User Manual

– 22 –
Charging Voltage
The charging voltage should be chosen according to the
type of service in which the battery will be used.
Generally, the following voltages are used:
In a constant voltage charging system, a large amount of
current will flow during the initial stage of charging but
will decrease as the charging progresses. When charging
at 2.275 volts per cell, the current at the final stage of
charging will drop typically to a value of between 0.0005C
Amps and 0.004C Amps. The charged volume in ampere
hours, shown on the vertical axis of Figures 10 - 15
(pages 14-16), indicate the ratio of charged ampere hours
to the previously discharged ampere hours. When a
battery has been charged up to a level of 100% of the
discharged ampere hours, the electrical energy stored
and available for discharge will be 90% or more, of the
energy applied during charging. Charging voltage should
be regulated in relation to the ambient temperature. When
the temperature is higher, the charging voltage should
be lower and conversely when the temperature is lower,
the charging voltage should be higher. For specific
recommendations, please refer to the section on
Temperature Compensation on page 25. Similarly,
charged volume (measured in ampere hours) realised
over a given time will vary in direct relation to the ambient
temperature; the higher the ambient temperature, the
higher the charged volume in a given period of time and
the lower the ambient temperature, the lower the charged
volume in the same given period of time. Figure 25 shows
the relationship between charged volume and
temperature.
For float (standby) use. . . . . . 2.275vpc ± 0.005 volts per cell
For cyclic use . . . . . . . . . . . . . . . . 2.40 to 2.50 volts per cell