PV Powered Barn Lighting System

A simple off-grid one sun photo-voltaic system. - Which is a fancy way of saying that I want to put some lights in my Barn but don't want to run AC wires out there. This might be typical of an application worth doing for reasons other than cheaper power generation. I purchased a 45 watt panel set off of EBay, tossed out the controller, which was basically useless. Experimented with some different charge controllers and came up with a good battery charger that can power some low power lighting and a small (300 watt) psuedo sine wave generator for the occasional AC requirement in the barn.

I spend a fair amount of ink on this site doubting the value of PV for home electric power. However, there are certainly situations in which PV becomes much more attractive. Generally speaking PV becomes much more affordable whenever the options for power from the utility grid are expensive. In these cases, PV is a completely solid state (read reliable), tried and true technology for generating electricity from the sun. PV's poor generation efficiency means a slow pay back on a large investment which is its main drawback. However, if the alternative also requires a large investment in the form of placing power poles, or long wire runs, this changes the equation a lot. Comparatively speaking the initial investment is reduced.

In the case of my barn, I wanted a single low current circuit out there. However, my house breaker box in full and already above capacity. To run a wire to the barn I would have the cost of the wire, the cost of upgrading my breaker box, the expense and work of burying the wire. The 45 watt solar panel package was only $200.00. The charge controller was only $35.00. The Battery was $35.00. The inverter was $69.00. So the cost of the solar system was around $350.00. I would be hard pressed to do what needed to be done to run an AC circuit to the barn for the same cost.