Angus had a roof that was not going to make this easy. Not a huge amount of space to work with, and he wanted the full package — solar panels and battery storage. The goal was straightforward: reduce his electricity bills, cut his grid dependency, and make sure every panel on that roof was earning its keep.
The challenge with a smaller roof is that you cannot just throw panels at it and hope for the best. Every panel placement matters. We carried out a full structural report and designed the array layout before we went anywhere near the roof, making sure we were squeezing maximum generation out of every square metre available.
| Component | Specification |
|---|---|
| Solar Panels | 9 x Canadian Solar TOPBiHiKu6 430W (3.87 kWp total) |
| Inverter | SolaX Power X1-MINI G3 3.68 kW string inverter with DC switch |
| Battery | Alpha ESS SMILE-B3-PLUS AC coupled (5.04 kWh usable) |
| Electrical | New 6-way 18th edition metal clad consumer unit |
| Protection | RCBO for RCD protection, SPD device |
| Metering | Bi-directional generation meter |
| Fire Safety | Fireproof board installed in garage |
| Certifications | MCS, Part P, EIC certificate, G99/G98/G100 DNO approval |
We went with an AC-coupled battery setup here. The Alpha ESS unit sits on the AC side of the system, which suited the existing electrical configuration and meant both the solar array and the battery could be monitored independently. It is not the most efficient coupling method on paper — DC coupling has slightly lower conversion losses — but for this property and this setup, it was the right call.
| Metric | Figure |
|---|---|
| Annual generation | 3,170 kWh |
| Self-consumption | 41% |
| Estimated payback | 6.77 years |
| Lifetime ROI | 225.2% |
| Previous annual bill | £1,261 |
3,170 kWh per year from 9 panels on a constrained roof. A payback period under 7 years and a lifetime return of over 225%. The bi-directional meter means Angus can see exactly what he is generating, what he is using and what he is exporting back to the grid.
This is a good example of what a well-designed smaller system can do. It is not about having the biggest array — it is about matching the system to the roof and the homeowner’s usage. Get that right and the numbers follow.
