The nominal open-circuit voltage of one cell of a fully charged lead-acid battery is approximately how many volts?

Correct Answer: Option A — 2 volts

A fully charged lead-acid battery cell has a nominal open-circuit voltage of approximately 2.0 volts, governed by the electrochemical reaction between lead peroxide, spongy lead, and sulfuric acid. 46 CFR Subchapter J and IEEE 45 reference this standard cell voltage for calculating total bank voltages and charging parameters.