Websocket FTW!
The EVCC server supporting websocket communication - This allow the server to push data-updates as they happen, which makes polling the data by the integration obsolete.
Important
The new new communication layer, is disabled by default - if you want to support the development, I would kindly ask to go to the configuration of the integration and enable the websocket support by checking Use Websocket (experimental) - Polling Interval will be ignored. After a short while the Integration should be reloaded in HA and the integration will listen to the websocket of your configured EVCC server.
If you don't want to try the new feature - the update 'should' not harm your current setup.
Note
After the initial stuff has been implemented and is working fine in the past 2 days, I have learned something additional today about how HA can handle/work with web sockets. This have been reflected now in the update [make use of coordinator.async_set_updated_data(...) once data have been received via the web socket]
If you have issues when enabling the new feature, please create an issue in the repository and disable the Websocket support in the configuration of the integration.
Also would be quite nice to get feedback, when the websocket will work for you :-)