All life on earth depends on the sun for heat, warmth, and energy. Solar panels allow people to capture the sun's rays to create electricity. But are solar panels operating at top efficiency?

Koa Tran's project (see Figure 1) tested how solar panels could be improved.

Figure 1: Project display for "Making efficient use of solar panels."

### Hypothesis

I believe that using bi-convex lenses, which concentrate a beam of light, will improve the efficiency of a solar panel.

### Independent variables

Lenses used on solar panels

### Dependent variables

Amount of voltage, current, and resistance

### Controls

• Time of tests
• Angle of solar panels
• Measurement tools

### Experimental groups

One 12-volt (v) solar panel with three bi-convex lenses connected in a clockwise pattern on three sides of the test solar panel

### Control groups

One 12v solar panel

### Materials

• Sunlight
• Three bi-convex lenses, measuring 5 cm in diameter
• Two 12v/15.24 cm x 17.78 cm x 2.54 cm solar panels
• Two built-in blocking diodes for solar panels
• Two 220-ohm resistors
• Two 60.96 cm x 60.96 cm x 0.7 cm wooden boards
• Two Radio Shack digital multimeters (voltage/ohmmeters)
• Three 68-cm wire hangers
• Three lens holders
• Four 357A 1.5 v button-cell batteries
• 500-cm tape ruler, 30.5-cm ruler, and protractor
• Solar calculator
• Connectors
• Brackets
• Tape
• Marker
• Tools

### Procedures

1. Set up experimental and control groups.

2. Place both groups outside at 8:50 a.m., when the sun's rays are striking the groups' location, at optimal angles to the sun.

3. For both groups, record the amount of voltages, without the resistors attached.

4. For both groups, remove the test leads and reset each voltage/ohmmeter.

5. For each solar panel, make contact between red and black test lead with the end wires of the 220-ohm resistor.

6. Record amount of resistance (in ohms) for both groups.

7. Take both groups indoors at 3:26 p.m., when the sun's rays are still strongly contacting with the solar panels and the bi-convex lenses.

8. Measure and record voltage, resistance, and current from each group; round the current and the voltage of each solar panel with the internal and external resistance to the nearest hundredths place.

9. Repeat experiment for the next two weeks, adjusting the times that the experimental and control groups are set out, after calculating the time for optimal sunlight.

### Results

Table 1 shows the average volts and milliamps for each test.

Table 1: Average Volts and Milliamps for Each Solar Panel

 Control Group Test Group Volts Milliamps Volts Milliamps Test 1 16.14286 5.85714 15.42857 5.15714 Test 2 17.00000 18.80000 16.85714 13.38571 Test 3 17.14286 31.84286 17.42857 20.51429

### Conclusions

My hypothesis was that solar panels using bi-convex lenses are more efficient than standard solar panels. My hypothesis was incorrect, because the experimental group with the bi-convex lenses actually reduced the amount of milliamps, voltages, and current that the solar panel received.

A future experiment would use mirrors in front of the solar panel rather than bi-convex lenses, which would increase the amount of sunlight coming into contact with the photovoltaic cells.