What is Solar Only and how does it work?

In this article:

• What Is Solar Only?
• How does it work?
• What is the minimum power that needs to be produced by the solar panels?
• Does this mode use your ready by time?
• Graphs
• How do I enable Solar Only?

What Is Solar Only?

Solar Only mode matches the charge rate of the EV to the amount of solar power being exported to the grid. This allows customers to entirely self-consume their solar power. If there is not enough solar power being produced then charging is paused until there is. This gives users the ability to charge with zero cost, zero-carbon electricity.

How does it work?

To enable users to charge with only the solar power they are producing, we vary the charge rate of the vehicle to match the power produced. We can do this in two different ways;

1. Users with a hardware-based solution have a CT Clamp installed around their meter inlet. This lets the charger see the amount of power being imported or exported to the grid. This means that household load is taken into account as we are looking at the total power going into or out of the house.
   
   
2. Users without any hardware installed can use our software-based solution. We use a solar irradiance forecast which provides an estimation of the solar power produced by a solar array.

Using this information the charger can vary the amount of power available for the vehicle and so ensure that no energy is imported or exported. Both of these solutions will allow users to have zero cost, zero carbon charging however a hardware solution will typically be more accurate.

What is the minimum power that needs to be produced by the solar panels?

Your solar panels need to be exporting more than 1400w to the grid for your car to charge. If they are producing less, then no charge will go into your car. This means that the total power produced minus the household load needs to be greater than 1400w

Does this mode use your ready by time?

This mode will ignore your ready by time and will only charge when there is enough solar energy. This means that the vehicle might not be ready by when you need it. If this is the case, you can switch to Solar and Grid which will top up your car from the grid if there is not enough solar power, and make sure you are ready for your ready by time.

Graphs

A real Solar Only session with an Indra EVSE. You can see how the charge rate is modulated to ensure that import/export is as close to zero as possible.

Please note, we do not currently take into account household load. We assume that all the energy produced by the solar panels goes straight into the car. This can also lead to some grid imports as there might be some energy used by other appliances around the house.

How do I enable Solar Only?

1. Head to the Smart tab and select Solar
2. Turn on Solar smart charging and select Solar only