Solar Power

Small project to demonstrate solar power, power storage in batteries, and a motor load to spin a propeller.

Parts

• 2x PowerFilm 4.8V 100mA photovoltaic modules
• 1x Low Voltage Schottky 1A Diode
• 1x Hitec 1600mAH 4.8V NiMH flat battery pack
• 1x Standard 030 form-factor RM1A 4.7V 150mA 7400rpm motor
• 1x Propeller 3.4"

Setup

The twin solar panel is providing 4.8Volt 200 mA power, the battery 4.7Volt 1600mAh, and the motor a 4.7Volt 150mA load.

NiMH (Nickle metal hydride) batteries should normally be charged at 1/10C rate, e.g. 1600/10, 160mA. That means it will take 10 hours to charge 1600mA. With maximum 200mA from the solar modules, it should be charged in 1600/200, 8 hours. That's about the average length of daylight.

If the motor is only used at night and free spinning, it should be able to spin 1600/150, 10.5 hours.

A diode will block the current from the battery to flow back to the solar modules when the sunlight is not bright enough to charge the battery.