Residential – Karaka – Mixed 125&290W with Hybrid Inverter and Batteries

Case Study

This was an unusual project in that it involved a mix of both the 125Wat and 290Watt products. The owner had enjoyed the benefits of a Solar array on his previous home, had recently purchased an Electric vehicle, and was keen to incorporate battery storage into the design of his new home; consequently, he was motivated to utilise as much of the available roof space to maximise his Solar generation.

The roof on this project was a Metalcraft ‘espan470’ roof that had multiple roof planes of varying length. In all we installed 18 x 125Watt & 30 x 290Watt strips resulting in a 11.04kWp array. The 290W strips were positioned on the North facing roof, and the 125W strips were on the west roof. In the case of the west facing roof, the strips were offset from centre to mitigate afternoon shade cast by the standing seams of the roofing.

In normal circumstances all the cabling is concealed under the roof flashings which eliminates the need for any penetrations associated with the Solar cabling, and to provide weather protection; but in this case it was necessary to utilise a mid tray mounted cable tray flashing in one area where the strips needed to extend beyond the wall to roof flashing. However, because this system uses clamp mountings and Colorsteel flashings to match the roof colour, it blends into the overall roof nicely.

This rooftop array was also complemented by an innovative modular lithium-ion battery solution from BYD that consist of multiple 1.28kWh units that stack atop one and other like a beehive. The output of the rooftop array was large enough to warrant a battery capacity of 11.52kWh. The advantage of this modular battery system against other larger standalone battery solutions is that it can be expanded progressively over time if desired. This allows the home owner to start with a modest battery capacity and then monitor the actual energy generation and consumption patterns collected by the monitoring software over a period of time so as to avoid over investment in surplus battery capacity; this also allows clients to spread the capital investment over a period of time if required.