Page 108 - Alternative Energy Systems in Building Design

84 SOLAR POWER SYSTEM PHYSICS AND TECHNOLOGIES

Figure 3.43 Deep-cycle battery packs. Photo courtesy of Solar Integrated Technologies.

BATTERY POWER OUTPUT
In each instance when power is discharged from a battery, the battery’s energy is drained.
The total quantity of energy drained equals the amount of power multiplied by the time
the power flows. Energy has units of power and time, such as kilowatthours or wattsec-
onds. The stored battery energy is consumed until the available voltage and current
levels of the battery are exhausted. On depletion of stored energy, batteries are recharged
over and over again until they deteriorate to a level where they must be replaced by new
units. High-performance batteries in general have the following notable characteristics:
First, they must be capable of meeting the power-demand requirements of the connected
loads by supplying the required current while maintaining a constant voltage, and second,
they must have sufficient energy storage capacity to maintain the load power demand as
long as required. In addition, they must be as inexpensive and economical as possible and
be readily replaced and recharged.

BATTERY INSTALLATION AND MAINTENANCE
Unlike many electric apparatus, standby batteries have specific characteristics that
require special installation and maintenance procedures, which, if not followed, can