For Volkswagen e-Golf owners keen on monitoring their vehicle’s battery health, the On-Board Diagnostics II (OBD2) system offers a wealth of data. Discussions within the e-Golf community, particularly around tools like OBD11 and VCDS, have highlighted intriguing data points related to battery degradation. This article delves into how OBD2 data can potentially be used to assess the health of your e-Golf battery, focusing on key metrics and initial findings.
One area of interest lies in deciphering the Wh figures listed within module 19 of OBD2 data. Speculation suggests that figures like SOH_Q (State of Health – Quality) and SOH_P (State of Health – Performance) might be directly linked to battery degradation over time. Initial investigations, based on data extracted using OBD11, have attempted to calculate usable battery capacity and its factory state, offering a glimpse into battery health beyond the standard battery gauge.
Let’s examine some initial data points collected from different e-Golf models using OBD2:
Example 1: 2019 e-Golf (December 2018 Build)
- Mileage: 2,852 miles
- Energy storage unit SOC: 15475 Wh
- HV battery Charge State: 49.0%
- SOH_Q: 97%
- SOH_P: 97%
Alt text: OBD2 data readings for a 2019 Volkswagen e-Golf showing energy storage unit SOC, HV battery charge state, and SOH figures, used for battery health analysis.
Based on this data, calculations were performed to estimate usable battery capacity:
- Calculated usable capacity today: 31581 Wh (15475 Wh / 49% * 100%)
- Calculated usable capacity at factory: 32558 Wh (31581 Wh / 97% * 100%)
These calculations suggest that this 2019 e-Golf might have left the factory with approximately 90% of its battery capacity available for user-accessible charging, as indicated by the battery gauge. The “Energy storage unit SOC” reading appears to reflect the vehicle’s current state of charge in Watt-hours (Wh), a theory supported by observed decreases in this figure correlating with vehicle usage. Furthermore, the “HV battery charge state” percentage aligns with the battery percentage displayed in the Car-Net app, suggesting it represents the user-facing State of Charge (SOC) rather than the absolute cell SOC.
Example 2: 2016 e-Golf (August 2016 Build)
- Mileage: 26,154 miles
- Energy storage unit SOC: 15000 Wh
- HV battery Charge State: 80.0%
- SOH_Q: 87%
- SOH_P: 87%
Alt text: OBD2 data values from a 2016 VW e-Golf, including energy storage unit SOC, HV battery charge state, and SOH percentages, relevant for electric vehicle battery degradation assessment.
For this older e-Golf, the calculations yield:
- Calculated usable capacity today: 18750 Wh (15000 Wh / 80% * 100%)
- Calculated usable capacity at factory: 21551 Wh (18750 Wh / 87% * 100%)
The data from the 2016 e-Golf indicates a more significant level of battery capacity reduction compared to the newer 2019 model, which is expected given the mileage and age difference. This further strengthens the hypothesis that OBD2 data, specifically SOH_Q and SOH_P in conjunction with Energy storage unit SOC, can provide valuable insights into e-Golf battery degradation.
To further validate these initial findings and establish a more robust method for diagnosing e-Golf battery health using OBD2, we encourage other e-Golf owners with OBD11 or VCDS tools to contribute their data. Sharing your figures will help build a larger dataset, potentially leading to a community-driven approach for monitoring and understanding e-Golf battery longevity without solely relying on estimations from the trip computer or dealership diagnostics. By pooling our data, we can collectively unlock a deeper understanding of e-Golf battery performance and develop more accurate methods for assessing its long-term health using readily available OBD2 tools and data.
