Once the Monoprice PowerCache 220 was connected to the Harbor Freight 100W Solar Kit (Item #63585), we have everything we need to gather a little bit of sun power and make use of it every day. Given the non-optimal solar panel position and the fact we’re close to the winter solstice, this is just about the worst case scenario for solar power. Nevertheless this system has been gathering enough power to keep all the battery-powered electronics in the house charged up. This includes daily use & charge items like cell phones, tablets, and laptop computers. Plus the occasional items like a digital camera.
There is much more we can do to improve performance of this system, but it has met a minimum level of satisfactory performance so we can leave it running as-is for a while and switch gears to other projects. The focus will eventually return to this solar power system and here are two candidate projects for later:
Physical tracking: the panels are currently just sitting indoors vertically set against a south-facing window. It was done as an easy nondestructive way to experiment. When it comes time to improve upon this configuration, we can build a more permanent outdoor installation that angles into the sun. Maybe even motorized sun tracking throughout the day!
Electrical tracking: at the moment, the solar panel output voltage is dictated by the battery being charged. This is convenient and simple to implement but not the most efficient. We can buy (or design and build our own) a “maximum power point tracking” (MPPT) charger that keeps the solar panel voltage at its most efficient level and transform that to the correct battery charging voltage. It costs some power to do this tracking & voltage conversion, but if implemented correctly, the additional power will more than offset the cost.
We’ll add these projects to the bottom of the “to-do” list. For now, behold the glory of electronics being charged by sun power.