What you should know about charging your electric car at home | Part 1 |

Although I have written a previous article on charging cars at home now that the Spanish Minister of Industry, Commerce and Tourism, Mrs Reyes Maroto last week, has put down as deadline for the full establishment of electric cars establishing the year 2040 as a "prudent" goal that can be achieved and hence forbidding all combustion on that year, I think it would be a good idea to go again over the ins and out of having a charging point at home.


As a recap, on the the 14th of November speaking to the media in the Congress, Maroto has 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 pointing out however that in any case 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, 2032. The Netherlands, for its part, has set the year 2025 as its limit.

So sooner or later it seems that the future is electric, my friends. Therefore, here are some facts that may throw some light on the subject.


First thing 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 consider. The faster we want the load to be, the more we have to go into technical matters.

If we have a detached house with a private garage, we will surely have a 10-amp outlet, which would give a maximum of 2.3 kW of power. Before continuing, it is worth remembering a basic formula regarding electricity:

P = I x V, or power is equal to the product of the current (in amps) by the 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 of the intensity, since the voltage is "constant".

If you have a power of 3.68 kW, it means that every hour you can recharge a little less than 3.68 kWh, 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 kWh. 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 16 kWh. If we talk about the Nissan Leaf with the largest batteries (30 kWh), in those 12 hours we would not recharge even half, but would provide us sufficient for something more than 100 kilometres of autonomy.

The ideal is to have a specific recharge point, with 16 amps and 3.68 kW 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 regulation 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 a couple of afternoons to IKEA.

Rapid recharging points and superchargers have not been designed for home users because of their high cost. Its purpose is to solve specific mobility problems, they are not for regular and continuous use.

As I have mentioned in previous articles on electric cars, we can install a recharging point in a communal garage, informing in writing the president of the community, 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 be derived from the main meter to the user. It is advisable to consult with a qualified electrician, because this type of facilities can only be done by them. The cost depends on what needs to be done in each case.

In no case the community of neighbours will assume these costs so all expenses will be on us.


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