Crown C48-2+2 Owner's Manual And Service Manual page 38

OPERATION AND SERVICE INFORMATION
Fig.22 Hydrometer
Specific gravity is the measurement of a liquid that is compared to a baseline. The baseline is water which is
assigned a base number of 1.000. The concentration of sulfuric acid to water in a new golf car battery is 1.280
which means that the electrolyte weighs 1.280 times the weight of the same volume of water. A fully charged
battery will test at 1.275 -1.280 while a discharged battery will read in the 1.140 range.
NOTE
Do not perform a hydrometer test on a battery that has just been watered.The battery must go
through at least one charge and discharge cycle in order to permit the water to adequately mix with the
electrolyte.
The temperature of the electrolyte is important since the hydrometer reading must be corrected to 80° F (27°
C). High quality hydrometers are equipped with an internal thermometer that will measure the temperature of
the electrolyte and will include a conversion scale to correct the float reading. It is important to recognize that
the electrolyte temperature is significantly different from the ambient temperature if the vehicle has been
operated.
Using A Hydrometer
1. Draw electrolyte into the hydrometer several times to permit the thermometer to adjust to the electrolyte
temperature and note the reading. Examine the color of the electrolyte. A brown or gray coloration indicates a
problem with the battery and is a sign that the battery is nearing the end of its life.
2. Draw the minimum quantity of electrolyte into the hydrometer to permit the float to float freely without
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Owner's Manual and Service Guide