A battery test for an electric car involves determining the SoH of the battery. This stands for “State of Health”: the battery status of an electric car. In the EV sector, however, this is still in its infancy because there are no uniform standards and norms. The lack of standards also means that there is no uniform method for calculating battery status.
At EV Shop, we are committed to pioneering the clear and transparent communication of battery status to our customers. Just as the carpass provides transparency to the buyer, we are also advocating the introduction of a mandatory, universal document that reflects the battery status of the electric car. This status would be determined based on a uniform method of calculation so that every buyer gets a fair and clear picture of battery health.
However, it is a simple calculation in theory….
A battery diagnosis in electric cars based on range can assume the following calculation: the current range (corresponding to the current battery status) divided by the range in new condition. The result is then given as a percentage value. What is important in this calculation method, however, is that the current range and new state range are determined under the same conditions. This is easier said than done. The driver’s driving profile and external factors such as temperature and etc. have a significant influence on the range.
Another solution is measuring during the charging process. Unfortunately, even this is not that simple… Even with this technique, there are external factors, such as charging methods, that exert an influence. Moreover, the amount of energy used in charging will always exceed the amount of energy available while driving.
EV Shop’s solution: a brand-independent battery test for electric vehicles
To still provide our customers with a fair and meaningful result, our battery status calculation is based on the recoverable energy in kWh. We hereby use a device that CARA/TUV-gecertificeerd is. The extractable energy in kWh is comparable to the tank capacity in liters of gasoline or diesel that can be extracted from a combustion vehicle.
As mentioned earlier, there are many external factors to consider. In addition, stored energy is not 100% available.
Therefore, EVShop uses numerous correction factors when calculating the result. For example, EV Shop, with its battery diagnostic equipment, calculates each evaluation based on a battery temperature and a driving profile similar to WLTP.
With our advanced test, we measure the SoH (State of Health, or battery status) of your vehicle while driving, from a full charge (100%) until the battery has only 5% capacity left.
In addition, EV Shop also features a quick test. This test takes only 3 minutes. This test can be performed on a large number of electric vehicles, of different brands.
The quick test provides a comprehensive analysis of high-voltage battery functionality without a test drive. This is quite simple and quick, for example for testing when taking delivery of a used leased car.
“At EV Shop, we insist on being pioneers in transparently informing buyers about the battery status of their vehicle. We therefore advocate that a battery status document like the carpass should be required to honestly inform buyers about the status of the electric vehicle.”
– Heireman GINO, Founder EV Shop BV
Just the deep theory…
The advanced analysis is based on all data collected during the discharge of the battery. Particularly many parameters of the vehicle are transferred in real time to a data platform. Once the discharge is complete, the transmitted data is validated and the battery status (SoH) is analyzed on this basis.
These are then converted to a result to be compared using the required compensation factors. The calculation is based on the SoC display in the vehicle for the total 100% and is transparently displayed in kWh on the battery certificate. The result is the value used to assess the condition of a battery.
With the calculation of the energy content in current state (measured usable energy of the test vehicle /100% to 0% according to the display/) divided by the energy in new state (measured usable energy of the tested vehicle model in new state /100% to 0% according to the display/), we obtain a percentage value that gives information about the battery status (SoH).
To learn more about the importance of this test?
Read also: CARA delivers on battery health check
Example of a battery test on a used electric vehicle
The measured battery capacity (100% to 0% according to the display) for a car model is 60 kWh. This is the value for the energy content in new condition.
In the advanced test only 54 kWh can still be included, this is the value for the energy content now.
54 kWh/60 kWh = 0.9 * 100 = 90%
This means that the SoH of this battery is still 90% compared to the new state.
- The quick test is 69 euros excluding VAT at our office.
We also provide our battery diagnostics to companies with fleets and leasing firms. Contact us to provide these services.
