This common winter phenomenon is usually caused by low solar battery temperatures. Most lithium-ion solar batteries, such as Sunsynk, need to stay above ~12.5°C to charge at their full rated speed. If your solar panels are generating power faster than your battery can charge, the excess has nowhere to go but out to the grid.
Thankfully, our milder UK winters are extremely unlikely to ever push your panels to -40°C or below. With that being said, extended freezing temperatures could lead to temperature-related degradation that causes slight physical changes in the panels’ materials. Over time, this can lead to permanent damage – though not in the best solar panels.
Extremely cold temperatures can cause freezing, which can damage sensitive components within the panels. It’s essential to understand that solar panels don’t necessarily need hot weather to function; they need sunlight. So, even in cold climates, optimising their exposure to sunlight becomes crucial.
In winter, solar panels can generate some of the electricity needed to heat a house, but you’ll still need to buy some electricity from the grid. You can use your solar panels to lower your heating bills if you have a system that runs on electricity, like a heat pump, electric boiler, or solar diverter.
Your solar panel output will typically be lower in winter. During these months, the days are shorter and the sun stays lower in the sky – meaning your panels will receive less daylight and less direct sunshine. However, your solar & battery system will benefit from the colder weather.
Similarly, watch for any tree branches or other foliage that could block light from reaching your solar panels. Keeping your trees and bushes in check will allow your solar panels to absorb as much sunlight as possible, even as the days get shorter. Winter is coming, but that doesn't mean your solar power generation needs to suffer.