Voltaic makes tons of solar-charging gear, from laptop bags to backpacks, but what are those living in a post-PC world to do? Well, the company just unveiled its Spark Tablet Case -- a thin, padded tote designed for your iPad or other slate that can generate 8-watts of power in sunlight. In addition to directly charging your iPad in about 10 hours, it can also bank the Sun's rays in a universal battery pack, for use when those fluffy things in the sky don't cooperate with your outdoor computing schedule. Optionally, the
