What solar surplus is
When your solar installation produces more energy than your home is consuming at that moment, that excess (surplus) is normally fed to the grid in exchange for a credit on your bill.
How it is redirected to charging the car
With the right configuration, that surplus can be prioritised to charge the electric car instead of being sold to the grid, making use of energy that would otherwise be credited at a lower price than what you pay to consume from the grid.
What you need to do it
A solar installation, a wallbox compatible with surplus management and, in some cases, an additional meter that informs the charger of the available energy in real time. We configure it as part of the combined installation.