ARRL Technician Practice Exam 2025 – Complete Prep Guide

A conventional 12-volt storage battery, commonly used in various applications including automobiles and amateur radio equipment, presents a significant hazard due to the potential accumulation of explosive gases, particularly hydrogen. When a battery is charged, especially if overcharged, it can release hydrogen gas, which is highly flammable and can lead to explosions if ignited. Proper ventilation is essential to mitigate this risk, ensuring that any gases can dissipate safely into the environment.

Corroding metal surfaces, while a concern, is not as urgent as the explosive gas hazard associated with improper battery venting. The claim that there is no significant hazard downplays the serious risks associated with handling and charging batteries, and the notion that batteries can only be safely charged during the day is not accurate; safety measures regarding ventilation and handling apply regardless of the time of day. Therefore, the correct choice highlights the critical need for appropriate battery maintenance and management to avoid the risks posed by explosive gases.