Exide Technologies GB4007 - Manual (Page 2)

Determine the maximum voltage that may be applied
to the system equipment. This voltage, divided by the
number of cells connected in series (16 cells per battery
tray) will establish the maximum volts per cell (VPC) that
is available.
Table A lists the recommended voltages and charge
times for the initial charge. Select the highest voltage the
system allows to perform the initial charge in the shortest
time period.
TABLE A
Initial Charge (77°F)
Volts per Volts per Time-Hrs
Cell Battery (Minimum)
2.30 36.80 24
2.35 37.60 12
NOTE: Time periods listed in Table A are for77°F (25°C).
For other temperatures, a compensation factor of 0.003
V/°F (0.0055V/°C) per cell is recommended. The minimum
voltage is 2.20 VPC, temperature correction does not
apply below this voltage. The maximum voltage is 2.35
VPC, temperature correction does not apply above this
voltage.
V
corrected
= V
25°C
- ((T
actual
- 25°C) x (.0055V/°C))
or
V
corrected
= V
77°F
- ((T
actual
- 77°F) x (.003V/°F))
See Section 6.0 Voltage Regulator for recommended float
voltage ranges at various ambient temperature ranges.
4.0 INSTALLING THE BATTERY (BLOCKING)
Negligence in properly blocking the battery in the
compartment could permit battery shifting and may cause
damage. All trays should be securely blocked, but care
should be taken to avoid over tight wedging. Clearance
of about 1/8” should be left between the blocking and the
battery trays.
5.0 TERMINAL CONNECTIONS
Make original connections clean and tight. Inspect
terminal connections regularly and keep them clean and
tight. Corrosion can be reduced by greasing connections
with “NO-OX” grease after cleaning with household
ammonia or baking soda in water (1 lb/gal water).
6.0 VOLTAGE REGULATOR
The battery is only one part of a total system, all of the
parts of which are interrelated and interdependent. The
battery simply stores energy in a chemical form for use
when the generating system is not running. It is not a
source of power, but merely a reservoir. The battery
supplies power for starting, but as soon as the engine is
running, the generating system must replace the power
withdrawn from the battery.
Input from the generating system to the battery is
controlled by the voltage regulator. It is important to make
sure that the regulator is known to be in a satisfactory
operating condition and adjusted to the correct operating
voltage.
If the voltage regulator is not in good operating condition
or is adjusted to an incorrect operating voltage, the
battery will not function satisfactorily because the charge
it receives will be insufficient (undercharge) or excessive
(overcharged). In severe cases of bad regulation and
overcharging, failure can take place within a year.
A bad regulator or one set too low can cause undercharge
– a condition that will literally starve the battery to death.
In this case, more power is drawn out of the battery than
is replaced. As a result, the battery gradually runs down
until it is so low that it fails completely. Undercharge is
indicated by decreasing open circuit voltage readings.
The correct operating or battery float voltage to be set
on the regulator is that which will maintain the battery in
a fully charged condition. This correct setting depends
on two factors – operating temperature and locomotive
work schedule. It is recommended that voltage regulator
adjustments be made while the engine is at operating
speeds.
See Section 7 for temperature compensated operating/
float voltages.
7.0 OPERATING VOLTAGES
7.1 Single Step Charging
Correct battery float voltage at different environmental
temperatures are as follows:
Temperature Float Voltage
(Volts per Cell)
Greater than 90°F 2.20 – 2.23
65°F to 90°F 2.23 – 2.27
50°F to 65°F 2.27 – 2.31
Less than 50°F 2.31 – 2.35
The effect of the locomotive work schedule on the correct
float voltage is determined with experience. If the battery
is used for starting very frequently, float voltages should
be set at the higher end of the range indicated at the
appropriate temperature; similarly, for infrequent battery
usage, float voltages should be set at the lower end of the
range.
7.2 Two Step Charging
For two step charging the following strategy should
be followed:
Bulk Charge: Charge at temperature compensated
constant voltage between 2.33 and 2.38 vpc. Charge
for 6 hours or until current decreases to
Current
stated in Table B or until temperature reaches 104°F
(40°C). Switch to float charge.