For PHEV battery health checks, a combination of owner monitoring, professional evaluations, and manufacturer recommendations should guide the frequency:
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Built-in battery management system (BMS) checks
Monitor your vehicle’s BMS regularly via the dashboard or manufacturer app for State of Health (SoH) metrics. Many systems display range estimates and charging efficiency, which indirectly reflect battery health. Check this monthly or whenever noticeable range drops occur. -
Professional diagnostic testing
Mitsubishi-specific protocols (as an example from the results) suggest full EV battery health checks require dealer diagnostics involving overnight analysis, while 12V battery tests may take less time. For PHEVs, schedule professional tests:- Annually as a preventive measure, especially for older models
- Before purchasing/selling the vehicle
- If range declines significantly (e.g., >10% below expected capacity)
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Manufacturer guidance
Most warranties cover batteries for 8-10 years or until 70-80% capacity remains. Adhere to your PHEV’s service manual intervals, which often align with major maintenance schedules (e.g., every 15,000–30,000 miles). -
Behavior-based monitoring
Track charging habits and performance:- Avoid frequent deep discharges (keep charge between 20%-80% when possible)
- Limit DC fast charging unless necessary
- Note charging speed changes or unusual power fluctuations.
Geotab’s analysis of 10,000 EVs shows ~1.8% annual degradation under moderate use, which can serve as a benchmark for PHEV owners to contextualize their battery’s performance.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-often-should-i-check-the-battery-health-in-a-phev/
