When fully illuminated, the Mars Exploration Rovers
solar arrays generate about 140 watts of power for up
to four hours per day. The rover needs about 100 watts,
the equivalent power used by a standard house light
bulb, to drive and carry out its daily tasks.
Comparatively, Sojourner's solar arrays provided around
16 watts of power at noon on Mars. That´s equivalent
to the power used by a single oven light.