RS02250/0717/CD
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8.3 Equalize or Freshening Charging
8.3.1 Equalize or Freshening Charge Float Charge Applications
Under normal float charge operating conditions, it is not necessary to equalize or freshen the Liberty 2V
batteries when used within the criteria described in sections 5.2 and 7.
NOTE:
Some hydrogen gas may be liberated
at equalize charging voltage.
An equalizing charge should be performed if individual cell voltages fall 0.05 volts below the average float
voltage as specified in Table 1 (Section 7.1). Presence of a minimum voltage does not imply a battery is
malfunctioning or that it will not provide the necessary power when called upon.
NOTE:
Charging current to the battery should be limited based on the Ampere Hour capacity of the battery.
Refer to Table 1 for maximum charging current.Higher charging current could potentially destroy the
battery by overheating that subsequentlycauses more current to flow creating a cycle sometimes
referred to as “thermal runaway”.
8.3.2 Equalize or Freshening Charge Cyclic Applications
In cycle charge applications, depending on how the system is designed the batteries are regularly discharged
and regularly re-charged. In these applications, the charging system should be sized so that, on the average,
the battery is returned to between 85 to 90% state of charge daily. On a bi-weekly to monthly basis the battery
should be charged to 100% or fully charged state using the equalization parameters outline in Table 1 (Section
7.1) for equalization/freshening charge for 2V Liberty AES.
If the system is a solar-only system then the charging strategy is solely based on the photovoltaic panels
returning all of the energy to the battery every day. The ratio to the photovoltaic array to the load during the
worst conditions should be able to bring the batteries to full charge at least once a month.
If the system is a hybrid system where there is dispatchable battery charging capability, the batteries should be
charged to between 85 and 90% of full charge on a daily basis (daily charge). Monthly they should be given an
equalization charge to insure that they were fully charged and the SoC is reset.
NOTE:
Use the equalize voltage setting as shown in Table 1 (Section 7.1) for a period not exceeding the
specified hours depending on service conditions.
Consult your C&D Technologies Representative for additional information.
