This Wimborne home now runs on its own solar into the evening and keeps the lights on in a power cut. A compact array, panel-level optimisers and a Tesla Powerwall 3 make the most of a roof with partial shading.
The home and the goal
The roof here is smaller and partly shaded at points in the day, so the aim was to get the most out of every panel rather than fill the roof. The homeowner also wanted the house to keep running if the grid went down.
What we installed
- 7 x Aiko 460W N-type all-black panels (3.22 kWp)
- A Tigo optimiser on every panel
- Tesla Powerwall 3 with 13.5 kWh of usable storage and a built-in solar inverter
- Tesla Gateway 3 for whole-house backup and energy monitoring
- Full bird protection around the array
Why we designed it this way
On a roof that catches some shade, one shaded panel can drag down the output of the whole string. Fitting a Tigo optimiser to every panel lets each one work independently, so a passing shadow only affects the panel it falls on.
The Powerwall 3 has its own hybrid inverter built in, so the panels connect straight into the battery unit. That keeps the installation tidy, with fewer boxes on the wall, and means solar, battery and backup are all managed by one system.
How it works day to day
During the day the panels power the home first, with any surplus charging the Powerwall. In the evening the battery takes over, so the home keeps using its own solar after the sun has gone down. The Gateway 3 watches the grid, and if there is a power cut it separates the home and runs it from the battery and panels.
The installation
Roofing and electrical work were done on the same day to keep disruption to a minimum. As with every DES job, the survey, design, installation and commissioning were all carried out by our own MCS certified team.
Questions homeowners ask about a system like this
Is a 3.22 kWp array big enough to pair with a Powerwall 3?
It depends on the roof and how the home uses power. Here the roof size set the array, and a Powerwall can also store cheaper off-peak electricity, so the battery earns its keep through the winter as well as the summer.
Does the Powerwall 3 work in a power cut?
Yes. With the Gateway 3 fitted, the Powerwall 3 provides whole-house backup and the panels keep charging it during the day.
Why fit optimisers on a small array?
On a small array every panel counts. Optimisers stop shade on one panel from pulling down the others.
Related reading
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Get a free quoteCall 01202 985 888Equipment details are from our installation records. Photos are of this installation and have not been altered.