Domestic Battery Retrofit to ‘Rent-a-Roof’ Solar PV.
Many properties have ‘free’ solar that was fitted when the Feed in Tariff existed more than 10 years ago. These systems can be optimised for the homeowner with the addition of a battery which ensures as much of the free electricity as possible is used in the home.
Project Overview
This family home in Newark, Nottinghamshire had ‘free’ solar panels fitted 12 years ago. To take full advantage of the solar energy generated, it’s important that as much of this energy as possible is used in the home. This property now has a battery system which stores surplus solar power and automatically feeds it back to the property when required. This takes full advantage of the solar energy and can provide a solid return on investment.
Existing ‘Free‘ Solar Panels
Sometimes referred to as a ‘rent-a-roof’ scheme, the homeowner benefits from free electricity while the system owner (in this case ‘Shade Greener’) takes the feed in tariff payments, a subsidy which ended to new entrants back in 2019.
For this project the home owner wants to take full advantage of the solar panels so any surplus power is stored rather than exported onto the electricity grid. The existing solar panel system needs to remain untouched, so McConnells Green fitted an AC Coupled Solis Inverter with a 5kWh Dyness battery.
Inverter & Battery
The inverter is a Solis AC coupled Inverter, AC coupled means that the inverter operates independently of the solar inverter and is perfect as a retrofit to enhance an existing system. The battery is a Dyness Lithium Iron Phosphorus (LiFePO4) model which has a long lifespan, high output, is eco friendly (no cobalt) and safe.
System Specification
- Inverter Specification
Solis RAI 3k-48ES-5G AC Coupled Inverter
- Battery Specification
Dyness B51100
- Battery Total Capacity
5.12kWh
- Battery Usable Capacity
4.1kWh
- Existing Solar Panels
Estimated 3.5kW Shade Greener
Annual System Performance
- Existing Electricity Consumption
3131 kWh
- Predicted Increased Usage
1136kWh
- Predicted Energy Independance with Battery
66%
End Result
- Installation Cost
£3,366
- Co2 Reduction
255Kg / year
- Total Savings
£341 / year
Conclusion.
This system monitors solar generation and when there is surplus power, this energy is stored in the battery. When there is a shortage of power in the property, the battery supplies the shortfall. This takes full advantage of the existing solar panels and leads to a substantial reduction in the homeowners electricity bills and can be a very low cost investment.