I used a separately powered mbed microcontroller to read the voltage across the battery terminals every 15 minutes. The solar panel has good exposure to the southern sky out the back of my window. I regulated the voltage from the panel down to 5V because I found that the panel was putting out over 7.5 V in direct sunlight, and the charging chip was only rated for 6V. The charging board received the regulated 5V from the solar panel and connects both to the Lithium Ion battery and the load (resistor and LED). After 5 days, I imported the data to excel and plotted the results along with the weather conditions for the day.