ערכה סולארית

Educational objectives
• Studying the principles of solar energy, storage and conversion.
• Electrical measurements of different parameters.
• Analyzing and interpreting results.
• Studying the efficiency and impacts related to the positioning.

Suggested tutorials
One of the jumpers isolates the photo-voltaic panels from the rest of the electronics. In this way, students can measure
• The voltage in the no-load circuit (approximately 21V)
• The short-circuit current (approximately 1.9A)
• The current and the voltage according to the lighting, by covering one of the two panels or by varying the tilt of the kit's lid in relation to the sun by an angle α; and check that the power output is a function of the power factor
• Using a rheostat (e.g. ECO1/2-330), students can look for the charge which corresponds to a maximum power supplied by the panel
The second jumper measures the DC level delivered by the battery. The third jumper allows the current measuring at the converter’s input. Students can:
• Measure the no-load voltage and current at the converter’s input, and calculate the no-load power input
• Measure currents and voltages upstream and downstream of the converter and calculate the converter’s efficiency and losses by loading the 220V AC output.
• Check that the converter can supply up to 150W. Compare this power with the power supplied instantly by the panels. Draw conclusions about the role of the battery.
Angle of incidence of sun rays measurement
The solar kit VALSOL is supplied with a protractor and a simplified targeting system allowing the measuring (within a few degrees of precision) the angle of incidence of sun rays on the solar panels. This targeting system which is placed on side can be removed and stored in the side compartment dedicated to accessories storage. A stand (also removable) allows the stepless adjustment of the inclination of the solar panels.

When closed, the panels are protected against impact and scratches. The following can be found underneath the solar panel:
• a standard 15V DC 15 Ah Li-ion battery
• a 12V DC/220V AC, 50Hz, 150W converter
• a safety and monitoring electronics device

Control panel
• On/Off button
• a circuit breaker to protect against over-currents
• 4mm safety terminals for voltage and electric current inputs, with jumpers
• the converter’s On/Off button
• a 230V AC 50Hz socket with on and defect lamps
• a two-line LCD display delivering messages about the battery: temperature, % charge, charging current and voltage, usage current and voltage, undercharged battery, overcharged battery and overheating, etc., as well as the power output.
NB: these are indications, rather than highly accurate measurements.

PROTECTION OF COMPONENT IN THE CASE OF
• battery overcharge: when its voltage reaches 16.5V the charging current is automatically cut, in order to preserve the battery’s service life.
• excessive battery discharge: When its voltage reaches 11.5V, an audible alarm will be triggered.
When it falls below 10.5 V the output will be disconnected automatically.
• overload or short-circuit on the converter’s output

SPECIFICATIONS OF THE SOLAR PANEL
• Total surface area: 420 x 680mm  
• Total power: 30W
• Typical voltage: 17.5V      
• Typical current: 1.7A
• Short-circuit current: 1.9A      
• No-load circuit: 21.5V

OTHER CHARACTERISTICS
• Fitted side compartment for the storage of leads, jumpers, the targeting system and the inclination stand. Dims: 570 x 380 x 160mm. Weight 17kg.