EV BATTERIES EXPLAINED

A battery is like the fuel tank for your BEV. Here’s what you need to know

There’s a remarkable increase in the number of battery electric vehicles (BEVs) being registered in New Zealand and with the new Clean Car rebate scheme, they are more appealing than ever before.

While demand is increasing, many motorists are still unfamiliar with the technology, including the batteries used to power them.

It’s important to understand three main aspects of the BEV battery: capacity, charging capability and range.

CAPACITY

A BEV’s battery is rated in kilowatts per hour (kWh) — a measurement of electricity for the amount of energy expended in 60 minutes by one kilowatt of power. So, the more kWh the battery capacity has, the longer the vehicle can go on a full charge.

For example, a 2021 Nissan Leaf has a 40kWh battery and an approximate range of 270km, whereas a 2021 Hyundai Kona Electric II has a range of around 484km thanks to its 64kWh battery.

Essentially, the larger the capacity, the bigger the price, and the further you are able to travel on a single charge. This shouldn’t be confused with the power rating of the electric motor, which is measured in kilowatts (kW). The power of the motor is what produces the impressive torque demonstrated by BEVs.

CHARGING

There are three main methods for charging a BEV battery available in NZ. Depending on your needs and the capacity of your BEV, you may need to install the infrastructure to charge your vehicle at home. Manufacturers may even include this in the price: Mazda is offering early adopters of the new MX-30 a free fast charge AC Wallbox Pulsar Plus ( installation is extra).

1. Home (via an InCable Control Box (ICCB) charging cable)

This is designed to connect to a standard three-pin wall socket. It’s an overnight charging method and will fully recharge a used Nissan Leaf in six to eight hours, or a new Hyundai Kona Electric in around 28 hours. The power supply from this cable is typically 10amp/2.4kW.

2.Home (via a fast charge wallbox)

This is an optional “wallbox” for your household and improves charge times by using a 16-32amp,

3.7-7.4kW (or up to 22kW with

3-phase) power supply. It can significantly reduce charging time but can cost $4000-$5000 to purchase and fit. It needs to be installed by a registered electrician and compliant with regulations.

3.Public rapid charging stations

This is the fastest way to charge a BEV, taking up to 75 minutes to charge a large capacity BEV from

0-80 per cent, typically utilising

25-50kW DC charging.

There are websites such as ChargeNet that help you find your nearest charge station. The AA also helps locate charge stations

through its time and distance calculator — aa.co.nz/travel/ time-and-distance-calculator

In Wellington, the AA has introduced a mobile breakdown van fitted with a BEV charger to support members who are caught short on their journeys. In 20-25 minutes it enables enough charge to drive up to 10km, so members can get home or to a nearby charging station. If the Wellington trial is successful, the AA will look

at expanding the service.

RANGE

Two common phrases you might hear when shopping for used BEVs are state of charge (SoC) and state of health (SoH).

State of charge (SoC)

SoC is defined as the available capacity in ampere hours (Ah) and expressed as a percentage of its rated capacity.

State of health (SoH)

SoH is a way to judge how much life a used BEV’s battery has remaining. It gives overall condition of a battery, not its current charge. For some vehicles, on-board diagnostics may provide data that will help you determine how much longer you can expect it to last. For example, the Nissan Leaf displays how many bars the car will charge to out of a possible 12.

When buying a used BEV, SoH is often more useful that the mileage travelled — even a lowmileage BEV can have a poor SoH rating.

An ageing BEV battery can reduce in ability to store charge while the demand from the motor’s power remains the same. This means that a full battery charge won’t last as long.

New BEVs tend to have a fairly extensive battery warranty. The most affordable BEV in NZ — the MG ZS EV — offers an eight-year/ 160,000km battery warranty.

Can BEV batteries have a second life?

When a BEV battery no longer provides a usable driving range, it may be possible to have it refurbished or replaced.

In some instances, it might be possible to replace the dead cells within a battery. If a full replacement is required, you may be able to improve the range of your BEV by installing a new battery with more capacity, as is the case with some Nissan Leafs.

Used batteries still have value. They may be refurbished, repurposed or recycled for uses like storing electricity from solar panels at home.

The AA is on the governance group of the Battery Industry Group (BIG) together with EECA and Vector. BIG is a collaboration between more than 170 businesses and individuals across energy, waste, transport and battery sectors tasked with designing a solution for reusing and recycling large batteries commonly found in BEVs or stationary energy storage.

In May 2021, BIG submitted a proposed product stewardship scheme for large batteries to the Ministry for the Environment.

For more information on BIG and sustainability within the AA, visit aa.co.nz/sustainability