C&D Technologies RS-2061 Standby Batteries for Renewable Energy Applications User Manual

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Cycling Battery Charging Chart

Float Applications
Batteries in back-up power applications are constantly charged. In most cases, a constant voltage charger

maintains the float voltage. Under these circumstances, the battery is fully charged when the cell voltage has

reached its upper limit and the charge current has dropped a float current. These systems are rarely

discharged, but should they, it is critical that they are immediately recharged to a full state of charge.

Utilizing the constant voltage charging algorithm will result in a full charge battery after the charging current

has dropped to a float current as described in the following chart.

Equalization Charge
Proper charging in the mode described above will generally maintain the battery and equalization charge

will not be required. The latter is required only if the cell voltage spread, measured at the tail-end of the

refreshing charge, is such that the tolerable low limits (+/-50 mV of string avg.) are not attained. Typically,

equalization charge requires holding at the nominal string voltage in the refreshing charge mode for an

additional 8 to 12 hours. The total overcharge during this procedure must not exceed about 10% (i.e. extend

refreshing charge an additional overcharge of 10%). As before, the overcharge is based on the nominal AH

capacity utilized for computing the SOC. Use the Weekly charge Voltages the Cycling Battery Charge Table.
At the tail end of the equalization charge, and while still on charge, the cell voltage spread should be checked.

All the individual cell voltages should now conform to within +/-50 mill volts of the string average. If the

individual cell voltages exceed +/-50 millivolts of the system average, verify cell gravities where applicable and

contact a C&D Technologies Manufacturers’ Representative.

Float Battery Charging Chart

CPV Models
VR Solar

D, K, L - CPS-A
D, K, L - CPS-D

2.55 Vpc

13.62 to 13.80 VDC/Unit Average

2.50 Vpc
2.43 Vpc

2.50 to 2.55 Vpc

14.4 to 14.8 VDC/Unit Average

2.50 to 2.55 Vpc
2.43 to 2.47 Vpc

Battery Series

Daily Charge at 77°F (25°C)

Weekly Charge at 77°F (25°C)

CPV Models
VR Solar

D, K, L - CPS-A
D, K, L - CPS-D

2.28 to 2.33 Vpc

13.62 to 13.80 VDC/Unit

2.33 to 2.34 Vpc
2.20 to 2.27 Vpc

Battery Series

Float Charging at 77°F (25°C)

RS02061/0514/CD