Are you curious about the real health of your 2019 Volkswagen e-Golf’s battery? While the dashboard gives you a charge percentage, accessing deeper data can reveal more about its long-term condition. Thanks to OBD2 (On-Board Diagnostics II) and tools like OBD11 or VCDS, e-Golf owners can now delve into battery health metrics that were once only accessible to technicians.
This article explores how to use OBD2 data from a 2019 e-Golf to understand battery degradation. We’ll break down key data points and calculations shared by an e-Golf owner, providing a starting point for you to assess your own vehicle’s battery health.
One e-Golf enthusiast investigated module 19 using OBD11 and shared some intriguing findings related to battery State of Health (SOH). The speculation is that “SOH_Q” and “SOH_P” figures within the OBD2 data are indicators of battery degradation. Let’s examine the data and calculations to understand this further.
Analyzing Real-World OBD2 Data from a 2019 e-Golf
Here’s the OBD2 data shared from a 2019 e-Golf (built in December 2018) with only 2,852 miles:
- Energy storage unit SOC: 15475 Wh
- HV battery Charge State: 49.0 %
- SOH_Q: 97%
- SOH_P: 97%
The “Energy storage unit SOC” (State of Charge) appears to represent the current charge level in Watt-hours (Wh). The user observed this figure decreasing in 100Wh increments while the car was running, reinforcing this interpretation. Notably, the “HV battery Charge State” matches the percentage displayed in the Car-Net app, indicating this is the user-facing SOC, not the absolute cell SOC.
Calculating Usable Battery Capacity and Degradation
Based on this data, the e-Golf owner performed some calculations to estimate the usable battery capacity:
For Today’s Usable Capacity:
(Energy storage unit SOC / HV battery Charge State) * 100
(15475 Wh / 49) * 100 = 31581 Wh
This calculation suggests that at the time of measurement, the usable battery capacity was approximately 31,581 Wh.
Estimating Factory Usable Capacity:
To estimate the original usable capacity when the car was new, the user factored in the SOH figures:
(Current Usable Capacity / SOH_Q) * 100
(31581 Wh / 97) * 100 = 32558 Wh
This calculation estimates the factory usable capacity to be around 32,558 Wh. Comparing this to the current usable capacity (31,581 Wh) suggests a minor level of battery degradation in this low-mileage 2019 e-Golf.
Comparison with a 2016 e-Golf
To further validate these findings, the owner also shared data from a 2016 e-Golf with significantly higher mileage (26,154 miles):
- Energy storage unit SOC: 15000 Wh
- HV battery Charge State: 80.0 %
- SOH_Q: 87%
- SOH_P: 87%
Calculations for the 2016 e-Golf:
Calculated usable capacity today:
(15000 Wh / 80) * 100 = 18750 Wh
Calculated usable capacity at factory:
(18750 Wh / 87) * 100 = 21551 Wh
The 2016 e-Golf data shows a more significant drop in usable capacity compared to its estimated factory capacity, which is expected given the higher mileage and age.
Call to Action: Share Your OBD2 Data!
This initial data analysis is promising, suggesting that OBD2 readings, particularly SOH_Q and SOH_P, combined with these calculations, could offer a way to monitor e-Golf battery health over time.
To strengthen this understanding and develop a more robust method for diagnosing battery health, we need more data! If you own a 2019 e-Golf or another model year and have access to OBD11 or VCDS, please contribute your data.
Specifically, we are interested in the following figures from Module 19:
- Energy storage unit SOC
- HV battery Charge State
- SOH_Q
- SOH_P
- Vehicle Mileage and Model Year
By pooling data from more e-Golf owners, we can refine these calculations, establish baseline battery health ranges, and potentially create a community-driven resource for e-Golf battery diagnostics. Your contribution can help unlock valuable insights into EV battery longevity and empower e-Golf owners with better information about their vehicle’s condition.
