Wallbox: Saving money through efficient charging

Charging batteries more efficient

Charging batteries. A process which repeats itself day after day. Every owner of an electric car knows it well. The Mobility House might not be able to get rid of this process for you, but we can help you to get as much benefit from it as possible. Daimler explains on its website how important it is to charge batteries properly in order to use electric cars efficiently, citing the smart fortwo electric drive as an example. According to the automobile manufacturer, the consumption of the CityFlitzer depends on whether the battery is recharged via a domestic socket or a wall box after the journey. As we know this subject has many benefits for you, the user, our masterminds have put their heads together to come up with an explanation for you.

Our explanation on the efficiency of a wallbox

Julian, our technology nerd, knows that a wall box is more sustainable than a domestic socket. He explains that the key factor here is not energy consumption, but how the current flows through the battery. The benefits of a home charging station lie in the higher levels of efficiency as a result of charging with a higher level of power. This is caused by the following two processes:

1. A rise in total efficiency

When the battery in an electric car is charged, additional systems are activated, such as the battery monitoring function, for example. The energy consumption of these elements does not depend on the charging power and is exclusively proportional to the charging time. Wall boxes shorten the charging time and subsequently also decrease the amount of energy needed for ‘additional loads’.

2. A higher level of effectiveness with a higher load

Energy loss is at its lowest when you are charging with a large amount of power. This is due to the fact that the effect of the charging device, and therefore the ratio of current to maximum charging power, depends on its load. The level of effectiveness is also clearly poorer with a small load than it is with a maximum load.

You can save a lot of money by charging an electric car with a wallbox

According to Daimler, the smart fortwo electric drive consumes 14.3 kWh, rather than 15.1 kWh, over 100km if it has been recharged with a wall box. In other words, you would be consuming about 6% less energy per journey if you used the wall box. This would have a major effect on your wallet over a long period of time, as this graph shows.

So viel Geld sparen Sie beim Laden eines Elektroautos an der Wallbox

Here is the reason why: according to ADAC, a person in Germany makes an average 3.4 journeys a day, which usually amounts to 11.5km. This amounts to an average trip to work of 17.7 km and a training route of 8.1 km. If you reconcile this information with the price of electricity, which amounted to 29.13 cents per kWh in 2014 and rises by 3.4% on average every year, with the 6% saved per journey, it is easy to see how much you can save over a given period of time. For instance, a working person can save € 165 in 5 years, € 360 in 10 years and € 591 in 15 years.

It’s best to work out for yourself how much you could save with a wallbox!

The Mobility House has created the following formula in order to work out how much you can save over a given period of time. In the first step, we work out the average ADAC value with the savings from a charging station in comparison to a domestic socket; using the smart fortwo electric drive as an example, this would be 0.8 kWh / 100km (15.1 kWh – 14.3 kWh). In the second step, we multiply this by the average electricity price of the next five years, and are subsequently able to work out the amount saved after 5 years. In order to find out how much you have saved, you only have to input your own annual mileage in our finished formula:

Annual Mileage x Amount Saved to the Charging Station = Amount Saved per Year

Amount Saved per Year x 5 (years) x Average Electricity Price of the Next 5 Years = Amount Saved in 5 Years

This is what our formula looks like for a working person:

(3.4 Journeys per Day x 17.7 km per Day x 220 Working Days per Year) x 0.008 kWh= 105.92 kWh
105.92 kWh x 5 x 0.3118* = 165.13 Euros

* based on the current electricity price of 29.13 cents/kWh and a rise of 3.4% per year

The right wallbox installation for the most efficient usage

Another reason for the sustainable effectiveness of home charging stations lies in proper installation. If the electric installation is not set up for specific charging, the level of loss rises. For instance, common domestic sockets are not equipped for long periods of charging with a high load. This means that recharging electric cars can bring unwanted consequences. For example, cables which are too thin can overheat or lead to burning. In order to avoid these risks, Daimler recommends wall boxes. We have also put some tips together for you, which you need to consider when installing a wall box.

Use the opportunity of a wallbox for your electric car

The Mobility House are specialists when it comes to wall boxes. Experts like Julian deal with specialist subjects every day in order to always stay ahead of the game. For this reason, we develop solutions which not only aim to fulfil demands for charging an electric car, but which also take your individual needs into consideration. We have put together a further article for you regarding the things you need to take into account when buying a charging station.