Determining the State of Health (SOH) of your Kia electric vehicle’s battery is crucial for understanding its performance and longevity. While dealerships can provide SOH readings, it’s important to be informed about potential inaccuracies and how you can use car scanner apps to gain a clearer picture of your battery’s condition. Some Kia dealers might inadvertently provide misleading SOH figures, which can be frustrating when you’re trying to assess your EV’s battery health.
One common issue reported by Kia EV owners is that dealerships sometimes dismiss SOH values that aren’t obtained using the official KIA Diagnostic Unit (KDU). Furthermore, some dealers might believe that applying Battery Management System (BMS) updates will improve the SOH reading. In reality, applying these updates before properly assessing the battery can actually lead to inaccurate readings. This is because BMS updates can reset the system to default values, requiring several charge cycles before valid battery data becomes available again. When this happens, dealers might see a temporarily inflated SOH value, often well over 70%, and conclude that the battery is healthy, sending you on your way without addressing potential underlying issues.
To ensure you get an accurate assessment of your Kia EV battery’s SOH at the dealership, it’s advisable to be proactive. A key piece of documentation to be aware of is PS 548. It’s recommended to bring a copy of PS 548 with you when visiting the dealer and specifically request that they follow the procedure outlined in this document precisely. Clearly communicate that you understand that performing BMS updates before reading the battery data will prevent an accurate SOH reading. Highlight the relevant sections of PS 548 that emphasize reading the BMS data before any updates are applied. Drawing attention to these crucial instructions can help ensure the dealer conducts the test correctly.
If, after following the PS 548 procedure correctly, the dealership obtains an SOH reading of less than 70%, this should trigger a report to KIA Corporate. According to reports, an SOH reading below this threshold should typically result in a battery replacement under warranty.
Beyond relying solely on dealership readings, you can also independently estimate your battery’s SOH using a simple calculation method. This can be particularly useful as a preliminary check or to compare against dealership findings. Here’s how to calculate your SOH:
- Charge and Reset: Fully charge your Kia EV. After charging is complete, reset your car’s m/kWh meter. This meter will usually display “–” initially after being reset.
- Initial Readings: Note down your current mileage and the battery percentage (if it’s not already at 100% after charging).
- Discharge and Record: Drive your vehicle until you need to charge again. Before commencing the next charge, note down your new mileage, the battery percentage remaining, and the m/kWh reading displayed on your meter.
- Calculate kWh Consumed: Subtract the initial mileage from the final mileage to get the miles driven. Divide this mileage difference by the m/kWh reading. This result approximates the kilowatt-hours (kWh) of energy consumed from the battery.
- Calculate Percentage Difference: Determine the difference in battery percentages from the start to the end of your test. Convert this percentage difference into a decimal fraction by dividing by 100 (or multiplying by 0.01).
- Calculate Full Capacity: Divide the kWh consumed (from step 4) by the decimal fraction representing the percentage difference (from step 5). This calculation estimates the current usable kWh capacity of your battery at a 100% charge.
- Determine SOH: Divide the calculated full capacity (from step 6) by the nominal battery size of your Kia EV model. The nominal battery size varies depending on your specific model (e.g., 27 kWh, 30 kWh, 39.2 kWh, 64 kWh, etc.). Multiply this result by 100 to express the SOH as a percentage.
This DIY calculation method has been tested against more sophisticated tools like Spy (presumably a battery diagnostic tool) and has shown to provide reasonably close results, making it a valuable tool for Kia EV owners to monitor their battery health.
Understanding your Kia EV’s battery SOH is essential for maintaining your vehicle’s performance and ensuring you’re getting the range you expect. By being informed about potential dealership procedures and utilizing tools like car scanner apps (or even manual calculations), you can proactively manage your EV’s battery health and address any concerns effectively.
