Doing it in the middle of the night would have problems because some people still have plug in alarm clocks.
The least disruptive time would be the early afternoon on a work day.
Not for those who work from home and then if there are any delays in completing work you begin to run into one of the time of days when there is more demand for power meal time.
And whilst I do have a plug in alarm clock I also set the alarm on my mobile phone just in case power fails.