C&D Technologies 41-7525 VRLA Batteries (rack mounted systems) - Manual (Page 15)

Battery Connection to the Load/Charger
Select the proper size and type of cable per the
NEC or other applicable code which can handle
the charge and discharge current related to the
battery. The cable size selected should also
consider the cable resistance per foot and the
voltage drop allowed between the battery output
terminals and the load.
The output circuit of the battery should contain
a DC rated fuse or circuit breaker to protect the
wiring and where appropriate a disconnect to
facilitate service to the battery in an open circuit
condition.
With the load/charger fuse, circuit breaker or
disconnect in the open condition, connect the
battery output cables to the load/charger circuit.
Parallel Connection of Individual
Battery Strings
When individual strings of batteries are to be
connected in parallel, each of the individual
battery strings should be cabled separately to a
common junction point or box. They should not
be daisy chained in parallel.
Each of the individual battery strings output
circuits should contain a fuse, circuit breaker or
disconnect prior to the common connection at
the junction point to protect the wiring and
facilitate battery maintenance.
When the separate strings of batteries are to
be initially connected in parallel their open
circuit voltages should be within 1 VDC of
each other prior to making the paralleling
connection.
Battery System Pre-Operational Checks
Prior to application of any freshening charge or
load to the battery system the following checks
should be performed as defined in the document
Operational Qualification and Warranty
Registration Checklist, Form #41-7471.
Battery Room and General Equipment Checks.
1. Battery Charger/Rectifier Checks.
2. Battery Rack/Enclosure Checks.
3. Battery Open Circuit Checks.
Initial Freshening Charge
When the batteries have been in storage or transit
for an extended period or the battery system is
intended for use at the minimum float charging
voltage or when the number of cells in series is
greater than 24, it is recommended the battery
system be given a freshening charge at 2.4 volts
average per cell for 24 hours. This will assure
higher initial performance and will reduce the time
period required for the cells to achieve proper
voltage balance between the individual units.
Document the progress of the freshening charge
in Section V of the document "Operational
Qualification and Warranty Checklist",
Form #41-7471.
To apply a freshening charge:
1. Confirm the freshening (equalization) voltage
from the charger/rectifier is set to a value equal
to 2.4 volts per cell x number of cells
connected in series (7.2 and 14.4 volts
respectively for 6 volt and 12 volt batteries).
2. Close the circuit from the charger/rectifier to
the battery system and note that the battery
accepts current.
3. Monitor the battery periodically and note that
the operation is proceeding normally and that
the current acceptance is declining, the batteries
are not overheating (within ±5 F of each other
and the ambient) and that the individual battery
voltages on equalization charge are 7.2±0.25
and 14.4±0.50 volts for 6 and 12 volt batteries
respectively.
4. Terminate the freshening charge in the event
of any extraordinary situations or after 24
hours.
Initial Float Charging
Following the freshening charge the battery
system should be placed on float charge at an
average voltage of 2.25 to 2.30 volts per cell (6.75
to 6.90 and 13.5 to 13.9 volts for 6 and 12 volt
batteries respectively).
Prior to placing on float charge, assure the
charger/rectifier is set to the proper output voltage.
41-7525/0514/CD 15 www.cdtechno.com