How to choose a smart charger for your car and home

Do you actually need to install a charger?

When you buy an EV, chances are it’ll come with a charging cable that can be plugged into your traditional three-point power socket. It will do the job, but it’s slow. A three-point plug might be suitable for your needs if you only do a few short trips. However, it will struggle to fully recharge a battery overnight, especially in bigger cars with bigger batteries.

Why’s that? It all comes down to amps. Amps are a measure of current – like the quantity of water flowing in a river. Lots of current means more electricity is being delivered to the battery. Your standard plug delivers 10 amps. However, your car battery is designed to be charged faster than that. Charging your car with a standard plug is like filling a bathtub with a dripping tap – it’s doable, but why wait when you could charge three times faster with a dedicated 32-amp wall charger.

The convenience of buying smart

You likely use smart products for many tasks already – think about the products you connect to the internet and control using an app on your phone.

Buying an EV smart charger means you can easily set charging schedules to take advantage of time-of-use electricity plans and check charging progress from your phone. You can also specify what level of charge you want your battery to have when you start the day and make sure your charge never gets too low in case you need to unexpectedly pop out somewhere.

Some smart chargers go beyond apps and internet connectivity by connecting to the electricity grid, too. It’s these grid-connected chargers we are referring to when we talk about smart chargers in this article.

Why talk to the grid?

Our electricity grid needs to cope with charging an ever-expanding fleet of EVs. Once you start charging an EV at home, you can expect your electricity usage to increase by 20– -30%. Most EV owners charge during off-peak hours, but as our distribution infrastructure stands right now, if every home in Aotearoa charged an EV at 6pm, it’d cause problems. A bit like when you plug too many things into a circuit in your house and the circuit breakers pop, but on a regional scale.

There’s work required to upgrade the grid to cope with increased demand, but from a generation and electricity transmission perspective, the idea of connected chargers really appeals. It mitigates any risks like the hypothetical 6pm situation mentioned because the chargers can talk to the grid, receive messages that demand is too high and charge later when the peak usage passes.

It’s a win-win for EV owners and those that maintain the grid. If you own a smart charger that talks to the grid, it will only charge when it reads that demand is low and, with dynamic pricing that responds to demand, it’ll be cheaper too. To put a cherry on top, the low demand portion of the night is more likely than not generated from renewable resources like wind and hydro, and also, the grid survives the night.

If needed, you can also bypass all this grid chat and charge your car regardless, say if you know you’re getting up at 4am to start your road trip before the traffic builds and need to be fully charged to do so.

It’s about future proofing

Smart chargers that talk to the grid aren’t widely used yet, but investing in one now is a step in future proofing your home and automating your charging. A non-grid-connected smart charger won’t be able to distinguish between cheaper rates, it’ll just start charging at set times you programme in. That’s fine as the energy plans stand now, but change is coming down the line. A smart grid needs smart homes full of smart devices, and EV chargers are a good place to start.

Where to go for the smartest charger

Only some smart chargers talk to the grid and, at first glance, they all appear to be pretty smart.

Luckily, the Energy Efficiency and Conservation Authority (EECA) assesses EV smart chargers.

You can see the full list of smart EV chargers online, which is constantly being updated as more models are approved, head to eeca.govt.nz/smartchargers.

Safety first

An important reason for installing a dedicated EV charger is to avoid overburdening the wiring in your home. When you plug your car into a three-point charger in the garage, it will ask for the full amount of power the plug can give until the car is full of juice. If your garage plug shares a circuit with other power-hungry appliances like the laundry, you can put a lot of strain on the wiring – this can blow circuits and become a safety issue over time, as well as impacting the power supply to your house or potentially the wider area.

A registered electrician will be able to advise you on the state of the wiring in your home, what steps you need to take to protect it and whether your new charger should sit on its own circuit.

That’s not saying that the three-point plug should be thrown in the bin. It’s still a very helpful piece of equipment that you should always keep in your boot. It’s just that you should probably view this as a backup that you can use to charge a car in a pinch. The best practice is to install a wall charger.

Considerations for installing a wall charger

1. Away from hazards: Choose a charging spot that you can’t accidentally reverse your car into, so you don’t risk crushing your pricey new asset.

2. Easy access: If your charger is too high or low, you’ll struggle to read and operate the controls. Current guidelines have the mounting height of the display sitting between 1.2m and1.4m above the ground. You should also pick a spot without trip and safety hazards – so away from the doorway.

3. Able to reach both sides of your car: The unit needs to be positioned somewhere that the cable can reach both sides of any car in case your next one has a charging port on the opposite side.

4. Space for ventilation: Have a look around your garage now and take stock of any vacant wall space. Your new charger will probably have minimum spacing requirements for ventilation purposes, so be prepared to make room or get rid of some stuff.

5. Installing outside: If you have enough off-street space, you can mount an EV charger outside. But do not run an extension cord out under the garage to your EV, as this is unsafe. The charger and cable should be easy to access but out of the way when not in use – the last thing you want to hear is the crunch of the plug under your tyres when you finally arrive home in your post-work stupor.