Volvo PHEV don’t make it easy to check battery health, leaving owners to figure it out on their own. One way to test the battery is by draining it fully and then charging it to 100%. After testing the battery, it’s clear that Volvo has designed a system that preserves battery health, even without a manual charge limit feature.
How the Battery Performs
Volvo PHEVs don’t offer a simple way to limit charging to around 80%, which is common in EVs to help protect the battery. Instead, the system keeps part of the battery’s capacity in reserve, which helps reduce degradation over time. By using an OBD diagnostics tool and a smartphone app, I monitored the car’s battery management system (BMS). The BMS data is more accurate than the instrument cluster’s battery gauge.
Volvo claims that the gross battery capacity is 18.8 kWh, with a usable capacity of 14.9 kWh. But the actual performance tells a different story. When I drained the battery, the BMS showed that the battery still had charge left, even when the instrument cluster showed zero miles.
Battery Charging Results
After charging the battery to 100%, the BMS reported a 94% state of charge, with a voltage of 418V. This shows that Volvo’s system reserves some of the capacity, helping protect the battery from degradation. The vehicle does not require a manual charge limit feature because the system automatically creates this buffer.
Degradation Findings
After charging the battery, I checked the energy used to fill it. My home charger delivered 16.77 kWh, and after accounting for energy losses, I found that 15 kWh entered the battery. Volvo’s official figure of 14.9 kWh for usable energy holds up. This means the battery hasn’t degraded much after almost four years and 42,000 miles, which is great news for anyone concerned about long-term battery performance.
Electric Range
The electric range remains strong, even with nearly 42,000 miles on the car. In winter, the car averages around 37 miles (60 km) on a full charge. In summer, the range improves to around 55 miles (90 km). At one point, the car reached 68 miles (110 km) on a full charge, but that hasn’t happened again. This range is in line with what Volvo claims for its PHEVs.
Looking Ahead
Although the battery has held up well so far, it’s important to note that battery health typically declines over time. Research from Germany’s ADAC indicates that Volvo PHEVs retain around 85% of their original capacity after 125,000 miles (200,000 kilometers). So, I expect the battery to degrade slowly, but it should still perform well for many more miles.
Mercedes-Benz plug-in hybrids experience less battery degradation, while Mitsubishi’s PHEVs tend to see more.
The Volvo PHEV is a reliable option for those looking for a plug-in hybrid that offers good electric range, strong performance, and long battery life. The battery health remains strong after 42,000 miles, thanks to Volvo’s well-designed battery management system.
