Our system recommendations depend on the following factors: 1. whether you want standard domestic Single Phase (230V) backup or 3 Phase (400V) backup; 2. your required system size– solar system size (kWp), charge/discharge rating (kW) and storage capacity (kWh); 3. whether or not you have already installed. For single phase the best systems are Tesla's Powerwall 2 and SolaX Power's X-Hybrid inverter range combined with their Triple Power batteries. Solar panels produce DC electricity. DC is also used to charge the batteries. DC electricity produced by the solar panels can therefore be charged directly to the battery with minimal losses. DC electricity is only converted to AC. DNO permission is currently required for any battery system that will operate in 'island mode', regardless of size. Battery inverters must be certified to G98/G99 standard as for solar inverters. G99 fast track applications (for. A typical Powerwall 2 installation schematic is as follows: The solar inverter is separate to the inverter/charger contained within the.