Yesterday we sat down and came up with the initial ideas to upgrade the original Solutions Cubed Solar Tracker. Below is the initial block diagram for the new design. This is the rough pass for what the new tracker will be able to accomplish. Basically, we will use the same 2-axis mechanical system with one full-size consumer solar panel on it. We will be able to then roughly follow the sun based on date and time along with the known installation latitude and longitude. From there, we will use a light sensor to fine tune the panel positioning. This is essentially an extension of what we have already done – the big addition will be the battery charging circuit.
While a typical battery charger is fairly straight-forward (we’ve done a few in the past for clients), a charger for a solar panel throws in a few more wrinkles. Specifically, you want to make sure that all of the power from the panel makes it to the battery. So you can’t simply step down the 35Vdc to a charging voltage of +14Vdc, as the power in the headroom is lost to the gods. An actual step-down transformer is necessary – basically we need to make a switching power supply. Cool.
To control all of this we are going to dive into a Propeller from Parallax. We have not used one before, but it looks real interesting. While it lacks a bunch of on-board peripherals, the eight, independent processors will make splitting the work between engineers pretty easy. More updates in the months to come.