To take advantage of pricing by 30 minute periods you will need a Smart meter and a Smart charger. Note that Tesla chargers do not have this capability as standard, and only the start time can be set.
Using Dynamic electricity pricing
This Ohme charger can obtain the cheapest rates of electricity available, as it receives 24 hours advance notice of the price for each 30 minute period.
It is possible to set the mileage required for departure and the time the car is to be ready by, the Ohme then selects which are the cheapest half-hour periods to charge the car. It also works with Amazon Alexa.
The mobile App can interface to the App for the car in many cases to obtain key information to operate even more effectively.