Home Car Charging Station: One EV Home Charger or Two?
More Christchurch driveways now have two electric cars. Here is how to charge both without a bigger supply, from one shared charger to two units that split the power.
The Rolleston Driveway With a Leaf and a Model Y
A Rolleston family had a Leaf for the school run and a Model Y for the commute into town. They assumed they needed two chargers and a bigger supply. Their new board had room, but their 63A mains also carried two heat pumps, an induction cooktop and a hot water cylinder.
We looked at how they actually drove. The Leaf did 30km a day and the Model Y did 70. One 7kW charger, with a tethered cable long enough to reach either bay, could fill both cars on alternate nights with time to spare. They chose that, saved the cost of a second unit, and the car with the emptier battery gets the plug.
Three Ways to Charge Two Electric Cars at Home
| Setup | How it works | Best for |
|---|---|---|
| One charger, swap cars | A single 7kW unit with a long tethered cable that reaches both parks | Households where one car does low kilometres |
| Two chargers, shared power | Two units on one CT clamp, splitting the spare supply between them | Two daily commuters who both need a full battery every morning |
| One charger, one portable cable | A wall charger for the main car and the other car's own cable on a socket | A second car that only needs the odd top-up |
Two-charger setups need units that can share one load-management sensor, such as Evnex or Wallbox. We price the second unit on the same written quote.
Getting One Charger to Reach Two Cars
- Mount it between the two parks rather than at one end
- Choose a tethered model with a 7.5m or 8m cable
- Fit a cable hook so the lead never lies on the ground
- Set the app to charge only inside the night-rate window
Where Two Chargers Go Wrong
- Two chargers with no load sharing on a 63A supply
- Two different brands that cannot talk to each other
- A second circuit squeezed onto a board with no room left
You Probably Do Not Need a Bigger Supply
Two 7kW chargers running flat out would want about 64A between them, more than a typical 63A supply can spare. In practice they never need to, because load management hands them whatever the house is not using and both cars still finish overnight. Load management can save $1,500 to $2,500 against upgrading the mains.
The load management guide shows how the sharing works as the house gets busy.
Price a Charging Setup for Two Cars
Four photos are all we need: your switchboard with the door open, the spot where the charger will go, the path between them and your meter board. One written number comes back, usually the same day.