Exide Technologies Section 93.10T - Manual (Page 6)

TABLE A – Initial Charge Voltage per Cell
(VPC) and Time after Current
Stabilization for 1.215 and 1.250 SG TCX
TABLE B – Equalizing Voltage per Cell
(VPC) and Time after Current
Stabilization for 1.215 and 1.250 SG TCX
SECTION 6
6.0 SPECIFIC GRAVITY
6.1 The Specific Gravity (SG) of a fully charged battery is
1.215 ± 0.010 or 1.250 ± 0.010. Specific gravity is used to
determine the cell’s state of charge (SOC).
The value
decreases as the battery is discharged and increases as the
battery is recharged.
6.2 Specific gravity is expressed to the third decimal place,
e.g.1.250, and is measured by a hydrometer float enclosed
in a glass barrel/rubber bulb syringe. Holding the hydrometer
vertically, draw sufficient electrolyte into the barrel. The
reading should be taken when a) no hand pressure is being
exerted on the bulb and b) the float is not touching the side
of the hydrometer glass. The gravity is then read on the
hydrometer scale at the flat surface of the electrolyte. (See
Figure 1).
6.3 When making specific gravity readings, corrections must
be made for variations in the temperature of the electrolyte.
For each 1.67°C (3°F) difference in temperature of the
electrolyte above 25°C (77°F), add one point (0.001) to the
hydrometer reading.
Conversely, for each 1.67°C (3°F)
difference below 25°C (77°F), subtract one point (0.001) from
the observed hydrometer reading.
Example:
Reading
Hydrometer Cell Corrected to
Reading Temperature Correction 25°C (77°F)
1.253 20°C (68°F) -.003 1.250
1.257 30°C (86°F) +.003 1.260
1.254 35°C (95°F) +.006 1.260
SECTION 7
7.0 OPERATION
7.1 Operating the battery outside the specified float
voltage range can be detrimental to battery life and
performance. Failure to operate the battery within the
specified float range may void the warranty.
TABLE C – Recommended Float
Voltages @ 25°C (77°F)
7.2 Ideally, 108% to 115% of the ampere-hours removed
during discharge from a battery should be restored upon
recharge to insure 100% state of charge.
7.3 The battery should not be over-discharged. Do not
discharge the battery lower than 1.65 VPC for high rates (e.g.
15 minutes) or lower than 1.85 VPC for very low rates (e.g.
24 hours).
SECTION 8
8.0 CELL VOLTAGE VARIATION
8.1 Temperature. Cell voltage variation can occur due to
temperature. To properly analyze battery voltage uniformity
within the string, voltage readings should be corrected for
(battery electrolyte) temperature. The battery temperature
correction factor for voltage equals 0.003 volts for each
degree Fahrenheit (0.0055 V/°C) using a base 77°F (25°C).
Figure 1
4
Time (hours)
VPC 1.215 SG 1.250 SG
2.32 222 412
2.35 166 304
2.38 126 222
2.41 96 164
2.42 88 148
2.50 42 78
Time (hours)
VPC 1.215 SG 1.250 SG
2.32 111 206
2.35 83 152
2.38 63 111
2.41 48 82
2.42 44 74
2.50 21 39
SG Float VPC
1.215 2.17-2.25
1.250 2.25-2.35