I have an old multi running on a thin supply from the micro grid of the main house inverter/charger.
It has its own battery bank and is mostly powered from bluesolar 50 and smartsolar 30 chargers.
The AC load is predominately a multi-speed pump. The regular duty cycle is covered happily by the multi and solar, along with other DC loads.
Occasional high load is a bit more tricky, and seems to be required more frequently.
The pump has a poor power factor, as expected. ~ 0.65 constant load and worse if working hard.
I looked at installing a motor run capacitor to improve the power factor, but local electrician is reluctant as he says it needs a different capacitance for each speed. I thought it could fix at low speed/load, and help at high speed. He is thinking about that.
I suggested he could install one for low speed and I could use the Multi or Cerbo relay to engage another when they detected higher load or poor pf. He was even less impressed with thinking about that idea.
I would also like to add (repurpose) a small AC coupled system to the multi, to reduce load on the inverter and draw from the microgrid when pump is heavily loaded and possibly allow some other discretionary load to be turned on when solar generation was good. It would cover low speed running on sunny days, so potentially periods of battery charging, export to microgrid, and lower load for the multi.
A short test with generation about equal to multi load, showed it to cause much worse power factor with real power flowing back to the micro grid, and high draw on the batteries, presumably, to provide the reactive power for the pump. Multi was very confused.
Any clever ideas, beyond replacing the multi with something more powerful ?
Does anybody know of residential/small grid inverter range that do dynamic pf correction ?
I have only heard of large scale commercial inverters that can do this.
Some grid inverters claim to provide fixed leading or lagging pf, but at least here in Australia, they are now all required to generate Vars in response to voltage. I don't know if they can still be set to fixed Vars. Maybe something no longer certified for grid, or second hand. Not as good as dynamic, but maybe better than unity pf?
Any experiences with AC-coupled inverters generating Vars into the multi load ?
