An unusual problem arose with a 2023 Mercedes-Benz GLC plug-in hybrid at the Kokkolan Autohuolto service shop, which had been sitting in a dealership for an extended time. The vehicle, which had traveled approximately 40,000 kilometers, suffered from a defective high-voltage battery, incurring costs of thousands of euros. Entrepreneur Jesse Haapala explains that the situation was abnormal, noting that the car had been moved around the dealership, but eventually had remained stationary for too long, resulting in the 12-volt battery becoming completely depleted.

As a consequence of the 12-volt battery's failure, the high-voltage battery began to continuously charge the 12-volt system, a process that should have ceased once the voltage dropped to dangerously low levels. Typically, the battery management system (BMS) is designed to prevent overcharging and protect the battery cells from going below a certain threshold. However, in this instance, it failed to intervene, and the high-voltage battery continued charging even when the individual cell voltage dropped to under two volts, leading to irreversible damage to the battery cells.

This incident highlights essential issues surrounding the maintenance and management of electric vehicle batteries, especially in models like the GLC hybrid. It raises concerns over the safety systems in place that are supposed to prevent battery failure, as well as the economic implications for dealerships in cases where vehicles remain unsold for long periods. Such problems not only affect dealership profitability but also raise broader questions about electric vehicle reliability and care in long-term storage situations.