Intelligent charging

The idea of our Smart Charging is to shift charging processes to times of lower grid utilization. The additional load on the electricity grids caused by the increasing number of electric cars in Germany is a much-discussed topic. With our home charging solution, we offer the right product for precisely this challenge. We charge your car as standard during the night, when the electricity demand of industry and households is low. You still have the option of immediate charging: simply by pressing a button in our app (more on this under point 5).

We would like to ask you to refrain from using vehicle-side settings to control the charging process. Otherwise, our wallbox may want to charge when your e-car does not allow it and vice versa. Unfortunately, this means that two fundamentally good approaches cancel each other out. Settings on the vehicle side include amongst other things

• Intelligent Charging / Smart Charging
• Battery-saving charging

Plug-in hybrids (PHEVs) and pure battery electric vehicles (BEVs) have different electricity (kWh) and power (kW) requirements in most cases. PHEVs have smaller batteries and thus require fewer kWh for a full charge. They also often only charge single- or two-phase with a maximum of 3.7 or 7.4 kW. New BEV models, on the other hand, can mostly charge three-phase with up to 11 or even 22 kW. This fact raises the question of whether smart charging for PHEVs makes sense. In the German electricity grid, a significantly higher grid utilisation can be observed in the hours after work than in the night hours between 10 pm and 4 am. For this reason, we are shifting the charging processes that would otherwise occur between 4 pm and 10 pm in the night. From our point of view, it makes sense to shift all charging processes in our pool here and not make an exception for PHEV models. After all, these also have a large share of the additional grid load in the overall view. If individual drivers then want or need to charge at an earlier time, they can do so without the process being prevented by grid congestion.

Here you will find another illustration that should make the two variables “electricity demand” (consumption) and “power demand” more tangible.

For a better understanding, you will find the visualisation of the time windows below. According to this, all charging processes that should be started between 4 p.m. and 10 p.m. are shifted into the night by default. This means that charging processes only start from 10 p.m. at the earliest* and then end in the early morning or even in the middle of the night, should the car already be fully charged. If you need your vehicle at an earlier time, you can press the “Power Charge” button in your smartphone app at any time.

This is how it works: Charging processes between 4 p.m. and 10 p.m. are shifted into the night.

Charging processes between 4 p.m. and 10 p.m. are postponed into the night.

Why do charging processes start at 10 p.m. at the earliest and not exactly at the start of the smart window? This is because not all 24 quarter hours (equivalent to 6 hours of 4 quarter hours each) of the window are usually required for the charging process. It therefore often makes sense to start charging processes later in the night.

As soon as you plug your car into the wallbox at home, the button “Activate power charging” appears in your app. This button becomes relevant if you want to charge your car as quickly as possible and cannot wait until the following morning. By pressing the Power Charge button, the postponement of the charging process is cancelled and your car is charged immediately.

Info: If your vehicle is not plugged in, you will not be able to find this button either. So don’t be surprised if it is temporarily not visible.

Please understand that this illustration is only available in German.

In the past, push notifications from the vehicle app to start/stop charging processes were sometimes triggered because Smart Charging is subject to scheduled interruptions in the charging process. You can therefore consider deactivating these push notifications in your vehicle app in your smartphone.

The ageing of lithium-ion batteries results from two processes: ageing over time and ageing due to charging. The ageing due to charging processes is actually negligible if the following conditions are met:

• At the start of the charging process, the SOC (battery level) is greater than 20% and at the end it is less than 80% → avoid marginal areas.
• Small cycles are charged, e.g. from 30% to 50% SOC, instead of large spans, e.g. from 20% to 80% in one go.
• The charging power is less than 0.5 C. 1 C means that a car with a battery capacity of 64 kWh is charged with a charging power of 64 kW (64 / 64 = 1). Accordingly, in this example, charging would have to be done with a power of less than 32 kW to stay below 0.5 C. The maximum possible 11 kW therefore corresponds to only 0.17 C.
• In fact, ageing over time is often the dominant factor in battery ageing (provided the ageing due to charging remains low). It can be said that battery ageing is greater…
• the higher the ambient temperature (but not below 0 °C)

• the higher the SOC (battery level)

So a lithium-ion battery ages much faster if it is left outside the house in the sun at 40 °C with a full battery. In the garage and with a SOC of around 30%, on the other hand, the battery is protected. You can also say that the later the battery reaches a high SOC before the vehicle is used, the better. This is even encouraged by our smart charging. Ideally, in the future (if desired) there will also be the option of entering the departure time so that we can bring the car to the desired state of charge as late as possible. Aging due to charging processes also tends to be positively influenced by our smart charging.

The right charging profile also needs the right measuring technology in the background. This small communication unit, which we connect to your meter if possible, enables the ¼ hourly recording of electricity consumption. Only in this way can other players on the electricity market know how much electricity was and is needed and when. This is the only way that transport and energy transition can merge and consumers can make their personal contribution. Your household electricity meter will remain unaffected by us. You can continue to choose the electricity supplier of your choice privately and are not bound to Mer. The SMGw will also become an issue for private households with an electricity consumption of less than 6,000 kWh per year in the foreseeable future. The mandatory rollout of this metering technology for larger consumers is already in full swing.

In order to better understand and classify the necessity of our efforts, we only need some basic knowledge of the electricity market. This market is defined by the size of the interconnected electricity grid, in our case the European interconnected grid. Electricity is consumed and generated within this grid. A simple rule applies: supply and demand must be in balance at all times.

In the past, our electricity landscape was characterised by consumption-oriented generation. Primarily fossil-fuelled power plants were regulated up or down according to demand. However, this has changed over the years to a supply-dependent electricity landscape. This means that electricity is no longer produced according to prevailing consumption patterns. It is now produced primarily whenever the sun shines and/or the wind blows. This is because electricity cannot be stored on a large scale, as is the case with natural gas, for example. Consequently, the challenge of the energy transition is to consume electricity whenever it is available. Electric cars are for the most part still charged precisely when they are connected to the charging station. The fact that they are usually only needed again at a much later point in time with an (almost) full battery has hardly been taken into account so far. Mer is tapping into this potential and thus creating a sensible link between the transport and energy transition: The e-car becomes a flexible consumer. With our solution, you charge exactly when the electricity is available and the grids are not already at their capacity limits.