Hybrid system – Solar grid connect with battery back-up

Coburg, Victoria

  • System Design: October 2012
  • System Installation: December 2012
  • System Commissioned: December 2012

Client: John Levy

Project Goals

Design, supply and install a hybrid system (Solar grid connect with battery back-up) for a household. The installation was coordinated during the house renovation.  


  • Roof-mounted photovoltaic array consisting of 16 x 170W Schott PV panels
  • 12 x 2V 770Ah BAE solar gel deep cycle batteries
  • Custom built battery and control gear cabinet
  • Selectronic SP Pro 3kW 24V interactive inverter/charger SPMC240-AU
  • Kaco Powador 3002 solar inverter
  • Complete system documentation including maintenance schedule and log sheets.
  • PV System size: 2880 Wp
  • Battery capacity: 24V 770Ah
  • Average Load = 7kWh/day
  • Estimated Average Solar Output = 10kWh/day
  • AC coupled configuration
  • Australian made SP Pro inverter custom programmed to run off battery during night and only use grid power if the battery state of charge reduces to a programmed set point.
  • During the day, if the generated solar power is not sufficient to supply household loads, the SP Pro will automatically provide the required power from the battery or the grid. The percentage of power from each source is also fully programmable.
  • One of the SP Pro relay outputs was set up to turn on a warning LED light in the living room to let householders know when the grid power goes down and the house is running on battery back-up (otherwise the power switchover is instant and would not be noticeable)
  • Switchboard modifications made to have only essential loads on battery back-up