EV Charging Calculator

Calculate the cost and time to charge a battery-electric vehicle at an AC charging point.

How to use

The calculator will estimate the cost of AC charging, speed, and kilometres of range delivered for most battery-electric vehicles in New Zealand.

This is useful when home charging or for caravan parks and motel owners to estimate the time and cost of charging customer EVs.

What is charging efficiency?

The proportion of electrical energy stored in the battery during the charging process.

Charging losses may result from AC to DC energy conversion, heat loss, and the normal power loss that occurs in the transfer of electricity. In addition, some EVs will use mains power to heat or cool the battery (prolonging battery life).

Charging loss means more energy is supplied than what ends up in the battery. Typically, slower charging speeds (i.e. 10A) and colder temperatures result in more charging loss.

Usable battery capacity

The charging amount and time are based on the EV’s usable battery capacity.

Unfortunately, not all car manufacturers publish this information; some list total battery capacity, some don’t state whether usable or total, and some don’t list any battery capacity information. For some EVs, these specs are estimated.

Time to charge

AC charging speed is mostly consistent, although it may slow down as the battery reaches capacity (e.g. from 95%).

Thanks to Will Hunter (of Better NZ Trust) for input on how motor camps (etc.) might assess EV charging costs.