Exide Technologies Section 95.10 - Manual (Page 11)

NOTE: Time periods listed in Table A are for temperatures from 21°C (70°F) to 32°C
(90°F); for temperatures 13°C (55°F) to 20.5°C (69°F), double the number of hours.
For temperatures other than 25°C (77°F) the following formula can be used to
determine the recommended initial charge voltage
per cell (VPC):
V corrected = V25°C - [(T actual - 25°C) x (0.003 V/°C)] or
V corrected = V77°F - [(T actual - 77°F) x (0.0017 V/°F)]
Example at 29.4°C (85°F) and at 24 hr. initial charge
V corrected = 2.40 - (29.4-25) (0.003)
= 2.40 - 0.0132
= 2.387 VPC
Raise the voltage to the maximum value permitted by the system equipment, but do
not exceed the maximum voltage listed for a given temperature.
When charging
current has tapered and stabilized (no further reduction for three hours), charge
for the hours shown in Table A or until the lowest unit voltage ceases to rise. Correct
charge time for the temperature at the time of stabilization. To determine the lowest volt-
age unit, monitoring should be performed during the final 10% of the charge time.
SECTION 9 - OPERATION
9.0 FLOAT CHARGE
In this type of operation, the battery is connected in parallel with a constant voltage
charger and the critical load circuits. The charger should be capable of maintaining the
required constant voltage at the battery terminals and also supply the normal load
where applicable. This sustains the battery in a fully charged condition and also makes
it available to assume the emergency power requirements in the event of an AC power
interruption or charger failure.
9.1 FLOAT VOLTAGES
Following is the float voltage range recommended for the RELAY GEL Battery System.
Select the “volts per cell” (VPC) value within the range listed that will result in the bat-
tery series string having an average volts per cell equal to that value.
RECOMMENDED FLOAT VOLTAGES: 77°F (25°C) = 2.25 VPC to 2.30 VPC
MAXIMUM CURRENT: 20A / 100 AH (20 hr rating to 1.75V@25C)
For temperatures other than 77°F (25°C) the following formula can be used to
determine the recommended float charge voltage
per cell:
V corrected = V25°C - [(T actual - 25°C) x (0.0055 V/°C)] or
V corrected = V77°F - [(T actual - 77°F) x (0.003 V/°F)]
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