Solar power is the conversion of sunlight into electricity, using photovoltaics.
Watch a video that explains how Solar Photovoltaics work.
The Solar Array is primarily responsible for recharging the batteries.
Mars presents a number of challenges for solar power:
A dusty atmosphere allows less sunlight to penetrate the atmosphere, and reduces the efficiency of the solar panels when dust settles on their surface. (See Mars Weather)
Low temperatures that adversely effect their efficiency
Mars' greater distance from the Sun than Earth means that only about 42% of solar radiation reaches Mars.
Sunset on Mars
Sunset on Earth
At left a close up image of damage on the Mars Rover solar panels.