What you should know about charging your electric car at home
Although I have previously written an article on charging cars at home, last week the Spanish Minister of Industry, Commerce and Tourism, María Reyes Maroto issued a deadline of 2040 for the full implementation of electric cars, saying that it is a ‘prudent’ goal that can be achieved, hence forbidding all combustion vehicles in that year.
On this basis, I think it would be a good idea to revisit the ins and out of having a charging point at home.
As a recap, on November 14 speaking to the media in the Congress, Maroto stressed that the executive’s proposal on the future law on climate change and energy transition is a draft, a ‘working document’ that is being analysed, but pointed out, however, that it is ‘an urgent matter’.
Maroto also pointed out that other countries such as France and the United Kingdom have marked the same goal of 2040 and that Germany, with great weight in the car industry, has a more ambitious horizon of 2032. The Netherlands, for its part, has set 2025 as its limit.
So sooner or later it seems that the future is electric, my friends. Therefore, here are some facts that may shed a little light on the subject.
First things first
Recharging your vehicle at home is a great advantage of the electric cars, both for convenience, for the environment and of course cost.
Electric cars can be charged in any socket that has certain technical characteristics (starting with earthing), but there are some small considerations to bear in mind. The faster we want the charge to be, the more we have to delve into technical matters.
If you have a detached house with a private garage, you will surely have a 10-amp outlet, which would give a maximum of 2.3kW of power.
Before continuing, it is worth remembering a basic formula regarding electricity:
P = I x V, or power is equal to the sum of the current (in amps) multiplied by voltage.
For example, with 16 amps and 230 volts we get 3,680 watts, or 3.68 kilowatts (kW). The speed at which an electric car is charged depends on the load power, and this in turn on the intensity, since the voltage is ‘constant’.
If you have a power of 3.68kW, it means that every hour you can recharge a little less than 3.68kWh, since there are small losses to be considered in the process. For every full hour, multiply by 10 hours we will have loaded something less than 36.8 kW. Ok so far?
Electric cars can have either a small charger for occasional use, or a specific connector for charging points designed for that purpose. In some cases, the occasional charger is sold separately and is not included in the equipment.
The usual socket versus the rapid charging point
The occasional charger is not as fast as the specific charger, and it can work really slowly. For example, if it works at 6 amps, we would need 12 hours to reach 16kW. If we talk about the Nissan Leaf with the largest batteries (30 kW), in those 12 hours we would not recharge even half, but it would provide us sufficient energy for something more than 100 kilometres of autonomy.
The ideal is to have a specific recharge point, with 16 amps and 3.68kW of power
Depending on the installation, there will be some modifications to the electrical circuit. The thickness of the cables, for example, is a factor to be taken into account.
The law that regulates all this is called TC-BT-52, from the Spanish Low Voltage Electrotechnical Regulation, approved last year. All installations must be carried out by qualified personnel; it is not something that one can do by going to IKEA a couple of times.
Rapid recharging points and superchargers have not been designed for home users because of their high cost. Their purpose is to solve specific mobility problems; they are not for regular or continuous use.
As I mentioned in previous articles on electric cars, we can install a recharging point in a communal garage, by informing the president of the community in writing, as defined by Law 19/2009, of measures to promote and streamline the rental and energy efficiency of buildings. In the case of needing a secondary meter, the approval of the community of owners is also necessary.
Depending on the case of each, a separate meter will be installed (sometimes with a second contract) or a line will come from the main meter to the user. It is advisable to consult with a qualified electrician, because these types of facilities can only be installed by them.
The cost depends on what needs to be done in each individual case.
In no circumstances will the community of residents assume these costs, so all of the expenses will be the responsibility of the person initiating the installation.