Single - Module DC Systems The simplest of systems is perhaps the most suited for low-cost rural electrification. A single module is connected to a single low cost battery through a simple charge regulator. The regulator has terminals for connecting to a fluorescent light. The regulator might have a low voltage alarm or even a relay that could turn off the light if the battery voltage became too low. The user would have to wait until the module charged the battery back to an acceptable intermediate voltage before he could turn on the light again. The battery could be a commonly available automobile battery. It wouldn't be expected to have a long life, but its low cost would allow the initial system price to be acceptable. Replacing the battery every year or so could be an acceptable price for clean, reliable, safe lighting.

Simple DC Systems

Personal water delivery systems are possible using only one or two modules connected directly to a DC water pump. Many models are available in 12 or 24 volt designs. The pump can be a surface mounted design, or a water-proof submersible type that is lowered down a well or borehole into the water. A maximum power tracking device might be connected between the module and the pump to maximize the electrical match and the energy transferred, but this is not essential. During summer months when more water is typically needed for drinking or irrigation and livestock, greater solar isolation means that more water is pumped automatically.

Large DC Systems Larger systems can be designed by adding more modules and batteries. A larger charge controller would be needed to handle the increased current flow from the array. Again, some DC loads could be connected directly to the regulator. But if the load circuits were too numerous, a DC circuit breaker distribution box could be used to allow connection of multiple load circuits. print page