4-30. STORAGE BATTERIES AND BATTERY BOX (cont)
Check the specific gravity as follows:
Place the hydrometer in a cell and remove enough electrolyte to fill the barrel of the syringe to a level which will
permit the hydrometer to float freely without touching the barrel at either top or bottom. Allow the rubber bulb to
expand completely and hold syringe by the neck of the bulb.
Shake the syringe gently to be sure hydrometer is floating freely.
Hold the syringe at eye level.
Record the indication at the point at which the electrolyte level appears to intersect the stem of the hydrometer.
The fully charged specific gravity varies in different types of batteries and is shown on the battery
nameplate. Readings should register in the vicinity of 1280 points.
The discharged specific gravity (not shown on the battery nameplate) also varies with battery type but is
usually around 130 to 140 points lower than the fully charged specific gravity.
A specific gravity reading 100 points below the full charge valve is a warning of either battery or charging
problems. A specific gravity reading between cells of the same battery that differs more than 20 points
may indicate a dead cell.
Add distilled water to 1/8 inch (3.2 mm) below the bottom of the filling tube in the cover.
Check the tightness of the connector bolts and apply a thin coating of petrolatum. Wipe off excess with a clean
Lower door (1) and remove nuts (2), bolts (3), and cables (4) and (5) from all batteries.
Remove two nuts (6) and lockwashers (7) and remove bracket (8).
Slide batteries (9) from battery box. Note the location of the wooden blocking (10).