TCM FB20-7 - Page 86

CONVERSION OF SPECIFIC GRAVITY AT VARIOUS
TEMPERATURES
The specific gravity of battery electrolyte varies with the
temperature. To know the correct specific gravity of the electrolyte,
you should measure the electrolyte temperature, too, and convert
the measured specific gravity into the value at the standard
temperature, using the conversion table.
The standard specific gravity of the electrolyte in a fully charged
battery is 1.280 at the standard temperature of 20°C.
How to read hydrometer
RUBBER BALL
HANDLING THE BATTERY
CONVERSION TABLE
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SPECIFIC GRAVITY AT 20°С
TEMPERATURE °C
Example:
Suppose the electrolyte temperature is 5°С and the hydrometer
reads 1.250. When converted into the specific gravity at 20°С,
the figure is 1.240, 0.040 lower than the standard value. Normal
charge is needed.