Solar Powered Spotlight

I'd like to discuss making a motion sensor spotlight that is solar powered. It will contain a battery that is charged during the day when the sun is out. This is great if you need light but don't want the expense or trouble of running power lines. It also means that the system is portable.The concept is simple. It consists of a 12 volt battery that is charged by a 2 - 5 watt solar panel. This battery is connected to a 75 watt inverter which, in turn, powers two compact flourescent spot lights (23 watts each). These spotlights are connected to a light and motion sensing base. The whole thing is in a wooden box to protect the battery and inverter from the weather and to make it more mobile.

Item Estimated Cost

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75 Watt inverter $25
12 volt car battery FREE
spotlight motion sensor $15
2 CFL spotlights (23 watts) $15
2 watt 12 volt solar panel $20
plywood for enclosure $10

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Total $85

The battery is just a 12 volt car battery you can pick up for free and desulfate (per my ebooks such as windmill or welding). With a solar panel less than 10 watts, you won't need a charge controller. You will have to place the inverter at the bottom of the box and make sure that the box is vented with small holes at the top. This is due to the corrosive gasses that come off the battery when charging or draining. Don't put big holes because birds will make it their home. You can also encase the inverter in it's own section with vent holes. All the vent holes should have a mesh or screen on the inside to keep bugs out as well. And make sure that rain can't get in. The handles are just pieces of rope put through holes and knots tied on the inside.

Richard