What will you lose if your battery fails?

When a battery fails, it impacts all electronic equipment aboard the aircraft. This includes flight instruments, radios, navigation systems, and any other electronic functions that rely on battery power. In a typical general aviation aircraft, the electrical system is crucial for not only communication and navigation but also for important instruments such as altitude and airspeed indicators. Therefore, if the battery fails, the pilot would lose a wide range of electronic capabilities that are vital for safe flight operations.

The radios and navigation equipment are certainly amongst the affected systems, but the failure would also extend to other electronic equipment that is powered by the battery, making the complete loss of all electronic systems the most comprehensive and accurate answer.