How much electricity an electric car actually consumes cannot be determined simply by looking at the screens in the cockpit.
Because the value shown there corresponds - so we hope - to the electricity consumed during the journey.
This not only flows into the drive, but also into the air conditioning of the cabin and the battery.
John Winterhagen
Editor in the economy, technology and engine department
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Anyone who fills up at a public charging station or can track the electricity drawn from the wall box at home via energy monitoring will get a realistic picture, but only if you really charge the battery at least twice in a row and note the mileage.
There will be a discrepancy along the way.
The electricity supplied and to be paid for is about ten percent higher than that consumed on board.
It can also be twice as much when charging at very high power.
Calculate conversion losses
The causes include unavoidable losses that occur when current flows through an electrical conductor.
Basically, the following applies: the longer the cable, calculated from the meter, the higher the loss percentage.
If it is a device that works with alternating current, i.e. every wall box, conversion losses from the rectifier must also be taken into account.
The car's own consumption during charging should not be underestimated.
Numerous control units are active for monitoring, and a ten-hour stand-by operation can add up to three kilowatt hours.
This also applies during fast charging, but it doesn't last as long either.
To do this, the battery must be kept at a comfortable temperature.
The charging losses are included in the manufacturer's consumption data.
According to the standard, the current before the charger is measured.