The German Automobile Club ADAC investigated how much amperage was lost before it moved from the switchgear to the electric car’s traction battery. The resulting figures showed that the percentage is up to tens of percent. However, it depends not only on the brand and type of electric vehicle, but also on the way you recharge the energy at home.
“How much does that cost you?” A question that owners of internal combustion cars can answer quite accurately, because gas station counters and on-board computers can measure consumption up to a tenth of a liter.
However, the situation is more complicated for electric cars, because not all the kilowatt-hours that pass through the electricity meter in the circuit breakers of the house ends up in the traction battery. Although the on-board computer can show the consumption quite accurately, in reality the user will pay more for energy than he thinks.
Automobile club measurements have shown that losses are unavoidable when fully recharging an electric vehicle. However, it can be mitigated by using a suitable charging method. Unfortunately, the test confirmed that the least effective way to charge an electric car is also the most convenient, which does not require any additional investment: plugging the car into a 230V household socket.
According to the results of ADAC, charging from a home wall shows much lower losses. It is a device that must be purchased and installed by a specialized company. If connecting the charging box to the home network does not require additional modifications to the building, then it will cost approximately 20,000 kroner. However, in many cases, it is necessary to extend a new cable from the switchboard – the power of the wallbox reaches 11 kW, and the wiring of the old house is usually not enough for this.
However, it is interesting to note that the wallbox shows the least power loss during charging when operating at full capacity. Its electronics are able to regulate the current consumption so that there is no overload on the household circuit breakers. Usually in the case of connecting several high-consuming appliances in the house.
Testing showed that lower recharging from the charging box increased power losses in all cars tested, even double that in the case of the Fiat 500e. In addition to a representative from Italy, Renault Zoe, Volkswagen iD3 and Tesla Model 3 also took part in the tests.
Alternating current (AC) charge losses
|Model||230 volt electrical socket||Wallbox Unlimited Energy/Loss||Wallbox Energy/Loss reduced|
|Renault Zoe||2.3 kW / 24.2%||11 kW / 9.7%||unmeasured|
|Volkswagen ID.3||2.3 kW / 13.6%||11 kW / 9.0%||5.5 kW / 9.2%|
|Tesla Model 3||2.3 kW / 15.2%||11 kW / 7.7%||3.5 kW / 11.4%|
|Fiat 500 E||2.3 kW / 12.7%||11 kW / 6.3%||3.6 kW / 13.9%|
When charging at home, one of the biggest sources of energy waste is converting AC to DC. While the first can be found in the household distribution network, the traction battery for an electric car works with the second, where energy is stored. This loss, which according to measurements by the Automobile Club is 5 to 10 percent depending on the type of vehicle, can only be avoided if the vehicle is charged with DC fast chargers. Direct current “flows” from them to the car. AC/DC conversion, which would otherwise occur in the vehicle’s built-in voltage converter, is omitted in this case.
However, according to the results of ADAC, the 12V network of the electric car also consumes an astonishing amount. Several controllers are also active during the charging process, consuming between 100 and 300 watts in total. Other losses also occur in home electrical distribution systems, where standards in this case are four percent.
Some electric car owners also use extension cables to charge from a home socket. The thinner it is, the more energy is lost from it. From a layman’s perspective, this can be recognized by the fact that it heats up during charging. However, we do not learn anything about it in the Auto Club test, because the car manufacturer does not recommend its use for safety reasons.
However, in addition to the relatively large energy losses, home charging also brings some advantages. ADAC mentions the fact that there is no need to cool the battery during slow charging. This is also related to the fact that lower charging power is more gentle on the battery than replenishing power with a fast charger.
However, the effect of slow charging only appears after some time in the form of less battery capacity loss. However, it is difficult to ascertain the exact numbers. This is because batteries come from different manufacturers and everyone reacts to fast charging differently. It also depends on the effectiveness of managing the temperature of a particular vehicle, or whether it was originally equipped.
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