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Rev.12/31/97
2.17 ADJUSTING SPECIFIC GRAVITY
2.17 ADJUSTING SPECIFIC GRAVITY
Specific gravity should never
never be adjusted until the gravity is definitely
established to be wrong. Before adjusting for low gravity, make sure that the
gravity cannot be raised by equalizing (see 1.2 C). Continue the charge
until the specific gravity shows no rise, and then charge for 3 more hours.
Hydrometer readings must be taken as indicated in 2.18 below.
gravity cannot be raised by equalizing (see 1.2 C). Continue the charge
until the specific gravity shows no rise, and then charge for 3 more hours.
Hydrometer readings must be taken as indicated in 2.18 below.
Never make a
gravity adjustment on a cell that does not gas on charge. Remove some electrolyte
from the cell and replace it with pure, 1.300-gravity sulfuric acid, which
consists of 30-percent concentrated acid and 70-percent distilled water by
volume. Recharge until all cells gas for an hour. Repeat the procedure if
the gravity is still not normal. To
consists of 30-percent concentrated acid and 70-percent distilled water by
volume. Recharge until all cells gas for an hour. Repeat the procedure if
the gravity is still not normal. To
lower
the gravity, replace some of the
electrolyte with distilled water.
2.18 HYDROMETER READINGS
2.18 HYDROMETER READINGS
Provide two hydrometers of high accuracy and sensitivity and check them
against each other frequently. The hydrometers should be replaced every 2
to 3 years. The hydrometer must be held vertically for accurate specific
gravity readings. Do not take readings after adding water (or acid) until the
to 3 years. The hydrometer must be held vertically for accurate specific
gravity readings. Do not take readings after adding water (or acid) until the
electrolyte has had time to mix thoroughly (not less than 1 hour when
gassing or 2 days if not gassing for antimony cells, and several weeks for
calcium cells in floating service). Use a long nozzle syringe and take
samples several inches down to minimize errors. Bubbles in the electrolyte
cause errors, and readings should not be taken sooner than 15 minutes after
gassing has stopped.
gassing or 2 days if not gassing for antimony cells, and several weeks for
calcium cells in floating service). Use a long nozzle syringe and take
samples several inches down to minimize errors. Bubbles in the electrolyte
cause errors, and readings should not be taken sooner than 15 minutes after
gassing has stopped.
Specific gravity of electrolyte must be corrected for temperature. Subtract
one point (0.001) from the specific gravity reading for each 3 EF the
one point (0.001) from the specific gravity reading for each 3 EF the
temperature is below 77 °F, and add one point (0.001) for each 3 EF the
temperature is above 77 °F. The recommended specific gravity spread
between all cells is 0.010.
between all cells is 0.010.
2.19 CONSTANT VOLTAGE CHARGING
2.19 CONSTANT VOLTAGE CHARGING
Constant voltage charging is the preferred method because of extended
service life. If charging equipment is suitable for a continuously floating
charge at a constant voltage, the proper floating voltage should be chosen
from the manufacturer's data. If the voltage is given for a single cell,
multiply this voltage by the number of cells in the battery.
service life. If charging equipment is suitable for a continuously floating
charge at a constant voltage, the proper floating voltage should be chosen
from the manufacturer's data. If the voltage is given for a single cell,
multiply this voltage by the number of cells in the battery.
2.20 BATTERY LIFE FOR DIFFERENT
2.20 BATTERY LIFE FOR DIFFERENT TYPES AND SERVICES
TYPES AND SERVICES
The life of various types of cells can vary markedly. Valve regulated lead-
acid cells have the shortest life. Formed plates of the Plante or Manchex
type on light duty and floating charge have a longer life, usually 14 to 18
acid cells have the shortest life. Formed plates of the Plante or Manchex
type on light duty and floating charge have a longer life, usually 14 to 18
years. Pasted plate Plante cells may be expected to last in excess of 25 years
on float charge. Formed plate cells, if cycle charged, usually last only about
9 years. Lead-calcium cells on constant float charge typically last 12 to 15
on float charge. Formed plate cells, if cycle charged, usually last only about
9 years. Lead-calcium cells on constant float charge typically last 12 to 15