Ender 3 - how to save a print during power outage

I have a small UPS that can support the printer for about 10 minutes

If I have a power out how can I save my work and resume printing later?

It needs to be compiled into the firmware. Usually the printer is storing the current line within the gcode file onto the internal SD card.

The problem is that the heated bed gets cold and if you rely on adhesion based of heat, you are doomed. The print gets loose and will fail, even if you can continue. So you need a print bed that grips onto the print even after a cool down.

When you turn on the printer after a power outage it usually detects the mid print status on SD card and asks to continue the print. It is easy as that, but this is not a guarantee to work. I personal find these option quite useless as the SD card itself is not meant to be writing constantly, which every print with enabled power out recovery does.

I have a UPS here, too for the same reason, but I never repaired the batteries to use it with my printers. I had two outtakes in two years while printing and was lucky only to loos about two hours of print time in total. This happening at the end of an 12 hour print would be bad.

If I would fix and install the UPS here, I probably would tweak the firmware, so that the power out signal would pause the print, the power back signal would continue the print. during pause I would power down the nozzle to save energy.

I would never go for this SD card recovery solution. It only works on paper and when people are testing it without letting the print bed cool down. With non special build plates like glass this will fail as soon as the heat bed reaches around 50°C (PLA) as the print pops off the bed and gets loose. In addition there is a high change the SD cards will get corrupt, as power outtake may happen while writing to it. The cards also get defective far earlier as the FAT16/32 file system is not flash compatible and there would be hundreds of writes every time you print (even without a power outtake).

So from my perspective: You have extra 10 minutes. That is more than I have and unless you have several outtakes a month, I would stick with it or you run into more trouble without having any benefit from it.

Thanks for the information even if it wasnt what I was hoping to hear

I have my printer connected to a 1500W CyberPower sine wave UPS. When the heaters cycle on it says around 20 min. With the heaters off it says around 60 min., so the real time is likely in between.

I suppose the best thing is not to have a print going on when the power fails

but if there is then oh well

Momentary loses of power are infrequent and the UPS can handle those

and fortunately total loss of power is rare in my area

I think, fortunately, most people in the western world, at least, have pretty reliable power. It only that were so for the rest of the world.

At the risk of committing politics I suspect we may be becoming the rest of the world

Fair point. It certainly seems the country is not as bullet proof as it seemed to be in the past. Mind you, there have been traumatic periods since even before the founding. Hoperfully, this one will get resolved & the country will come out even stronger. OK, enough of politics :slight_smile:

I agree

This is the wrong place for politics and I apologize for bringing it up