How many solar panels do I need to charge an EV?
Many people are already using solar panels to power their homes, yet the concept of charging electric vehicles (EVs) with solar energy remains relatively unknown. In this article, we aim to demonstrate that not only is it possible to use solar panels for car charging, but it also presents a very advantageous option from both economic and environmental perspectives.
How do solar panels work?
Solar panels use photovoltaic (PV) cells, which absorb energy from the sunlight, creating electrical charges. The movement of these charges creates a direct current and sends electricity to a solar inverter, which converts it to an alternating current that can be used in the building, stored in a battery system, or sent to the National Grid (if you have more than you need). Solar panel installations come with an inverter as standard.
PV cells are placed between layers of materials with semiconducting properties and connected together to form a solar panel. Multiple solar panels connected together are known as arrays.
Can you charge an EV with solar panels?
Yes, home solar panels can indeed charge an electric car. To achieve this, you will need two key components: a photovoltaic (PV) installation and an electric vehicle (EV) compatible solar charger. This setup allows the electricity generated by the sun, which is converted by the panels, to be transferred to the car. Additionally, incorporating a solar PV battery into your system enables you to charge your car even during the night.
Can you use solar panels to charge hybrid cars?
Yes, hybrid cars can also be charged using the electricity produced by solar panels, and the benefits are comparable to those of fully electric vehicles. If you wish to charge your hybrid car overnight, you will similarly require a solar battery storage system. Alternatively there are cheap overnight rates from energy providers targeted to EV owners who can then charge directly from the grid overnight.
How do solar panels charge an EV?
Solar panels can connect directly to an EV charger. However, not all EV chargers are able to use electricity generated from solar panels before it’s used to power the house. This issue can be solved by using an EV charger which:
- Can use the solar-generated electricity first;
- Comes with an app where you can choose whether the EV or the house receives the solar-generated electricity.
If you charge your EV overnight you’ll also need a battery to store the electricity produced during the day. If you have an EV charger set up before installing a solar PV system, be sure to check with your EV charger manufacturer to see if any settings need to be changed on the EV charger to acknowledge the new solar PV system, and to avoid any downtime on your charger.
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Are there any differences between charging an EV with a PV system in summer and in winter?
It's evident that the electricity generated by the sun and converted by solar panels relies on sunlight levels, which fluctuate with seasons and weather. In summer, solar power can often cover your car's charging needs, but in winter, you may need to top up with electricity from your provider. Despite occasional reliance on grid power, the savings from solar energy remain significant compared to traditional charging.
How many solar panels do I need to charge an EV?
Generally between eight and 12 solar panels are required to charge an EV. However, the figure can be affected by factors like:
- Which EV you have and its mile range and battery size. Bigger batteries take longer to charge.
- How many miles you drive.
- The sort of roads you drive on (frequently driving at high speeds will reduce the battery life quicker, for example).
- The way you drive (a smooth driving style is better for battery life).
- How much sun your solar panels get.
- The wattage of the solar panels.
It's crucial to emphasise the significance of geographical location, as the calculation of the number of solar panels required can vary. For instance, in Brighton and Hove, where the annual kWh generated per panel is 1230, the situation differs from Birmingham, where it's 1020.
What you should know, however, is that the typical household solar PV system can produce between one to four kWp. This means that it's possible to fully charge an electric vehicle equipped with a 40 kWh battery in just over eight hours.
If you’re getting solar panels installed, you can work with your installer ahead of time to make sure your system is capable of producing enough energy to power everything you need.
If you already have solar panels, your system might only produce enough energy to power your home and not charge your EV. Contact your provider to find out how much it’s capable of generating.
What EV chargers are available?
EV chargers compatible with solar panels:
- Wallbox Pulsar Plus, which has solar integration as standard and an app which allows you to schedule charging times. It’s one of the smaller chargers available, taking up minimal space on your outside wall, and the LED status ring tells you when it’s charging.
