With a fully charged battery the specific gravity of the solution will be from 1.280 to 1.300.
Specific gravity readings above 1.200 indicates that the battery is more than half charged.
Specific gravity readings below 1.200, but above 1.150 indicates battery less than half charged.
Gravity below 1.150 indicates battery discharged or run down.
Should the gravity fall below 1.150 the gas motor should be given a long run with all lights turned off, to restore the battery.
This condition may result from leaving a car standing for prolonged periods with all lights in use and insufficient running of the gas motor in between these periods to replace the current taken to supply the lights.
When the specific gravity shows the battery to be half discharged, the lights should be used sparingly until the gravity rises to approximately 1.275.
If the specific gravity in one cell is much lower than that of the others, and if successive readings show the difference to be increasing, this indicates that the cell is not in good order.
If one cell regularly requires more water than the others (continually lowering the specific gravity), a leaky jar is indicated. Leaky jars should be replaced immediately.
If there is no leak and the specific gravity falls 50 to 75 points below that of the other cells in the battery, an internal short circuit is indicated and should be remedied.