I want to charge my electric car with my own produced green energy. How many solar panels do I need and how big should my home battery be?
After the installation of solar panels many people think about expanding and installing a home battery. An important consideration is whether the home battery is large enough and can be used to charge an electric vehicle (in the future). We get this question on a regular basis, and will therefore elaborate on it in this blog post. We show you what is possible when it comes to charging an electric vehicle with solar panels in a home environment.
With your solar panel installation, you will be able to charge your electric car to a certain to a certain level, sufficient for short daily trips. However, it is unlikely that you will be unlikely, however, that you will be able to be 100% independent when you when you completely drain the battery of your car every day and have to fully recharge it. and have to charge it again.
Below we explain how much you could charge from your solar panels, how many panels and home battery capacity are needed depending on the type of vehicle, and how type of vehicle, and how you will be able to charge more cheaply from the grid in the future. charge.
Solar energy for your home
A typical household in Flanders consumes approximately 8.3 kWh per day. To cover
cover this consumption, a PV installation will need to be about 3 kWp (10 solar panels).
should be large. You can also install a home battery of 3 kWh to 6 kWh to store part of that green energy.
kWh to use part of the generated green electricity at night. This way
you can store 25 to 75% of your own green power.
How much extra solar energy do I need to fully charge an electric vehicle? fully charge an electric vehicle?
The battery of an electric vehicle varies between 40 kWh and 100+ kWh. For example:
- The Nissan Leaf Acenta has a 40 kWh battery that gives you a driving range (WLTP) of up to up to 270km
- The Volkswagen ID.3 1st has a 58 kWh battery and can therefore achieve a range of 350 km. range of 350 km
- The Tesla Model 3 Standard Range Plus has a battery capacity of 50 kWh and an estimated range of 430km
- The Porsche Taycan 4S has a battery of 80 kWh and achieves an estimated driving range of 375km
So even to fully charge the Nissan Leaf, which has a rather small battery. fully charge during the day from your solar panels, extra solar panels are needed. A family would need about 15 kWp (50 solar panels) extra on top of the existing existing PV installation that covers the other electrical consumption in the house.
Please note that in Belgium, you cannot install more than 10 kVA of inverter power. So in practice it will be impossible for a private person to install this amount of solar panels. to install this amount of solar panels.
If you want to charge your electric vehicle at night, you need extra battery capacity to store the solar energy. To charge the same Nisan Leaf you would need an additional 40 kWh of battery storage. of battery storage. Just imagine what this would mean for a high-end electric vehicle. vehicle from the top segment.
So instead of charging your car from solar panels every
from your solar panels, you should in the first place try to recharge your car very regularly after your short trips.
to regularly recharge your car after your short trips. This
means that it is best to plug the car in whenever possible. This way it is
way it is feasible and you will possibly not even have to invest. Totally
nice when you do this in combination with a so-called 'smart' charging station
charging station, which allows you to give priority to your own solar energy to charge your car directly.
your car directly.
How much extra solar energy do I need to charge an electric vehicle daily? to recharge an electric vehicle every day?
Most people don't drive 270km a day (the range of the Nissan Leaf), or certainly not 430km (the range of the Tesla Model 3). This means that on a daily basis you only need to charge part of your vehicle's battery. on a daily basis. Statistics show that a car driver in Flanders drives on average drives only 20km/day. Let us assume for the sake of calculation that this would be 40 km/day. would be 40km/day. This means you would use 15% of the battery capacity of the Nissan Leaf would consume, which comes down to about 6kWh. For this you would need an additional 2kWp, or about 7 solar panels.
Below we briefly summarize what this means in different cases.
For example, someone who comes home at 6 p.m. and leaves again at 7 a.m. the next day and needs to top up with 8 kWh in that time slot (13 hours) will therefore only need an average charging speed of 0.6 kW. In this case, an 11 kW charging station is not necessary at all. And you need have no fear of the capacity charge that will be introduced in 2022.
Faster charging can and will of course sometimes be necessary, for example along motorways for those long trips you have to make a few times a year. a few times a year. Even at home, a 3-phase charge point of 11 kW can be useful for those few times when you don't have the whole night to recharge. to recharge at home. It is important to keep the charging capacity you are going to use at any given time as low as possible. that you are actually going to use at any given time as low as possible. This is in function of your moment of departure and the required amount of energy in your car battery for the route you have planned.
Renewable energy must be used in a well-considered way. In the future charging points will be rolled out in public places in our municipalities, at our workplaces, at shopping malls, along motorways. These charging points will be intelligently These charging points will be cleverly controlled in order to favour charging with surplus renewable energy and also to help stabilise the electricity grid. It is therefore important to look at the whole picture when considering the purchase of an electric vehicle. electric vehicle. Fully charging an electric vehicle at the highest possible speed speed is certainly not always the best or cheapest solution! solution!