We have run our solar panel with a battery we purchased from Wal-Mart and a microcontroller-based power controller of our own design for five years, and decided it was time to upgrade. The circuitry of our controller was a bit too much of a load for the application. For more information on the microcontroller based power controller, see PV System on the Cheap. We looked at a bunch of different power controllers, but the one that we decided on was the SPC2 available at CirKits Solar Kits. The controller was more than enough for our 50 watt PV panel. Here is what the kit looked liked when unpacked:

Here is what the new power controller looks like assembled:

Assembly was fairly straightforward. The instructions were good. The board has plated through holes, thick pads, and a nice solder mask. Don't purchase this if you haven't soldered before. If you have the skills, though, this is a good option for a small solar power PV system. One nice thing is that the parts are very standard, so if you need to repair this in the future it will be quite easy to get parts.