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.

RE: UPS for CoreOne L

https://github.com/prusa3d/Prusa-Firmware-Buddy/releases/tag/v6.5.3 6.5.3 bumped allowed voltage, try this, maybe it will help

RE: UPS for CoreOne L

It only changed the max wall voltage to 264V.  That shouldn't have fixed the problem. Unless they made other changes that were not disclosed,  I have not tested with a UPS, not optimistic.

RE: UPS for CoreOne L

I use this one Amazon Basice Line Interactive UPS one on my XL 5T and one shared by my MK3S+ and CoreOne.  They have saved prints during prolonged outages for me.  They are Line Interactive which means that they are continuously online and "conditioning" the power output so the switchover during utility loss is essentially instantaneous.  I just discovered that (in the U.S. at least) they are on a great sale as well.

Regards,

Steve

RE: UPS for CoreOne L

"Line Interactive" actually means the opposite - they're sitting idle and when the power goes out, they "interact" with the line and quickly switch the inverter on, so there's a brief interruption to the power.  But it's short enough that all properly designed electronics can handle it.

The continuously online ones are called "dual conversion" and are much more expensive, as they have a massive DC power supply that can handle the full load of the UPS plus battery charging, and they have a more robust inverter as it runs 24/7.  When the power goes out the battery stops charging and starts supplying the DC power, but the inverter doesn't notice and just keeps on chugging with zero interruption as there's no switchover delay.  Dual conversion units are pretty uncommon though because the multiple conversion steps waste some power and 99% of the time it's not needed.

They don't "condition" the line either, that's more marketing, all they do is have some MOVs to absorb surges and some of them have multiple taps on the transformers so they can feed say 200 Vac in and get 240 Vac out, to increase or decrease the output voltage if it goes out of range.  But they can only increase it in fixed amounts (e.g. 15 volts) and only across 3-4 different settings (e.g. +15, -15, +30, -30, +45, etc.)  It's pretty limited what they can do and living in a country with half decent mains power I think I've only seen it "condition" the line on one occasion when it reported the voltage being too low, but it boosted it from something like 229V to 248V, so it went from pretty much in range to a bit on the high side, which I thought kind of defeated the point.

I have had line interactive units for my home servers for many years, and APC in particular are really tough on batteries as they tend to overcharge them and kill them within five years.  They also pull a huge startup current from the battery when the inverter switches on, so it's common for the self test to pass without incident, but when the power goes out the batteries can't quite deliver enough oomph to start the inverter so the whole UPS switches off, defeating the purpose of the UPS in the first place.

I've had about 10 different APC units over the years and while they are solid chunky units, I've been put off them by the fact that you have to keep replacing the batteries every few years.

If I was going it again, I'd look at what the solar industry is using.  They sell home batteries that charge from the grid and provide AC power in an outage, and their batteries last for over a decade based on anecdotal stories.  They also sell just inverters (e.g. SMA Sunny Island) so you can build your own system from a DC power supply and inverter, and have a dual-conversion (always online) system that doesn't cook its batteries like an APC unit will.

Having said all that, the power supply in my Core One+ just outputs 24Vdc so rather than getting a full blown UPS, I'd probably look at providing backup power on the DC side as then you don't have to worry about an inverter.  You'd have to deal with protection and current limiting but essentially if you put a 24V battery pack in parallel with the PSU output then it should keep on chugging once the power goes out.  Not sure what that panic cable is for though, you might have to disable that in case it triggers a shutdown when the AC power goes away.

RE: UPS for CoreOne L

Posted by: @_kaszpir_

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

Posted by: @steve-5

I use this one Amazon Basice Line Interactive UPS one on my XL 5T and one shared by my MK3S+ and CoreOne. 

The specific challenge with the Core One L (which the OP wants to supply)  is its sensitive monitoring of the power quality. Apparently it is not happy with the output from many UPS types; they tend to trigger spurious alerts which stop the print. Hence, specific recommendations for UPS models proven to work reliably with the Core One L are required -- if such beasts exist.

RE: UPS for CoreOne L

Exactly as Jürgen said above, even if you find such a UPS that doesn't provide issues when providing wall power, it is less likely it will work correctly during the swap to using the UPS and/or back to wall power. 6-8ms response is still too slow. Simply, you can't use a UPS with the C1L at this time, unless Prusa makes some changes to AC bed controller to allow it work.

RE: UPS for CoreOne L

Regarding APC - I also had a few devices at work and privately and they were keeping the batteries in the expected lifetime (7y) or even longer ( got one that gets close to 10y now, but probably will need to change it this year). They all pass the battery test with the general 50% load just to be safe.  Nowadays those UPS devices are ancient, but they all work reliably for over 15y now 🙂 I guess I got lucky.

RE:

Anker Solix C2000 Gen2… can be used as a UPS.

I have mine attached to a transfer switch that runs against the AC in the wall and in the event of power loss within a few milliseconds it pops over to the battery pack.

it’ll be perfect for a core one L, and I’m currently using it on a Bambu H2C…

I should point out that I have an APC 1500 VA unit, and it only provides around 900 W and can’t handle the startup of the warming of a heat bed on a large format printer. the C2000 provides nearly 2000W… which can run the printer for a bit of time without any issue. and it certainly doesn’t have a problem delivering full power while the printer is warming up.

it’s lithium ion and the other ones lead acid and that’s the primary difference and it’s actually smaller than the 1500 VA APC (which is using 18 ah batteries; so not the small 1500 VA APC…)

RE:

Posted by: @gbmaryland

[...] it’ll be perfect for a core one L, and I’m currently using it on a Bambu H2C…

At the risk of repeating myself: If you have not tested your backup power supply on a Core One L specifically, you can't say whether it will be perfect or work at all on that machine.

It's not about raw power requirements -- the Core One L apparently uses very peculiar power quality monitoring and is not happy with the power supplied by many UPS systems. There will be some electronics to convert your backup battery's DC into 230V AC; whether it's output will be close enough to a sine wave to make the Core One L happy is anyone's guess.

RE: UPS for CoreOne L

It’s a full sign wave UPS… And the core one will probably not work properly with a stair stepped digital approximate sine wave. Both UPSes that I have do that particular kind of output (conditioned true sine wave) and it even works with the Honda 6500 IUS generator I have… since I happen to be an actual electrical engineer… there would have to be some very dirty conditioning riding on the sign wave for the core one L’s PSU to be THAT flakey.  If you really need me to I’ll pull out an oscilloscope and take a picture for you… 

RE: UPS for CoreOne L

You can see the live waveform footage starting around the 3:34 mark here:

RE: UPS for CoreOne L

I agree that "sign wave" sounds promising. But I don't think we have seen anything specific from Prusa regarding wave forms, small spikes or whatever it is that trips up the Core One L's power monitoring. And I don't think I have seen any report of success here on the forum (or elsewhere) where someone found a good UPS that actually works with he Core One L. Maybe the unsuccessful attempts all used cheap stepped-approximation supplies; maybe something more subtle is getting in the way?  

RE: UPS for CoreOne L

Yeah, Siri sucks for anything technical when I was driving at the time.