UPS for CoreOne L  

RE:

Anything that has 1000VA or more should be good enough to withstand about 20min outages. 

You can buy some old but still very good APC SmartUPS units ( black ones),just may need to replace batteries.

RE: UPS for CoreOne L

I'm using a CyberPower 1350va.    Got the orange AC alert screen this morning. Had to reset machine. 

RE: UPS for CoreOne L

Have to be careful with the UPS. It needs to be instantaneous or it will trip the power panic logic in the printer. 

RE: UPS for CoreOne L

Some devices have an ability to adjust sensitivity and thus reduce transfer time. By default your UPS has 8ms transfer time, so maybe the Prusa PSU is super sensitive and needs lower switching times, probably something around 2-4ms

RE: UPS for CoreOne L

I just got my Core One L and the first couple 16-18 hour prints went flawlessly, until the third one overnight where I found the printer in the morning beeping nonstop with error code 35337. (AC CONTROLLER FAULT: Power grid is operating outside of specification.)

The help article suggests not to use UPS devices at all. However I was plugged into the same UPS that my MK3S+ has been plugged into without issues for 2-3 years. There were no setup instructions warning to avoid UPS devices.

Disappointingly, this failure mode didn't let me clear the alert and I was forced to reset the unit, causing 90% finished print to be wasted.

Recommend Prusa update the power panic logic to time out the blaring beeping after some time, allow recovering the print, and being less sensitive to common UPS solutions. I don't know what else I could have done.

RE: UPS for CoreOne L

Prusa Preteneded to fix this issue in 6.5.2 I also came from the Mk3S, which was a dependable printer, welcome to endless software issues with the C1L.