Some research notes:

The bunnings video.

but I like this one.

and this. THIS.

Here’s how: https://www.androidauthority.com/set-own-music-mp3-custom-notification-ringtone-166052/

Simply Energy charges an average of 31.41 cents per kWh but you can choose flex pricing:

40.7 cents between 7 am and 11 pm, 22.4 cents between 11 pm to 7 am

This makes sense if you draw more electricity between 11 pm and 7 am then it makes sense else not.