Now that the project ambitions have grown beyond a little 1.5 W solar panel from Harbor Freight (Item #62449) the hunt is on for something larger. The 1.5 watt panel is intended to trickle-charge automotive batteries and is sized well for the job. We’re aware of much larger multi-kilowatt installations for household rooftop solar. What kind of market would support solar equipment in between that range?
One answer is the outdoor activities market, where some people desire a bit of electric power while away from civilization. Cell phones won’t work in the wilderness but there are still other reasons to have a power source: LED lanterns, GPS equipment, and cameras to document the adventure. The products designed for this market place focus on size and weight, important for carrying in a backpack. But since those values aren’t important for the current experiments, there’s no reason to pay the corresponding price premium.
Another answer is the market of people who want a less rugged experience away from home: boats and RVs. While these leisure vessels have power generators, supplementing them with solar panels reduce fuel consumption and associated noise and fumes. For this market there isn’t much desire to make trade-offs for size or weight, and so we can get more watts for the dollar.
Which brings us back to Harbor Freight who offers two products for this market. A small single 15 watt panel (item #96418) or a larger package featuring an array of four 25 watt panels plus a controller module (item #63585). The constantly varying world of Harbor Freight coupons means the exact dollar-per-watt changes for any given day. But the general trend is clear: between the 15 watt kit and the 100 watt kit, we pay roughly double the money for over six times the power plus a control module to treat the battery properly. The choice was easy to make.