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UPS on the printer --- didn't work?!  

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Mirar
(@mirar)
Estimable Member
UPS on the printer --- didn't work?!

So I don't like my prints stopping because the power goes out.

I put an UPS on the printer. A fairly good one (APC Back-UPS pro), should hold for printing for an hour or so at least.

 

But! The printer still reboots when it switches to battery power. Since this is a fairly good UPS, what's up with that? There isn't many milliseconds before it switches over. No normal power supply notices. It could simply be the phase change?

Is this because of the power failure detection on the Prusa? Can I stop this from happening in any way?

Anyone here with experience of UPS and the MK3S?

Posted : 23/11/2021 3:11 pm
Dan Rogers
(@dan-rogers)
Noble Member
Disable power protection if you want - but you will lose the prints that end.

You can disable power protection easily (remove the black/white wire).  But the PSU will still detect the outage and the Einsy will stop your print.  With power protection disabled, you will not have the choice to restart your print.

The only way to truly prevent what you are trying to prevent is to 100% run your rig on a battery power bank / inverter (true sine wave or it won't work).  Those inverters run a few thousand ...  the battery banks run 500 to 1000... and you'll then need a charging system.  Maybe it's time for a Tesla Power wall?

 

Posted : 23/11/2021 3:43 pm
Milos V.
(@milos-v)
Prominent Member
RE: UPS on the printer --- didn't work?!

I am running MK2.5S with simple APC Back-UPS 950VA AVR for about $130 and it holds well. Yes, it will not cover an hour or such, but I have it more for short time power outages. I wait 5-10 minuts and if power is not back, I do stop the print. The reason is to allow the printer to cool down and do not have a clog later.

Posted : 23/11/2021 9:44 pm
Mirar liked
jsw
 jsw
(@jsw)
Noble Member
RE: UPS on the printer --- didn't work?!

Some UPS units lose a few cycles when they go from commercial power to battery power.

This may make the printer think that the power is out.

I have my MK3S on a Cyber Power Best Buy special and when I installed it, I tested it several times during a test print to be sure that if 'shore' power was lost, it would properly take over the load.

Posted : 24/11/2021 2:20 am
Milos V.
(@milos-v)
Prominent Member
RE: UPS on the printer --- didn't work?!

I am in parallel running also desktop PC with monitor, NAS, switch and router. So after powerloss, if printing, I close the work on PC, switch off the PC ASAP and the remaining battery capacity goes for the printer if needed. It holds all these devices without any restart.

Posted : 24/11/2021 10:11 am
Jimbo70
(@jimbo70)
Trusted Member
RE: UPS on the printer --- didn't work?!

Repetier Server will capture the point in the g code when the failure occurs and will allow you to restart the print at that place after power is restored.

Repetier runs on a Raspberry Pi. 

After power is restored start the Servier and your printer, the Server will send give a message - 'do you want to resume print'

...
Posted : 24/11/2021 3:18 pm
Mirar
(@mirar)
Estimable Member
Topic starter answered:
RE: UPS on the printer --- didn't work?!

That should use the exact same tech that I have in my UPS, and you haven't had any issues?

Posted by: @milos-v

I am running MK2.5S with simple APC Back-UPS 950VA AVR for about $130 and it holds well. Yes, it will not cover an hour or such, but I have it more for short time power outages. I wait 5-10 minuts and if power is not back, I do stop the print. The reason is to allow the printer to cool down and do not have a clog later.

Thanks for all the answers about power restore, but 1) I never had a power outtage that the UPS wouldn't be able to deal with without a power out, and 2) I rarely have a print that would handle cooling down of the heatbed without popping off when the power was out...

Posted : 10/12/2021 9:01 am
Milos V.
(@milos-v)
Prominent Member
RE: UPS on the printer --- didn't work?!

No issues, works fine. I just selected UPS with higher power (450 W I think) so the printer is not overloading it in case of power loss. I seems, that the capacitors in the power source or mainboard handle the small drop. So it can be also because of I am running MK2.5S with 12V system, also I am running on 230VAC network. Maybe if all of these can influent.

I need the printer to cool down not to have a clog. In that case I do not care about the print itself, I will not continue.

Posted : 10/12/2021 9:12 am
Mirar liked
MysDawg
(@mysdawg)
Estimable Member
RE: UPS on the printer --- didn't work?!

Recently in Southern California, we have been subject to the power company turning off the power on notice on windy days. I have an APC hooked up and have not had a problem to date. 

Posted : 19/12/2021 5:10 pm
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