The main event today was the start of the installation of the Tesla PowerWall 3 solar inverter and battery storage system, to connect to the solar panels which were installed in August. Much of the work was in the outdoor GRP cabinet, which houses the Backup Gateway that is responsible for taking the site “off grid” in the event of a mains supply outage – so it pretty much has to be installed adjacent to the main meter. Earlier measurements had confirmed there was just enough room for it inside the cabinet.

The main PowerWall 3 unit, which is a combined inverter and battery storage unit, was always destined for installation in the Plant Room, which is (intentionally) the nearest part of the building to the GRP cabinet. In order to add further storage capacity there will be two battery expansion packs – although only one was installed today, due to space and weight limitations on the installers’ van.

While installing the Backup Gateway, mains power was disconnected from the House for almost 5 hours, which was far too long for the Uninterruptible Power Supply in the House to continue powering the IT network equipment and CCTV cameras, resulting in the 12:00 webcam snapshot which is normally automatically uploaded as the daily overview image being missed – so the 11:00 snapshot was manually uploaded instead.

There was also further progress with the groundworks – although somewhat delayed by the mains power being off, meaning that the pump that was going to be used to clear the water from the drainage trenches couldn’t be cleared until power was back on after 3pm.

The long-awaited concrete headwall – the replacement for the one that was due yesterday but got damaged in transit – was delivered, although with some difficulty using the small-ish digger on site. It turns out this was far from a direct replacement for the one that was ordered, since it is sized for a 450mm diameter pipe, not a 150mm diameter pipe – and it has the wrong specification of protective grid on the outlet.