Charging at home really is something of a deal-breaker, for the moment, when it comes to electric car ownership. With the cost of public charging high, and getting higher, it’s never been more important to have access to off-street charging and a charger strapped to the wall of your house or garage.
By charging at home, you’re opening up the potential of very cheap overnight charging, with electricity rates sometimes being as low as 11.3 cent per kWh, depending on your electricity provider and your tariff, you can potentially run a family-sized electric hatchback, for the average annual Irish mileage of 14,000km, for under €300 per year – compared to the €1,400 you’d have to spend on fuel for a conventional car.
Like we said, though, that does mean having a home charger, and here’s what you need to know when you’re thinking about getting one.
First, the obvious question – do you own your home or rent? If you rent, you’ll need to get the landlord’s permission before fitting anything.
RM Block
Then, you need to look at your electricity supply. The supply of electricity is pretty much universal to all houses in the country, but that doesn’t mean that the amount of electricity actually reaching your house is the same as every other house.
A home car charger draws 7.4kW when it’s operating, which doesn’t sound like much, but consider the following: according to the Sustainable Energy Authority of Ireland (SEAI), an average house can cope with a total power demand of 65 amps, or about 14.7kW if you’re on a normal 230-volt power supply.
Which sounds fine – 7.4kW is only half of that demand – but then you remember that a power shower can draw as much as 10kW when switched on, or an electric oven as much as 5kW, and suddenly you’re crossing that power demand threshold. Do that, and your trip switch will trip, and everything will shut down.
Because of all of this, it’s important to get your house surveyed to check that your electrical installation can cope with the extra load demand of a car charger, and you may want to get a priority switch fitted, which can divert power to the area that’s most needed, instead of throwing the trip switch.
It may be worth getting your electricity system upgraded to an 80-amp load, which would give you more than 18kW to play with. Incidentally, this is another good reason to charge at night – you’re less likely to be running the oven or shower, and you’re actually doing more good overall, as your car’s battery will be soaking up wind-generated electricity that might otherwise go to waste.
You’ll also need a smart meter to take advantage of the best electricity tariffs, and that will also allow you to benefit from your car’s vehicle-to-load function, which can, in the event of a power cut, allow you to power your home from the car’s battery, depending on the model.
Now that the power and the meter are sorted out, you’ll need to get the actual charger. So how much is that going to cost you?
According to leading charger supplier Ohme, the cost of a standard home charger installation is either €1,249 or €1,299, depending on whether you want a “tethered” charger, with its own integrated cable, or an “untethered” one which you use the charging cable supplied with your car. A tethered charger may not seem worth it, but it does make for faster connection and disconnection when the rain is coming down, so bear that in mind, although there have been reports of charging cables being cut (when not in use, obviously) and stolen for their valuable copper cores.
There’s a €300 grant from the SEAI for getting a home charger fitted, so in both cases that cost falls to just under €1,000. You don’t have to claim that – the charger supplier will claim it on your behalf. You just need your MRPN meter number and your address. It also helps if you send over some photographs and possibly a short video of the area where you want the charger installed, so that the installer knows what they’re dealing with ahead of time.
Just bear in mind that if the charger is some distance away from the location of your electricity meter, you may need some additional cabling, and while the cable itself isn’t very expensive at all, you might need to dig a trench for it, which needs to be 40cm deep if it’s under grass, and 60cm deep if it’s under a solid surface, and that can add to the cost of installation.
Ohme and others can provide smart chargers that automatically detect when electricity is at its cheapest and start charging. Most chargers can also be remotely controlled via an app. Usually, you can also instruct your car to start charging via its own control app, and you can monitor its charging progress the same way.
How quickly will you recoup all this money? Well, taking just the charger and its installation in isolation (and not rolling in the cost of the car, insurance, etc), the circa-€1,000 installation cost will be recouped within the first eight months of electric motoring, assuming you’re covering that average 14,000km annual mileage. You’ll get it back faster than that if you have home solar panels, but that’s possibly a tale for another day.
