Yeah that’s a no for me. I was fine with my 4 P1S and having them run at the same time, but hearing my UPS screaming for help due to overload, isn’t in my plans specially since I don’t want to trip the circuit multiple times. I’ll be returning my P2S for this reason.
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Have you actually checked though? This sounds like the exact same behaviour as the A1, where the heater is mains connected (thus why it is slower on 120, faster on 240, but with higher wattage draw). And when heating to 65c, it (A1) does heat up in about/under 20 seconds, and starts from pretty much when the printer starts downloading the job. I’m not say it is faster, or better, just it’s not doing “nothing”. P1S is slower to warm up the bed, but doesn’t draw as much current… you don’t get something do nothing 
This is an awesome idea! I’m toying with the idea of using something as simple as that, or something with a relay as well inline or as a plug. I have worried about a relay/plug with something like a printer in case of relay failure or accidental open. Having it be simply a meter obviously removes an risk of a relay opening unintentionally.
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That was my fear as well, this energy meter does not have any relais. On the other hand I use a relais switch for a home server 24/7 and never had a problem since 5+ years…
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I will admit, my fears in using relays are completely without merit LOL I have a PDU that has controllable outlets that I haven’t ever had a problem with, and numerous things on smart plugs that I’ve never had a problem with, yet I worry about a relay opening mid print for some reason… nobody accused be of being completely rational!!
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I will admit I didn’t open the printer up and connect voltage and amp meters to each component. And I agree it is doing something, which I believe is simply a self test as it only spikes for about 5-10 seconds (corrected form previous post). When I say it is doing nothing, i am referring to no intrinsic value to the printer or the print. It’s simply self test as nothing else is happening to perform any real value to the time or quality of the print, therebuy it can be dialed back via firmware. Take a look for yourself.
I’'l upload the video in a moment, Got sidetracked.
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I am going to start by hooking up a Zooz Zen14 outdoor rated dual plug, so I can connect the AMS 2 and the P2S to their own monitored outlets, and monitor that, could be interesting… will see as the P2S is still en route with an ETA of Friday
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Realized that the Zen14 does not actually do power monitoring, so got a couple Zigbee power monitoring plugs coming
As long as they are decent quality units, you should be fine… I’ve been using relay switched outlets for several years now, all controlled via Home Assistant, and no issues with “false” turn off / turn on events. Worst that happens is they seem to go offline periodically… not sure if it is a wifi or configuration issue, but they always come online again and it never affects the power of unit they are monitoring/controlling.
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I was thinking of something much more simple… did you actually look at the screen of the printer at the same time as the power monitor, to see what was actually happening… as I was just looking at the power consumption of my P1S on 240V, and it is pulling 1200W for a brief period just after the print download is starting… which is in conjunction with the print bed warming up from ambient to ~50C… in about 15-20 seconds, followed by ~300W pulses, which then drop off to less than 200W when printing…
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We must always remain cautious with regard to these measuring instruments which only give a point value at a time T. We can therefore have an erroneous reading over a short period of time. Only an oscilloscope will give a true measurement.
Otherwise, 10 years ago a heating plate took 2 to 3 minutes to painfully reach 100°. BambuLab equips its P2S with a much more powerful plate in order to shorten printing times. In fact, it is remarkable that you never have to wait for the plate to be hot to start printing. This is progress despite the disadvantages of the inverter which often will not follow. You can’t have everything without putting up with the downsides. Our washing machine does the exact same thing to heat water quickly and no one complains!
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The spike happens every time the printer starts up, which I agree is probably for the bed heating up. However, the prints I have tried between the P1S and P2S take almost the same time to print - within seconds of each other. Of course the longer the print time the less advantage there would be.
The big downside is the load on the Electical system. On a 15A circuit, which is the most common in a US household, two P2S printers would overload a single circuit as they draw 16.8 amps at startup combined. You could get three or four P1S printers on that the same circuit. If you had a small print farm that would mean calling an electrician to add more circuits. Of course staggering your print starts would mitigate the surge somewhat, but you should still never purposely have the possibility of an overloaded circuit. For instance, you wouldn’t put two washing machines on the same circuit.
So, while a surge to the print bed might have a minuscule advantage for print times, it has a significant and unnecessary down side in my opinion. An option to reduce that initial surge would be a welcome update.
This is why I hate LED lights. Most are not rectified and flicker a lot from the AC current (which I am very sensitive to) while incandescents (due to their simplicity) NEVER flicker. Cheap LED lights lack a smoothing capacitor and will show any “unclean” power by flickering from (as you said) uneven current draw. The flickering can also be amplified if the wire gauge on the circuit powering the LED lights and the printer is a bit small and causes more voltage sag than normal. I used to have this same problem when we had different lights and a Ender 3 Pro. With my P2S, I don’t see any flickering as our newer LED lights have better rectification. Still hoping to score a ton of BR30 incandescents for cheap for our basement at some point though for better CRI.
(sorry for my rant and nerdy talk)
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I just wanted to add to this post, just in case Bambu reads it.
PLEASE ADD LOW POWER MODE TO THE P2S!
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I second this request!
It just needs to not spike to 1kw for the first few seconds. It uses the same power as the P1S after that. As you can see from the image, the spike lasts under 5 seconds and then levels off. I can’t think of any good reason for this.
Using the 80% rule, you cannot attach 2 P2S printers to a 15a circuit. It also means you probably shouldn’t have anything else on that circuit.
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Um, 80 percent rule is for continuous loads for long periods of time. 3+ hours. The 1000W load is essentially a transient load during the heat bed warmup. According to your app, lasting about 20 seconds. I have smart outlets on all my printers and once heated up they run around 100W for pla. I can run 4 printers and my instrument bench in a 15A circuit, just have to be careful of how I startup the printers.
Printers are 3x X1C and 1x P2S. Another 15A circuit is running an H2D and 2x P1S. The H2D spikes high as well.
that’s funny.
“low power mode” for a 3d printer lol
on the other side the world is demanding faster heating etc
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Similar story here, my P1S pulls solid 4.2A @240V from mains when AC heated bed is heating up. And pulsing 0.5A to 1.5A while printing.
That picture was taken during Ozzy winter, voltage drops down to 230V at night when neighbours turn on heaters.
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It is not best practice to have 4 inductive loads that can simultaneously spike 3X the rated capacity on the same circuit. If these were built in loads, it wouldn’t pass any code that I am aware of. I understand you stagger the starts, but that doesn’t change the formula.
That said, I completely understand your point. I was only trying to point out that there is no need for this 5 second spike. The startup sequence could be half that and still accomplish the same thing, as the P1S clearly proves.