Exide Technologies Section 92.80 User Manual

Page 17

V corrected = V77°F - ((T actual - 77°F) x .003V/°F))

Please refer to Appendix A for standard values.

1. Set constant voltage charger to maximum setting without
exceeding 2.35 VPC.
Example: For a target charge of 2.35 VPC on a 24-cell system,
you would set the charger voltage to 56.4 volts.

Depending on the battery’s state of charge, the charger may go
into current limit at the beginning and decline slowly once the
target charge voltage is reached.

2. Record time and current at regular intervals – every hour as a
minimum.

3. Continue charging the battery until there is no further drop in
charge current over 3 consecutive hours. This could take days if
the battery has been in storage for a long time.

4. When the current has stabilized, proceed to step 2.

1. Continue the charge for the time listed in Table C depending
on the charger voltage setting. The time is IN ADDITION to the
time spent charging in Step 1.

Example: charge for 12 hours if the charger voltage is set to 2.35
VPC.

TABLE C

EQUALIZE CHARGE (77°F)

CELL VOLTS

TIME (HOURS)

2.30

2.33

2.35

2. Record cell voltages hourly during the last 3 hours of the
charge time. If, after the charge time has completed, but the low-
est cell voltage has continued to rise, you may extend the
charge, monitoring cell voltages hourly, until the lowest cell volt-
age ceases to rise.

3. Proceed to Step 3.

1. The initial charge is complete. Charger voltage can now be
reduced to float voltage setting per Section 13.2. For a target
float charge of 2.25 VPC on a 24-cell system, you would set the
charger voltage to 54 volts.

SECTION 13: BATTERY OPERATION

13.0

Cycle Method of Operation

In cycle operation, the degree of discharge will vary for different
applications. Therefore, the frequency of recharging and the
amount of charge necessary will vary. Generally, Absolyte GX

cells require approximately 105-110% of the ampere-hours
removed to be returned to a full state of charge.

The upper voltage settings recommended, given that the maxi-
um charge current is 5% of the nominal C100 Amp-hour rating
and the ambient temperature is 25°C (77°F), are as follows:

2.28 ± 0.02 VPC @ 0-2% DOD
2.33 ± 0.02 VPC @ 3-5% DOD
2.38 ± 0.02 VPC @ >5% DOD

Due to the variety of applications and charging equipment (par-
ticularly in photovoltaic systems) it is recommended that you
contact an GNB representative when determining proper
recharge profiles.

13.1

Floating Charge Method

In this type of operation, the battery is connected in
parallel with a constant voltage charger and the critical load cir-
cuits. The charger should be capable of maintaining the required
constant voltage at battery terminals and also supply a normal
connected 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.

13.2

Float Charge - Float Voltages

Following are the float voltage ranges recommended for the
Absolyte Battery System. Select any “volts per cell” (VPC) value
within the range listed that will result in the series string having an
average volts per cell equal to that value.

RECOMMENDED FLOAT RANGE (@77°F)

2.23 to 2.25 VPC

NOTE: Recommended float voltages are for 77°F. For other tem-
peratures a compensation factor of .003 V/°F (.0055 V/°C) per
cell is recommended. The minimum voltage is 2.20 VPC, tem-
perature correction does not apply below this voltage. The max-
imum voltage is 2.35 VPC, temperature correction does not
apply above this voltage.

TEMPERATURE CORRECTION

V corrected = V25°C - (( T actual-25°C) x (.0055V/°C)) or

V corrected = V77°F - ((T actual-77°F) x (.003V/°F))

See Appendix A for standard values.

Modern constant voltage output charging equipment is recom-
mended for the floating charger method of operation of GNB
Absolyte batteries. This type of charger, properly adjusted to the
recommended float voltages and following recommended sur-
veillance procedures, will assist in obtaining consistent service-
ability and optimum life.

After the battery has been given its initial charge (refer to
Section 12), the charger should be adjusted to provide the rec-
ommended float voltages at the battery terminals.

STEP 3

STEP 2

STEP 1