Some wallboxes reduce or suspend charging at high temperatures. Direct sunlight can contribute, but a temperature warning can also involve plugs, connections or other installation conditions. Follow the manual for the exact model and have recurring faults checked by a qualified electrician.
Air temperature, enclosure surface temperature and internal electronics temperature are different measurements. A surface reading alone cannot explain charging derating. Wind, orientation, materials and charging duration all affect the outcome.
A suitable shield can create shade without enclosing the wallbox. Keep the manufacturer's clearances, ventilation and access to controls and cable. Crystal Shell shields from above and in front; it is not active cooling or a guarantee of a particular temperature reduction.
Tesla's Universal Wall Connector manual describes temperature-related limitations and checks. That example concerns the specified model for North America, not every wallbox. Always use your own model's manual.
Tesla — Universal Wall Connector
Before ordering
Check the exact model, width, height and depth, mounting points, socket, display, doors, cable route and bends. Keep the operating space and manufacturer-required clearances free. The cover’s outer dimensions do not automatically equal the usable internal space.
Wallbox and charging cable are not included. The shielding is additional and does not change the wallbox’s IP rating.