When generating an API Token from the Tesla servers a refresh_token is also returned along with the normal token used to retrieve data from your vehicle.
This refresh_token can be used to automatically generate a new token before the original token expires, and ensures that data logging will not be interrupted. Ten days before your token expires TeslaFi will try to obtain a new token using your refresh_token.
This feature is optional and can be enabled by checking 'Automatically Renew Token' when generating your next token in the setting page of TeslaFi.com. The token section will also display 'Auto Refresh On' when this feature is enabled.
Your tesla.com login credentials are never saved by TeslaFi.com.
Customer support service by UserEcho