Fact check on electric car myths: battery, charging time and safety
There are many myths surrounding e-mobility. However, many of them have long been outdated. We answer the most important questions in the FAQ on electric cars.
- Stefan Porteck
(Hier finden Sie die deutsche Version des Beitrags)
Electric cars are no longer a novelty, yet many specifications about them are no longer up to date. This may cause uncertainty for some. Our answers clarify the most important questions about e-mobility.
Charging options
What are the options for recharging?
The emergency charger with shock-proof plug supplied with every vehicle charges the vehicles at the usual socket. However, the socket and its wiring must be designed for such a continuous load, which should definitely be checked by an electrician beforehand. The vehicles are usually charged with 2.2 kilowatts at the earthed socket, with a maximum of 3.6 kilowatts - a full charge takes several hours to more than a day with current battery capacities.
(Bild: Andreas Martini)
The somewhat better and faster alternative is charging with alternating current at a wallbox. However, many vehicles can only be charged with 7 or 11 kilowatts. For an additional charge, you can get rectifiers that can accept up to 23 kilowatts of alternating current (AC). AC charging also plays a role at free chargers or at holiday resorts far from the main roads.
Charging with direct current (DC) is called fast charging. Because of the complex charging infrastructure, it only takes place at public charging stations. Here, as well, the weakest link in the chain determines the maximum charging current: some chargers only output 42 kilowatts via CCS (Combined Charging System), others up to 300. The vehicles also differ greatly in their input power. The starting point is usually 50 kilowatts.
In general, vehicles can also be charged three-phase at high-voltage outlets. However, you then need a mobile wallbox. Devices such as the go-eCharger or the juice box are supplied with many adapters to be able to tap into any power source on the road.
Loading time
How long does it take to recharge?
The charging time is different for each model because it depends on the capacity of the battery and the maximum current consumption of the vehicle during charging. In theory, the charging time can be easily calculated by dividing the battery capacity by the charging capacity: For example, if the car has a 50-kWh battery and charges at 100 kilowatts, a full charge will take 30 minutes. However, you should only consider calculated times as a guideline, as the maximum charging speed is usually only rarely reached.
If the car is connected to an 11-kilowatt wallbox, charging takes just about five hours. At an earthed socket with 3.6 kilowatts, it takes almost 14 hours for the example vehicle. So if charging has to be fast, you have to use the public infrastructure of fast-charging stations. They deliver 100 to 300 kilowatts at peak times and, depending on the vehicle and its battery size, theoretically allow complete charging in about a quarter of an hour.
Since fast charging stresses the batteries and causes them to age more quickly, the car's electronics limit the charging current as needed: the maximum speed is only reached when the battery is in the optimal temperature window of about 20 degrees Celsius and at a charge level of less than eighty percent.
As a rough rule of thumb, current vehicles with temperature-controlled batteries can charge to 80 percent at a fast charging station in about 15 to 20 minutes; for the remaining twenty percent, you have to calculate about three quarters of an hour, because the charging electronics throttle the charging current close to 100 percent in order to protect the battery.
Mobility during holidays
Can I drive abroad with the e-car without worrying?
Charging points can be found in every direction and most of the payment cards used in Germany work throughout Europe. Travelling on long-distance roads is not a problem because of the thin but even blanket of fast-charging stations in many countries. It is more important to find out about the situation at the holiday destination. If the next DC charging station is 100 kilometres away and there is no charging option at the hotel, you will have to rely on public (and slow, see above) AC chargers. If you want to go on holiday with an e-car, you should already pay attention to the AC charging capability of the car when buying it and pay attention to charging options at the destination when booking.
Connectors
What about the plug chaos during charging?
Fortunately, the charging chaos of earlier days is largely history. With the "Combined Charging Standard" (CCS), the DC charging variant has become established in Europe, which includes the AC part in the form of the Type 2 plug. So you can either charge AC with a Type 2 plug, as with the wallbox at home or a destination charger with a maximum of 22 kilowatts, or with the CCS plug. The competing CHAdeMO standard no longer plays a role in this country. Even the former CHAdeMO advocate Nissan switched from CHAdeMO to CCS for its current Ariya model. There is also no chaos at public fast charging stations thanks to the charging station ordinance: they are equipped with CCS and CHAdeMO for DC charging and Type-2 for AC charging.
What you should pay attention to when buying is the maximum AC charging speed at the Type 2 plug. Many manufacturers charge extra for high-performance converters. In the standard configuration, many cars only charge at 7 kilowatts on AC type 2. If you find an upgrade to 11 or even 22 kilowatts in the surcharge list, you should order the extra, because in the countryside and abroad you will sometimes only find AC charging points - there, a faster converter in the vehicle can make a difference of several hours in the charging time.
Cost comparison
Are the costs lower than for the combustion engine?
The e-car bonus at the time of purchase and the tax exemption are offset by higher acquisition costs overall. The question of "cheaper" driving is primarily decided at the charging station and by the foot on the accelerator or e-pedal. With internal combustion engines, the driving behaviour is proportionally much less important than with an e-car because of the already less efficient technology. In urban areas, combustion engines consume more fuel, even though you are driving at lower speeds.
With the much more efficient electric car, consumption increases noticeably at higher speeds due to air resistance and decreases just as noticeably if you use the accelerator and brake sparingly and do not push the top speed on the motorway. Charged at home and driven sensibly, an electric car is cheaper to run than a combustion engine: For example, if the vehicle consumes 20 kWh/100 km, one pays seven euros for a journey of 100 kilometres at an electricity price of 35 cents per kilowatt hour. For a combustion engine with a consumption of 6 l/100 km, it is more than ten euros at current fuel prices.
Longevity
How long does the battery last?
