EV battery declared failed immediately after warranty expiry – need legal advice
My spouse and I work in the fields of Material Science and Electrical Engineering, so we're trying to look at this from both an engineering and consumer-rights perspective.
We own an EV from a reputed manufacturer. The battery warranty expired on 31/03/2026. The vehicle has covered only ~19.7 k kms and, based on usage, has likely undergone only a few hundred charge cycles(at the most 220-250). We generally followed recommended battery practices and observed no noticeable range degradation before the issue appeared.
Around mid-April 2026, the vehicle started showing abnormal SoC behaviour (battery percentage jumping between values) along with warning indications. The authorised service centre performed a software/firmware update and the vehicle immediately returned to normal operation.
About a month later, the same issue reappeared. This time, instead of a software remedy, a complete battery replacement (around ₹35,000) was recommended.
The manufacturer has refused to provide diagnostic reports, SoH data, cycle count, fault logs, cell voltage data, or even the "Battery Failure Certificate" that was verbally promised. Their position is essentially: battery replacement is chargeable because the warranty has expired.
From an engineering perspective, the situation looks odd. If the issue was purely due to irreversible battery degradation, how did a software intervention apparently restore normal operation in April? One possibility is that the update altered how the BMS interpreted or handled cell-level deviations. Another is that there was an underlying issue that temporarily became less visible. Or it could be something entirely different. Without the diagnostic data, it's impossible to know.
What makes us uncomfortable is that a major replacement recommendation has been made while the underlying technical basis is being withheld.
Current status: the manufacturer states that the diagnostic data is available with the authorised service centre and not with them, while the service centre's position is simply that the battery is out of warranty and the matter is closed. Over the last month, I have sent multiple detailed emails seeking diagnostic records and technical clarification, but apart from a generic one-line response stating that the battery is out of warranty, none of the technical questions have been answered.
For those with EV, battery, consumer law, or litigation experience:
- What would be your next step?
- Does the timing (issue appearing immediately after warranty expiry - around 10 days) matter legally?
- Would you proceed through NCH, Consumer forum or some other route?
- Does this sound more like normal degradation, a latent defect, a BMS/software issue, or something else?
Looking for informed opinions, especially from people who have handled similar disputes.