My house battery starts to feed into the grid when the printer or the heating bed is on. so seems that the inverter does not like.
Probably the regulation of the inverter is slower than the bed.
Does anyone know the “frequency” with which the bed is regulated?
I don’t know if this is healthy for the inverter in the long run or if you can just ignore it. it’s annoying that electricity is “sold”, but because of this I don’t want to invest in HW again which prevents this.
Yes, there is some sort of regulation. I think it’s more PTC than PWM. I measured the power draw decreasing as the bed heated up. Since you are in Europe, I’ll comment that the bed draws about 900W on 240V, compared to 300 or so on 120V. This is more likely the reason for the battery issue.
The Bambu technicians responded quickly and provided me with the necessary information:
The full CE certificate and the relevant information that the bed operates at 1Hz.
I can put together the situation so far that the inverter also works with ~1 Hz but not synchronously with the printer. the “current” is always there when the printer does not need it. so it goes into the power grid.
The question is whether this is unhealthy for the inverter or just a cosmetic problem. (apart from the fact that energy is wasted).
my neighbor is an electronics dude and said an EMI line filter could help. Theoretically, but the capacitor must be large enough?
edit:
ah… I owned some DIY 3d printers and they also had a 230V heating bed. There was no problem.
The switching times of the PID control were more sluggish.
