Recuperation 3
Sometimes there are stories in the press or social media that report incredible savings through recuperation. Manufacturers of electric cars also use some of this to artificially increase their range. Hardly any of it is in step
with actual practice.
One could use the significantly lower consumption compared to the combustion engine in the city as evidence. But this is usually based on other factors, e.g. the fact that the automatic start-stop system always works in an
electric car or that a combustion engine does not have to be laboriously brought up to speed when restarting, in order to then pull the whole vehicle along with it.
The average speeds in the city are naturally lower, which is more suitable for electric cars. Yes, some recuperation can also be involved, but you just have to be sure that more energy can never come out than was previously
put into it. It's usually far less than half.
Of course, you shouldn't brake hard and an estimate depends heavily on the habits of the driver. There are (few) people who drive very carefully and take advantage of every gap. They may recuperate a lot, but they also use
more. However, the majority of people react rather slowly in city traffic, which perhaps even benefits the overall balance.
Traffic light switching also plays a major role. The fact is, however, that given the speeds in the city, there is only limited scope for recuperation overall. So let's go onto the motorway, bypassing the country roads, where most
of the electricity is probably used. What is the situation with recuperation here?
You can easily check this yourself by observing how often you brake slightly to moderately hard or take your foot off the accelerator. Only in these situations can recuperation take place. So not when driving steadily, no matter
what speed. Add this up for an average journey of 200 km between two charging stations as an assumption.
Of course, this also depends on the mentality of the driver. But for well-known reasons, an electric car is handled even more calmly than a car with combustion engine. To put it bluntly, you could perhaps recuperate 5 percent
of the time on a busy highway. As a model, we assume a speed loss from 130 to 100 km/h, i.e. from 25 to 15 kW in relation to the engine power for a reasonably aerodynamic car.
The 5 percent quickly becomes 4 percent because the system also has to switch over and the recuperation is made up of many small parts. The 10 kW difference doesn't really reach the battery either, because the
production of electrical energy from kinetic energy is accompanied by extremely poor efficiency. The electric drive motor is designed, if at all, for low consumption and not for cheap energy recovery.
Let's be generous and say a third would come back, which would mean a good 3 kW. And what time do we have to use as a basis? If you aim for 130 km/h, you can usually achieve an average speed of around 100 km/h on
German motorways, i.e. 2 hours of driving time between two charges. At 4 percent, that's 5 minutes, in which a good 3 kW goes back into the battery.
Now you can dispute the stated assumptions all you want, but there is no getting around the fact that less than 0.2 kWh was saved in this example. Motorways are anything but suitable for recuperation. If you're very lucky,
you'll find a downhill section somewhere in the south where you can maintain a speed of 130 km/h by 'sailing', but there is often still a speed limit.
Saving money isn't that easy and it wouldn't be the first time that potential consumers were given nonsense before purchasing that later turned out to be soap bubbles. That's also the problem with hybrid drives, which have
increased consumption on motorway hills due to more weight, which they usually can't make up for when going down hills. Then the combustion engine has to charge the battery for the next trip through the city.
The plug-in hybrids benefit almost exclusively from their first charge because they are not recharged on the go. Which brings us back to city traffic. If they are operated primarily there and only electrically, they benefit from all
the advantages described above, including recuperation. Climate-friendly if it is the only car and is only used for vacation once or twice a year.
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