12V Battery vs. High Voltage Battery: Which one is failing?
Don't spend thousands on a hybrid pack if you only need a $200 12V battery. Learn the difference between these two systems.
7 min read
The 'hidden' battery
Every hybrid has two batteries: the large high-voltage (HV) pack that moves the car, and a standard 12V auxiliary battery that powers the electronics. If the 12V battery is weak, it can throw 'ghost' codes that look like a failing HV pack.
Symptoms of a failing 12V battery
If your dash lights flicker, the car takes multiple tries to start, or you see random error codes that disappear and reappear, your 12V battery is likely the culprit. This is extremely common in Phoenix, where heat kills 12V batteries every 2 years.
Testing and replacement
Always test your 12V battery before replacing the high-voltage pack. A simple load test can save you thousands of dollars and hours of frustration.