The PKC Power checK Control certificate provides key information about the battery health of an electric vehicle. Understanding its metrics is crucial for evaluating the State of Health (SOH) and identifying potential issues. Below is a guide to interpreting the main data points:
1. State-of-Health (SOH)
- This percentage represents the remaining capacity of the battery compared to its original factory condition.
- 100% SOH means the battery is performing as it did when new.
- A lower SOH indicates degradation, affecting range and performance.
- Typical thresholds:
- Above 90%: Excellent condition
- 70-90%: Good condition, minor degradation
- Below 70%: Noticeable degradation, reduced range
- Below 50%: Significant degradation, potential impact on resale value
2. Cell Imbalance
- Indicates the voltage difference between the highest and lowest battery cells (measured in millivolts, mV).
- A high imbalance (above 50 mV) suggests issues such as:
- Module Replacement: If an entire section of cells shows higher voltages, some battery modules may have been replaced.
- Faulty Cells: If one or more cells show significantly lower voltage, they may be deteriorating, affecting reliability.
3. Energy Consumption (Wh/km)
- Measures the total energy used by the battery for:
- Driving
- Climate control (A/C, heating)
- Auxiliary systems (lights, infotainment)
- A higher Wh/km value suggests higher stress and usage on the battery.
- Efficiency benchmarks:
- Below 180 Wh/km: Very efficient
- 180-220 Wh/km: Typical range
- Above 220 Wh/km: High energy consumption, possible battery stress
4. Charging History
Fast Charging Count
- This tracks the number of DC fast charging sessions the vehicle has undergone.
- Frequent fast charging accelerates battery wear due to higher heat generation.
- Guidelines:
- Less than 30% of total charges → Ideal
- 30-60% → Acceptable but moderate impact
- Above 60% → Possible faster battery degradation
Slow Charging Count
- Tracks the number of AC slow charging sessions (e.g., home charging).
- Slow charging is better for battery longevity. A higher number here is a positive indicator.
5. Battery Usage and Lifetime Cycles
- Some PKC certificates may show total energy throughput (kWh) and charge cycles.
- Lower cycles mean the battery has been used less.
- Higher cycles (>1,000) suggest significant use, but longevity also depends on charging habits.
Key Takeaways for Reading a PKC Certificate
✅ SOH above 80% → Good battery health
✅ Cell imbalance below 50 mV → No major issues
✅ High slow charge count, low fast charge count → Well-maintained battery
⚠️ SOH below 50% or high cell imbalance → Possible battery concerns
By analyzing these data points, you can accurately assess the battery’s condition and predict its remaining lifespan, making informed decisions when buying or selling an electric vehicle.