5
Rev.12/31/97
D. Unattended Stations
D. Unattended Stations
The equalizing charge may be terminated automatically by a timer. Use the
manufacturer's recommended charge time for the cell type. Set the timer to
switch off the equalizing charge and to reconnect the float charge. In the
event that the manufacturer does not provide a recommended charge time,
3 days (72 hours) may be used as the charge time.
manufacturer's recommended charge time for the cell type. Set the timer to
switch off the equalizing charge and to reconnect the float charge. In the
event that the manufacturer does not provide a recommended charge time,
3 days (72 hours) may be used as the charge time.
A "check charge" for batteries at unattended locations may be used to determine if
equalization is necessary. With a "check charge," the battery is placed on
charge at the equalizing rate. After allowing 15 or 20 minutes for the rate to
stabilize, the voltages of individual cells are measured. If the highest and
lowest cell voltages (while on charge at the equalizing rate) differ by no
more than 0.04 volt, the battery does not require equalizing. The battery
should be equalized if the voltage differences exceed 0.04 volt. Use a digital
meter accurate to 0.01 volt. The test described above is effective in
charge at the equalizing rate. After allowing 15 or 20 minutes for the rate to
stabilize, the voltages of individual cells are measured. If the highest and
lowest cell voltages (while on charge at the equalizing rate) differ by no
more than 0.04 volt, the battery does not require equalizing. The battery
should be equalized if the voltage differences exceed 0.04 volt. Use a digital
meter accurate to 0.01 volt. The test described above is effective in
determining
equality of cell charge. However, the test cannot be substituted
for a hydrometer in determining
state of charge. All cells must be within 5°F,
the reason is described in paragraph 2.6, and the temperature must not
be below 55 °F.
1.3
1.3. VOLTAGE READINGS
VOLTAGE READINGS
Voltage readings should be taken in accordance with the following
instructions. N
Note:
Accurate voltmeters are critical for extending battery life.
Provide a digital voltmeter accurate to 0.01 volt reserved only for station
battery duty and calibrate it or send it out for calibration at least once a year.
This voltmeter must be treated with extra care; do not use a shop meter or
electrician's general-use meter for battery voltages.
battery duty and calibrate it or send it out for calibration at least once a year.
This voltmeter must be treated with extra care; do not use a shop meter or
electrician's general-use meter for battery voltages.
A.
A. Each Shift (Attended Stations) or During
Each Shift (Attended Stations) or During Routine Inspections (Unattended Stations)
Routine Inspections (Unattended Stations)
Check the voltmeter on the control panel to determine if the battery is being
charged at the proper voltage. Adjust the battery charging voltage if
necessary.
charged at the proper voltage. Adjust the battery charging voltage if
necessary.
B.
B. When Taps Are Changed
When Taps Are Changed
Check the voltage on the control panel when taps are changed on power or
station-service transformers. Adjust the battery charging voltage if
necessary.
station-service transformers. Adjust the battery charging voltage if
necessary.
C. During Equalizing Charge
C. During Equalizing Charge
Just before terminating the equalizing charge, measure the voltages of the
highest
voltage cell and the
lowest
voltage cell of the battery to the nearest 0.01
volt with an accurate digital voltmeter. The equalizing charge should be
continued if the voltage difference between the two cells is more than that
recorded for the initial charge.
continued if the voltage difference between the two cells is more than that
recorded for the initial charge.