There is no phrase called "electric miles". However, there is a unit of measurement called "miles" which refers to a unit of length used in the US and UK, equivalent to 1.60934 kilometers or 1760 yards.
Sentences with «electric miles»
This bumps up the number of electric miles you can replenish to 11 to 13 miles in an hour. (plugincars.com)
Your all - electric miles per charge will really add up. (nissanusa.com)
To facilitate the use of these charging stations we need to have some guidelines so we can avoid conflict and maximize electric miles driven. (evworld.com)