RV Technician Practice Exam Prep: Questions and Study Guide

The specific gravity of a fully charged lead-acid battery is approximately 1.265. This measurement is critical because it indicates the state of charge of the electrolyte solution in the battery. In a lead-acid battery, the specific gravity is a ratio that compares the density of the sulfuric acid electrolyte to that of pure water.

At full charge, a lead-acid battery typically has a specific gravity around this value, suggesting optimal performance and capacity. If the specific gravity is significantly lower, it may indicate that the battery is partially discharged or even defective. Therefore, understanding the specific gravity can help in diagnosing battery health, ensuring that the RV stays powered, and extending the lifespan of the battery. This characteristic is essential knowledge for technicians working with RV electrical systems.