- Zappi, which has eco charging modes that use electricity generated by your solar panel system but can also use power from the National Grid. The eco charging modes adjust the power depending on what’s being used elsewhere in your home, and can be controlled from the myenergi app. It requires at least 1.4kWh, so your solar panels will need to produce more than this in order to charge your EV and provide energy for your home.
- Hypervault Home, which has solar integration as standard and allows you to switch between energy sources if needed. A handy app lets you decide whether to charge using 100% solar power or a mix of power sourced from solar and the National Grid. LED lights tell you what mode the charger is in at a glance.
- Indra Smart Pro, which diverts surplus solar energy to your EV for charging. It has three charging modes, off-peak charging, and LED status lights. You can schedule charging times using the app, and input your tariff to get the cheapest charging option and monitor how much you’re spending on energy if you use anything from the National Grid.
- Rolec Wallpod, which comes in a simple, plug-in charger and a smart version which is connected to the ev.energy app, gives you more control over scheduling your EV’s charging sessions, and is available with solar compatibility. There are two charging speeds to choose between: 3.6kW and 7.2kW.
Is it possible to use a regular EV charger?
Yes, you have the option to use a standard EV charger with solar panel charging. However, you'll need to include a PV inverter unit, which converts solar energy into usable electricity. This setup allows you to charge your electric vehicle directly using the power generated by solar panels.
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Why charge an EV with solar panels?
The primary reason relates to cost. Charging your electric car with your own solar panels is a more economical option than using electricity from your utility company or even using public electric vehicle charge points.
Another reason is convenience: if you have a photovoltaic installation and a solar battery, you can charge your electric car both during the day and at night, enhancing your energy independence.
Things to take into account about charging your EV with solar panels
If you decide to use photovoltaic panels to charge your car, you should consider the following aspects:
Space and number of solar panels installed:
To ensure your PV system provides sufficient energy to meet your electricity needs, it must be well-adjusted, taking into account the specifics of your roof, shade, or the potential presence of trees or other elements that might affect its performance.
It's crucial to thoroughly analyse all the circumstances and characteristics of each situation before making a decision.
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When and how often would you like to charge your electric car:
If you plan to charge your electric car overnight when the solar panels don't generate electricity, you should consider having a storage system that will enable you to complete the charging process whenever necessary.
On the other hand, the duration of the charging process depends partly on the size of the battery and the parameters of the charger, so you should select the models that best fit your needs and habits.
How long do solar panels take to charge an EV?
It can take between half an hour and 12 hours to charge an EV with solar panels. This significant variation in time is caused by different EV battery sizes and charger speeds.
Pros and cons of using solar panels to charge an EV
| Pros | Cons |
|---|---|
| Solar power is an environmentally friendly source of energy. While an EV is a more sustainable option compared to petrol and diesel cars, you might still use a non-renewable energy source to charge it. Solar power removes this barrier and reduces your carbon footprint. | Solar panels still work when it’s cloudy, however production may not be optimal which highlights that on their own, solar PV systems cannot provide 100% predictable electricity. Production can be affected from day to day and hour to hour by weather. You can minimise this unpredictability by investing in a battery. |
| You’ll save money over time. Using solar panels for energy costs less than using energy from the National Grid. It costs less to run an EV than it does a petrol or diesel car, and even less if you’re using solar panels to charge it. | You must factor in the cost of buying and installing an EV charger. |
| Being able to charge your EV at home overnight is more convenient than trying to find a nearby charging station during the day. | It can take longer to charge an EV using solar power than it can using power from the National Grid. (This can be solved by charging your EV overnight.) |
While the number of solar panels needed to charge an EV can vary, it’s worth looking into. Using solar energy for charging can lower running costs even more and it’s an excellent alternative to the National Grid for those looking to reduce their carbon footprint.
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Final thoughts
The installation of solar panels on your property offers a compelling solution for homeowners and electric vehicle enthusiasts alike. Harnessing the power of solar energy for charging not only leads to savings on electricity costs but also plays a vital role in preserving our environment. Ready for your EV charger? Don't miss out on our guide to selecting the right EV charger.