Baroness FS900, Service Manual, Page: 79 / 163

Measurement
Battery
Measurement of Battery Specific Weight
Specific weight of electrolyte tends to reduce
in linear proportion with the discharged
electrical quantity of the battery and so
checking the specific weight of electrolyte with
a hydrometer can tell the remaining capacity
of the battery.
Temperature compensation is required for the
specific weight measured with a hydrometer.
The standard temperature for the specific
weight of battery electrolyte is 20 ° C, and the
specific weight increases or decreases by
0.0007 in accordance with the temperature
change of 1 ° C. Thus it can be compensated
by the following formula.
S20 = St + 0.0007(t - 20)
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2
3
lyp58z-002
Measurement of Battery Specific Weight_001
1 Specific weight converted for 20 ° C
2 Measured specific weight
3 Fluid temperature at measurement
Specific weight and remaining capacity of battery
Specific weight
(20 ° C)
Discharged
electrical quantity
(%)
Remaining
capacity (%)
1.28 0 100
1.24 25 75
1.20 50 50
1.16 75 25
1.12 100 0
Measurement of specific weight of 12V
battery
Check all the cells after charge.
Replace the battery when the specific
weight is 1.225 or less, or gap of that
between each cell is 0.05 or more.
1
lyp58z-001
Measurement of Battery Specific Weight_002
1 Cell
Battery charging
Follow this procedure to fully charge the
battery.
Warning
When charging the battery, do not use a
current in excess of one tenth of the rated
current. With regard to the maximum
recommended charging current, follow the
battery manufacturer's instructions.
Caution
If the battery gets extremely hot or releases a
significant amount of gas during charging,
unplug the battery charger at regular intervals.
Use a taper battery charger, which
automatically reduces the charging rate
during charging.
After charging is completed, fill the battery
cells with distilled water (if the battery is in
use).
After charging is completed, measure and
record the specific gravity of each cell using
a battery hydrometer. (See "Measurement
of Battery Specific Weight" (Page 5-5) )
If the measured specific gravity is 1.225 or
less, or the difference between the cells is
equal to or exceeds 0.05, replace the
battery with a new one.
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Electrical system
FS900
Electrical system
Page 5-5
Measurement