Overview

To test the output of the solar panel, we first drained the onboard battery as low as we could get it with a high-draw Radio Control vehicle. We then set the buoy outside in the sunlight for a period of 7 hours and 20 minutes, checking the battery voltage before and after.

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Analysis

After draining the battery, we measured 7.0V between the battery terminals. We connected the battery to the Arduino on the buoy with the Arduino powered on, and left it outside at 10:40 am. At 6:00 pm, we checked the voltage of the battery and found that it had dropped to 4.75V. This is a 32.1% voltage drop. Our metric stated that the buoy’s solar cell charges the battery 80% when the UV index is 3-6 after 5 hours of sunlight, therefore we were not able to meet the metric. Since the testing was conducted during the winter in Terre Haute, the UV index was 3 that day. It is difficult to determine how the buoy will perform when the UV index reaches a higher range. For the future prototype, we will have to search for a way to conserve battery consumption by the Arduino to minimize the operating power requirement.