*Question G6A01:
What is the minimum allowable discharge voltage for maximum life of a standard 12-volt lead-acid battery?*  

*Correct Answer is  C: 10.5 volts*  

### AI Response: (may contain errors)  

To determine the minimum allowable discharge voltage for maximum life of a standard 12-volt lead-acid battery, we need to understand how lead-acid batteries operate.

1. **Correct Answer Explanation (10.5 volts)**:
   - The correct answer is **10.5 volts**. Discharging a lead-acid battery below this voltage can lead to sulfation, which is the formation of lead sulfate crystals that can damage the battery and reduce its capacity and lifespan. Keeping the discharge voltage above 10.5 volts helps maintain the health of the battery.

2. **Incorrect Choices Explanation**:
   - **6 volts**: This is far too low for a 12-volt lead-acid battery. Discharging to this level can cause irreversible damage and significantly shorten the battery's life.
   - **8.5 volts**: Similar to 6 volts, this is also too low. It can lead to sulfation and other forms of damage, making it unsuitable for maintaining battery health.
   - **12 volts**: While this is the nominal voltage of a fully charged lead-acid battery, it is not a discharge voltage. Discharging to 12 volts means the battery is still at full charge, not a minimum discharge voltage.

3. **Useful Rules of Thumb**:
   - For lead-acid batteries, it is generally recommended to avoid discharging below 50% of their capacity to prolong life. This typically corresponds to a voltage of around 12.0 volts.
   - Always aim to recharge the battery before it reaches 10.5 volts to ensure maximum lifespan and performance.

In summary, maintaining a discharge voltage above 10.5 volts is crucial for the longevity of a standard 12-volt lead-acid battery.