What is ESS
ESS is short for Energy Storage System. It is a combination of standard multipurpose Victron products, setup with an ESS configuration. In the system, there must at least be one inverter/charger and also the Color Control GX.
When to use ESS
Use in a self-consumption system, a backup system with solar or a mixture of both: for example using the top 30% of the battery capacity for self-consumption, while keeping the other 70% available as a backup during a utility grid failure.
At times when there is excess PV power, the PV energy is stored in the battery. That stored energy is then used to power the loads at times when there is a shortage of PV power.
The percentage of battery capacity used for optimizing self-consumption is configurable: set it to 100% for (Western Europe / Germany). Or for locations with frequent, or even daily, grid failures, set the threshold to 80%. Only the top 20%
Keep batteries charged:
Besides using (part of) the battery for self-consumption, the system can also be configured to always keep the batteries charged. Failures of the utility grid are then the only moments when energy from the battery is used to power the loads (backup). Once the grid is restored, the batteries will be recharged with power from the grid, and ofcourse also solar when available.
When not to use ESS
Inverter priority, also known as intentional islanding or Ignore AC input systems.
With and without grid-meter
ESS can both be used with an external grid-meter, and without one.
With grid-meter, a full or partial grid-parallel system.
Without grid-meter: All loads connected to AC-out. And in case of PV Inverters, also connected to AC out.
Optional feed-in of MPPT Solar charger power
Power from an MPPT can be fed back to the grid. Enabled/disabled by a user setting on the CCGX: Settings → ESS.
Fronius Zero feed-in option.
By using the Power Reduction feature in Fronius grid-tie inverters, the system can automatically reduce the output of the PV Inverter as soon as feed-back is detected; without switching and frequency shifting.
It is not possible to combine ESS with the Fronius Smart Meter; it is not necessary either, since ESS already has metering.
With ESS, it is not possible to disable feed-in a system with other brands of grid-tie inverters.
Backup system with Solar
All loads are wired on the output of the inverter/charger. The ESS mode is configured to ‘Keep batteries charged’.
When using a grid-tie inverter, it is connected to the output as well.
While the mains is available, the battery will be charged with power from both the mains and PV. When available, loads are powered from PV.
Feed-in is optional, and can be enabled or disabled depending on local regulations.