1. When May a Battery Be Left on the Car?
(a) When you find that the specific gravity of all cells is more than 1.150, the voltage of each cell is at least 2, the voltage doe's not drop when the lights are turned on, or the lights do not become very dim when the engine is cranked with the starting motor, there are no loose terminals or connectors, the sealing compound is not broken or cracked so as to cause a "slopper," the electrolyte covers the plates, the box is not rotted by acid, and there are no broken jars.
These conditions will exist only if battery has been well taken care of, and some trouble has suddenly and recently arisen, such as caused by a break in one of the battery cables, loosening of a cable connection at the battery or in the line to the starting motor.
2. When Should a Battery Be Removed From Car?
(a) When you find broken sealing compound, causing the battery to be a "slopper."
(b) When you find inter-cell connectors and terminals loose, corroded, or poorly burned on.
(c) When you find box badly rotted by acid, or otherwise defective.
(d) When you find a cracked jar, indicated by lower part of case being acid soaked, or by low electrolyte, or find that electrolyte level falls below the tops of the plates soon after adding water.
(e) When you find a dead cell, indicated by very low or no voltage, even on open circuit.
(f) When specific gravity of electrolyte is less than 1.150, or gravity readings of cells vary considerably.