Demonstrate an understanding of the factors which influence the output characteristics of photovoltaic modules (irradiance, temperature, load, etc.)
As the temperature of a solar cell decreases how do the current and the voltage change?
Understand the operating principles of charge controllers and explain the major controller features (e.g. low voltage disconnect)
The only solar modules that are available have 36 cells. The battery bank for the system is 12V and the array will comprise a number of modules. What type of solar controller must you use for this type of system?
Demonstrate knowledge of correct units for electrical potential (voltage), electrical flow (current), electrical resistance, power, and energy
A DC load is connected to 24 V and the current is 2 A. What is the power of the load?
Demonstrate an understanding of the effect on array output (current, voltage, power) of connecting modules in series, parallel and series/parallel configurations
I am using a 150 watts solar module and nominal voltage is 12V. I have calculated I need a 3,000 watts solar array with a system voltage of 48V.
What will be the configuration of the array? That is how many modules in series and how many parallel strings?
Demonstrate the impact of shading on overall production of solar energy
The following is the hourly irradiation readings for a site where a solar array will be installed.
If the site is shaded from 11 AM to 2.00 PM what is the total available daily irradiation for the site?
Know how to properly use electric measuring instruments
If you were to measure the voltage across the 30 k resistor in the diagram below, indicate which diagram below would be the correct way to connect the multimeter into the circuit.
Understand the installation techniques for pole mounted as well as roof mounted PV arrays
When installing a solar module on a roof, things to be considered are?
Understand Ohm’s and Power Laws to be able to calculate energy load
A LED lamp rated 9 W is on for 40 minutes and TV of 60 W is on for 2 hours. How much energy has been used?
Understand the disadvantages of using dissimilar modules in the same array
What is the voltage and current measured at the output of the array below?
Interpret and explain different PV module and battery technologies, criteria for battery selection and major factors affecting battery performance characteristics
Name at least three factors that influence useful daily PV module output to the controller?
Answer: Any three of the following:
Demonstrate an understanding of differences between AC and DC power, power factor and true power vs. real power
A certain appliance has a true power rating of 300W and an apparent power of 400VA. What is the power factor of this appliance?
Understand basic operating principles of an inverter and list factors which affect efficiency and reliability of inverters
I have a 230 V AC appliance that is rated 600 Watts however it requires a surge current of 4 amps and the inverter we are selecting is rated at unity power factor. You have four inverters with surge ratings below to choose from, which inverter you would select to operate this appliance?
Demonstrate knowledge of basic electric circuit theory and be able to identify series, parallel and series/parallel circuits
In the following figure, assuming a total parallel resistance of 240 ohms and a battery voltage of 24 volts, what voltage will we measure across the points F1 & F2?