In the meantime, electric cars have been on the market long enough for the first long-term experiences to be made: It turns out that the problems with models that have been on the road for ten years or more are not usually caused by the battery, but by the usual wear and tear on cars, such as rust or worn-out bushings and bearings in the chassis.
Through more elaborate tempering of the batteries and improvements in cell chemistry as well as hidden reserves, almost all manufacturers are now confident enough to guarantee a battery life of at least eight to ten years.
Similar to batteries in mobile devices, however, reaching this limit does not mean that the vehicle is then a case for disposal. Service life usually means the point in time at which the battery still has a residual capacity of 70 to 80 percent of its original value. How quickly the battery ages is also determined to a large extent by how it is treated: Frequent fast charging, charging at very high or very low temperatures and charging or discharging below 20 or above 80 per cent of capacity stress the battery more and shorten its life.
If you always charge your vehicle slowly at a wallbox and keep it in a window of 30 to 70 percent most of the time, after eight years it will have lost only about 10 percent of its original capacity. However, this does not make much of a difference in everyday life: if you buy a vehicle with a large battery and a range of 400 kilometres today, you will still be able to drive around 360 kilometres after ten years if you take good care of the battery - this loss can be almost completely compensated by economical driving.
Charge at home
Do I need a wallbox?
This depends on three factors: the daily mileage, the battery capacity of the car and the average consumption. Since most people often significantly overestimate their daily mileage, they usually do not need a wallbox.
(Bild: BMW)
If you want to know exactly, you can answer the question mathematically. An example calculation: The car consumes 18 kWh/100 km in summer and 26 kWh/100 km in winter. To ensure that there is always enough power in the battery during the cold season, the maximum consumption is used for the calculation. If the vehicle is driven about 50 kilometres a day, the corresponding charging requirement is 13 kWh per day. If the car has ten hours to recharge overnight, the battery can easily be charged with 2.2 kilowatts up to a maximum of 3.6 kilowatts at a conventional safety socket. Recharging for the day's consumption then takes between three and a half and six hours, depending on the socket, which still offers enough time in reserve if a longer trip has to be compensated for during the night.
Driving characteristics
Do e-cars drive like regular cars?
Yes and no. In an e-car, the driving behaviour from the interaction of accelerator, brake and steering is even more dependent on the software than in combustion vehicles. The electric motor brakes the rolling vehicle and returns energy to the battery as soon as you take your foot off the pedal (recuperation). The engine brake is therefore stronger than with the combustion engine.
However, this can be simulated by software - and many manufacturers do this to make it easier for their customers to switch from a combustion engine to an electric car. Most vehicles therefore have at least one driving mode up their sleeve that is modelled on the behaviour of the combustion engine. If you take your foot off the accelerator while the vehicle is rolling, the electric motor remains under power to simulate the rolling behaviour of the combustion engine. Other driving modes recuperate more strongly; some manufacturers allow the recuperation to be adjusted by rocking the steering wheel. The maximum "electric" driving mode is "one-pedal drive". In this mode, the vehicle comes to a complete stop when the accelerator is released, so that the brake pedal is only needed in emergency situations.
As far as driving dynamics are concerned, the cars feel more solid on the road than comparable combustion engines due to their higher weight and the low centre of gravity of the battery pack. The differences become greater the smaller the vehicle. In terms of driving characteristics, a battery-electric Fiat 500 proved to be significantly more elastic in the test than the model with combustion technology.
Another special aspect is the changed acceleration behaviour. Since most models only need one gear due to the high maximum speed of the motor, they can accelerate out of the gearbox without pauses. This winch effect increases the driving pleasure even in moderately motorised e-cars and makes you no longer miss the combustion technology.
Even when it comes to refuelling, there are often changes in behaviour over the service life of an e-vehicle. While the rhythm of a combustion engine is determined by filling up and driving empty, the regular use of an e-vehicle results in a change in refuelling behaviour with a multitude of possible charging points: 30 minutes free of charge in front of the discount store, 2 hours at your favourite Italian restaurant in the (usually only) free E-parking space in the city centre or a few hours under the PV system at the carport at home. After about a year, an inner map of possible charging points emerges and the vehicle's battery is rarely completely full or completely empty.
Safety
Are electric cars more dangerous?
So far, no reliable statistics can be found to prove this. In terms of vehicle fires, the opposite seems to be the case: according to the German Insurance Association, there are 15,000 cases of fire damage to vehicles of all drive types in Germany every year - most of which are comparatively harmless cable fires.
In the media, however, such everyday fires are hardly reported. A Tesla burning down an underground car park is just more exciting than a burning Corsa with a burst fuel line at the side of the road. The bad reputation of electric cars is therefore probably also due to a certain media distortion.
In serious car accidents, the fire risk is likely to be even higher with petrol cars: Petrol is highly flammable and its volatile vapours explosive. If there is a leak somewhere in the fuel lines due to the force of a crash, the heat present at the brakes or the exhaust system is sometimes sufficient to trigger a deflagration with subsequent fire.
However, this does not mean that rechargeable batteries are generally less dangerous. They usually ignite through internal short circuits. This can happen with a defective charging control or through damage after an accident. To minimise the risk of the latter, the cells are well protected in very sturdy and waterproof housings.
However, if a battery fire does occur, the casing is a hindrance because it hardly allows any extinguishing water to reach the source of the fire. And unlike petrol, batteries are more difficult to quench. At high temperatures, the electrolytes evaporate and form highly flammable gases. The bigger problem, however, is that the metal oxides of the battery cells release oxygen at high temperatures, which then feeds the flames. Classical extinguishing - i.e. removing the oxygen from the fire with water or foam - then has hardly any effect because the battery itself supplies the fire with oxygen. In the past, such extreme fires led to reports in which the fire fighters had to sink the burning car in a water tank.
(spo)
