Adjusting the Electrolyte
If the specific gravity of the electrolyte is 1.280 to 1.300 at the end of the charge, the battery is ready for testing. If the specific gravity is below or above these figures, draw off as much electrolyte as you can with the hydrometer. If the specific gravity is below 1.280, add enough 1.400 specific gravity electrolyte with the hydrometer to bring the level up to the correct height (about 1/2 inch above tops of plates). If the specific gravity is above 1.300, add a-similar amount of distilled water instead of electrolyte. If the specific gravity is not more than 15 points (.015) too low or too high, adjust as directed above. If the variation is greater than this, pour out all the electrolyte and add fresh 1.280 specific gravity electrolyte.
After adjusting the electrolyte, continue the charge until the gravity of all cells is 1.280-1.300, and there is no further change in gravity for at least two hours. Then take the battery off charge and make a final measurement of the specific gravity. Measure the temperature at the same time, and if it varies more than 10° above or below 70°, correct the hydrometer readings by adding one point (.001 sp. gr.) for each 3 degrees above 70°, and subtracting one point (.001 sp. gr.) for each 3 degrees below 70°. Be sure to wipe off any electrolyte which you spilled on the battery in adjusting the electrolyte or measuring the specific gravity. Use a rag dipped in ammonia, or baking soda solution.