8kW solar panel and battery installation in Penylan, Cardiff

The story of this install

An east–west roof

Andrew's semi in Penylan has no south-facing roof. Its two faces point east and west, both at 30°. That's no bar to solar: it just spreads generation across the day, with the morning sun on one side and the evening sun on the other.

We split 16 JA Solar 500W panels evenly between the two faces, 4kWp each and 8kWp in all, with a GoodWe 8kW hybrid inverter and two GoodWe batteries for 10kWh of storage.

East–west systems also tend to produce a steadier, flatter curve through the day than a single south face, which means more of the solar gets used in the house as it's made and less needs storing.

A car on the drive

Andrew already had an electric car, and his bills were running at around £110 a month. A few weeks after switch-on we spotted that his car charger was drawing from the battery. Working with GoodWe, our team moved the sensor that tells the system what the house is using, so the battery now serves the home instead of emptying into the car.

Install day

The photos here were taken on installation day, with the scaffold up and the panels going on. The system was commissioned the same day, 15 April 2026, and MCS certification and network approval were sorted for him.

In Andrew's words

Andrew's review says it best: “Easy to deal with and the added luxury of having a showroom to visit.”

Before switch-on we tested the system, set up the GoodWe app and went through it with him. Andrew can see what each roof face is producing, how full the batteries are and what's going to the car.

Yearly generation is the MCS estimate made for this home before installation, using the standard MCS method. Real output varies from year to year with the weather.

Full kit list

Panels

16 × JA Solar 500W (8kWp)

Inverter

GoodWe 8kW hybrid inverter

Battery

GoodWe batteries, 10kWh

Roof

Tiled roof, 30° pitch

Paperwork

MCS certificates (solar and battery), DNO approval and handover pack