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What is the difference between an AC-coupled and a DC-coupled battery storage system?

An AC-coupled battery storage system takes the alternating current from the (domestic) grid and converts it into direct current for charging the batteries. When the batteries are discharged, the battery direct current is converted back into alternating current for the (home) grid. When converting mains current into battery current and back again, losses occur in the battery inverter. Typically, between 10% and 15% of the energy is lost as waste heat in the inverters.

Advantage: An AC-coupled battery storage system can also be installed after the PV system has been built. Disadvantage: In total, up to 20% of the PV energy is lost, because in addition to the loss of the battery inverters described above, there are also the losses of the PV inverter. The PV inverter converts the direct current from the PV modules into alternating current, which is then used to charge and discharge the batteries via the battery inverters. Here, too, losses of a few percent occur between the PV modules and the AC grid.

A DC-coupled battery storage system avoids these conversion losses and converts the direct current of the PV modules directly into direct current for charging the batteries. When discharging the batteries, the battery direct current is converted into alternating current for the grid as before.

Advantage: Lower conversion losses and seamless operation of the PV system even without an AC grid. Disadvantage: Is usually only possible with a new PV system.

The salidomo© can be operated as an AC-coupled battery storage system, as a DC-coupled battery storage system or even a combination thereof.


Which products can be used to charge the salt batteries via DC?

All Victron solar charge controllers can easily charge innovenergy's salt battery storage systems. The charging power is limited to 6 kW for the salidomo© and to 12 kW for the salidomo© EXT. 

The solar charge controllers from Studer Innotec also work, but cannot be read out and are therefore not displayed on the Victron web platform.