Can a Solar Panel Charge an EV on a Cloudy Day?

Solar panels and cloudy conditions

The UK weather can be unpredictable, with downpours and overcast days being a common occurrence. Investing in a domestic solar system allows you to generate your own green energy, but is it a worthwhile investment for EV drivers given the weather?

More than 1.3 million households in the UK already have a solar system, which is an increase of more than 150% in the last 10 years. It’s undeniable – consumer confidence in solar panels is growing, as demonstrated by the rising uptake. Considering we experience regular overcast weather, with regions in Scotland, Wales and Northern Ireland being some of the cloudiest in the country, it’s worth exploring whether a solar panel system can power an EV charger even on the dreariest of days.

Can you use solar energy when it is cloudy?

Yes, you can use solar energy when it’s cloudy, although the capacity to generate electricity will be reduced. When direct sunlight is covered by light clouds, solar panels produce around 24% less energy than they do on clear and sunny days, and around 67% less on very cloudy days. Still, that’s enough to generate some clean, renewable energy to charge your EV with solar power.

You can read more about using solar panels to charge an electric car in our guide.

Can you generate solar energy in winter?

Absolutely, you can generate solar energy in winter, just like any other time of the year. The only difference is the number of sunlight hours during the winter. Solar panels don’t work at night, because they need direct or indirect sunlight to make electricity. The sun is out for fewer hours in the winter months when compared to summer, meaning you simply have less opportunity to generate electricity.

Snowfall and rain are common in the winter months, and they can reduce the amount of electricity a solar system produces by up to 50%. On days with very heavy rain, the capacity to produce solar energy can be cut by up to 90%. However, in the UK, these conditions are not the norm and on most days, there is usually enough light to generate energy.

Domestic solar panel systems are made to withstand and work in harsh conditions. If it snows heavily, most snow will slide off panels thanks to the slight incline and residual heat they will have from operating.

How to generate more solar energy

Many modern solar panels are able to effectively convert sunlight into green energy even on a gloomy day, as long as the sun hasn’t set. If you choose solar panels with concentrated photovoltaic cells, you’ll be generating more solar energy than a lower rated panel of the same size.

While most domestic solar panels are one-sided and fixed in position, there are also systems that can adjust their position to maximise direct sunlight, therefore improving energy generation. Bifacial solar panels have photovoltaic cells on the front and back of each panel, meaning they absorb more direct and indirect arrays. Plus, solar panel systems with tracking are available to adjust the angle of panels and follow the sun’s trajectory for maximum light absorption throughout the day. These options come at an extra cost, which is something you should consider when comparing different options.

What is a solar battery and how can I use one?

Solar panels are an excellent source of renewable energy, but any unused electricity from a domestic solar system will usually go to waste or be fed into the grid without a storage battery. Normally, when solar power is produced, it becomes available and has to be used immediately. If your EV isn’t plugged in while the panels generate energy, a storage battery allows you to store the solar power until you need it.

Having a storage battery in addition to solar panels is especially useful for EV drivers, because you may be away from home throughout the day, i.e. most sunlight hours. The majority of electric car owners charge their vehicles at home overnight when solar panels don’t work. A storage battery can solve this timing issue by storing any solar power that went unused, so you can plug in and charge to your schedule.