect against this but the UPS doesn't stop the print from failing either.  Just wondering if anyone is using a UPS successfully.

Best Answer by Neophyl:

There are several.  Using googles search limited by SITE brought up this for example

https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-general-discussion-announcements-and-releases/prusa-mk3-on-a-ups/

https://forum.prusa3d.com/forum/original-prusa-i3-mmu2s-mmu2-general-discussion-announcements-and-releases/just-fyi-mk3s-with-cyber-power-ups-during-power-failure/

https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-hardware-firmware-and-software-help/when-running-prusa-mk3-on-a-ups/

From a quick skim read then you need one with a very fast switchover time to UPS for it to print without the Mk3 still detecting the power loss and its own recovery mechanism kicking in.  So be cautious of which one you get.

Napsal : 24/12/2022 8:50 pm
RandyM9
(@randym9)
Honorable Member
RE: UPS and Printing

I think there was a recent discussion about this somewhere on the forums. Maybe top level general discussions? I know it’s not the best but did you try a search?

Cheers

Napsal : 26/12/2022 6:36 am
Neophyl
(@neophyl)
Illustrious Member
RE: UPS and Printing

There are several.  Using googles search limited by SITE brought up this for example

https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-general-discussion-announcements-and-releases/prusa-mk3-on-a-ups/

https://forum.prusa3d.com/forum/original-prusa-i3-mmu2s-mmu2-general-discussion-announcements-and-releases/just-fyi-mk3s-with-cyber-power-ups-during-power-failure/

https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-hardware-firmware-and-software-help/when-running-prusa-mk3-on-a-ups/

From a quick skim read then you need one with a very fast switchover time to UPS for it to print without the Mk3 still detecting the power loss and its own recovery mechanism kicking in.  So be cautious of which one you get.

Napsal : 26/12/2022 9:25 am
Agkirk
(@agkirk)
Estimable Member
RE: UPS and Printing

There are different implementations of UPS units.  One type allows up to 30ms to switch from mains power to its internal AC inverter powered by a battery. Another implementation powers the UPS output continuously from the battery backed inverter, using the mains power to continually charge the battery thus eliminating the short power drop when switching.

Napsal : 26/12/2022 8:19 pm
jsw
 jsw
(@jsw)
Famed Member
RE: UPS and Printing

I am using cheap Best Buy special Cyber Power UPS units on both the Prusa and the Ultimaker.  These are the units which need at least a significant fraction of a lost cycle to realize that power is out and switch over.

I've had one hard power failure with the Prusa printing, and it did not miss a beat.  I've also tested a number of times by simply unplugging the UPS from the mains with no issues on either printer.

My conclusion is that both printers can 'take a joke' regarding so many ms of lost power.

Napsal : 27/12/2022 8:48 am
Patrick McNamara
(@patrick-mcnamara)
Estimable Member
RE: UPS and Printing

Unless you are using a double conversion online UPS, you have to disable the power panic feature by unplugging the sensor line.  Otherwise, you will eventually trigger the power panic during the switchover of the UPS.  If you are printing from the SD card, the printer will try and recover and probably do just fine.  If you are printing from Octoprint, it will kill the print.

Napsal : 27/12/2022 3:11 pm
jsw
 jsw
(@jsw)
Famed Member
RE: UPS and Printing

I have never disabled the power panic. I can reliably unplug the UPS from the wall socket and the printer will continue to print.  This was verified during one primary power failure when a print was in progress.  It continued to print until the generator was on line, at which time the UPS switched back to AC.

Napsal : 27/12/2022 3:15 pm
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