Ampere-Hour

BATTERY TERMINOLOGY Batteries Since the electrolyte of a lead-acid battery consists of a mixture of water and sulfuric acid, the specific gravity of the electrolyte will fall between 1.000 and 1.835. Normally, the electrolyte for a battery is mixed such that the specific gravity is less than 1.350. Specific gravity is measured with a Figure 1 Simple Hydrometer hydrometer. A simple hydrometer consists of a glass float inside a glass tube, as shown in Figure 1. The hydrometer float is weighted at one end and sealed at both ends. A scale calibrated in specific gravity is positioned lengthwise along the body of the float. The float is placed inside the glass tube, and the fluid to be tested is drawn into the tube. As the fluid is drawn into the tube, the hydrometer float will sink to a certain level in the fluid. The extent to which the hydrometer float protrudes above the level of the fluid depends on the specific gravity of the fluid. The reading on the float scale at the surface of the fluid is the specific gravity of the fluid. Ampere-Hour An ampere-hour is defined as a current of one ampere flowing for one hour. If you multiply the current in amperes by the time of flow in hours, the result is the total number of ampere-hours. Ampere- hours are normally used to indicate the amount of energy a storage battery can deliver. ES-04 Page 2 Rev. 0