Alpha Technologies Lomain Ni-Cd Pocket Plate Battery - Manual (Page 22)

745-680-B10-001 Rev. A 22
5.0 Sizing method for standby applications
The Lomain Ni-Cd pocket-plate batteries used for standby floating applications are sized according
to the international sizing method IEEE 1115. A special battery sizing calculation program (available
at www.url here.com ) that allows sizing calculations to be made allowing for multiple discharges, and
factors such as temperature de-rating and aging.
A significant feature and advantage of the Ni-Cd battery in comparison to the lead acid battery is that
it can be fully discharged without any reduction in the lifetime or recharge of the battery. This feature
enables the battery to operate for longer periods between charges.
The most important sizing parameters are:
5.1 Voltage window
This is the minimum and maximum voltage acceptable for the system. The maximum voltage
provides the voltage that is available to charge the battery, whereas, the minimum voltage
gives the lowest voltage acceptable to the system to that the battery can be discharged.
5.2 Load profile
The load profile is the electrical performance required by the system from the battery for
the particular application. It can be expressed in terms of amperes for certain duration or in
watts for certain duration. The requirements might vary for example from just one discharge
to multiple discharge of a complex nature. In order to calculate the appropriated battery size
please take into consideration point 5.1 voltage window.
5.3 Ambient temperature
The ambient temperature will have in any case an influence on the sizing of the battery (see
Section 4.4, “Impact of temperature on cell performance available Capacity” and Section 4.5
“Impact of temperature on lifetime”).
5.4 Recharge time and state of charge
Some application might require a full discharge cycle of the battery after a certain time
after the previous discharge. The factors to be taken into account depend on the depth of
discharge, the rate of discharge as well as the charging conditions.
5.5 Aging
It might be required that a value has to be added to ensure the correct service of the battery
during the lifetime. The value to be used depends on the discharge rate of the battery and
on the conditions under which is carried out. Our experts or partners are able to help you
chosing the right battery for your special requirements.