Page 134 - Applied Photovoltaics

three systems, with total capacity of 720 kW p are under construction for installation in
the Northern Territory (Watt, 2004).

EXE RCI S ES

6.1 Discuss the use of batteries in photovoltaic systems, taking particular
consideration of:
x conditions faced by batteries when charged by solar cells
x the suitability of the various battery types to different applications
x the availability, costs, ratings and manufacturers of batteries in your
country.
6.2 Discuss the suitability of different wire and connector types commercially
available for a range of photovoltaic applications, including:
x the range of wires and connectors available that are potentially of use in
any photovoltaic application
x reasons for or against the suitability of certain types of wire and
connectors for specific applications
x lists of suppliers, prices, ratings and descriptions
x any applications or conditions for which suitable wires or connectors
cannot be found locally
x life expectancy of wiring
x any occasions when there is an economic-versus-suitability trade-off.
6.3 Draw a schematic of a stand-alone photovoltaic system, labelling each
component, then:

(a) Briefly discuss the function and reliability of each component and its
importance to the system.
(b) What are some of the more common problems that occur with each
system component?
(c) What factors affect the choice of battery type?

(d) How do you expect stand-alone system design to evolve in the future?
(e) In what ways may the climatic conditions have adverse effects on
system operation?
6.4 (a) In a stand-alone system, explain what problems may result from the
use of a regulator that short circuits solar panels. What relevance do
the system voltage and current have?
(b) Explain the concept of self-regulation as applied to battery charging
with solar cells.
(c) What problems may result from a system using self-regulation?
(d) Why do solar panels have open circuit voltages under standard test
conditions so far in excess of the nominal battery operating voltage?

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