Use this Assistant in Off-grid systems that have AC-Coupled solar power: a grid-tie PV inverter connected to the AC out of an inverter inverter/charger.
Compatible with Multis, Quattros as well as Phoenix Inverters that have a VE.Bus connection.
Also use this Assistant for systems connected to the grid, that for a particular reason are not setup as ESS and therefor not using the ESS Assistant. Usually all mains-connected systems do need the ESS Assistant, and in that case do not also install the PV Inverter Assistant as well.
When the system is in inverter mode, this Assistant controls the output power of the grid-tie inverter by changing the AC output frequency of the system. A mechanism commonly refered to as Frequency Shifting. It does so to regulate the charge process: limiting the output power of the Grid-tie inverter to proper manage the charge and also prevent overcharge of the batteries.
This Assistant will be idle when the Multi or Quattro is connected to mains.
The Assistant will use the AC-output frequency to keep both the charge current and the charge voltage within limits.
To prevent DC and AC voltage overshoots because of varying solar irradiance and/or load fluctuations, it will limit the charge current already before battery voltage has rised up to the absorption voltage. It will derate the maximum charge current from 100% at 13.5 / 27 / 54V to 10% at 14.4 / 28.8 / 57.6V. These thresholds are not related to the configured absorption voltage.
Its locked to the upper limit because of a battery over voltage.
The frequency will reset itself automatically, in case one of the following conditions is met:
Alternatively, power cycle the system with the rocker switch on the front panel on the inverter/charger.
To prevent this from happening again, check your configured absorption voltage: setting it lower will prevent the overvoltage condition from happening again.