Stand-Alone Solar Lighting
Want to jump into the solar energy pool, but just don¡¯t know where to start and don¡¯t want to invest tens of thousands of dollars? Why not try a stand-alone solar light system? This is a small version of a solar power system that comes in kit form. It¡¯s a great way to familiarize yourself with the concepts of generating electricity from solar input, and it¡¯s an easy do-it-yourself project. From DIY Solar by Eric Smith, here is everything you need to know to get on board the solar bandwagon.
The kit used in this project is a 45-watt, 3-panel photovoltaic (PV) kit purchased from a large discounter. In addition to the three 15-watt PV panels, it includes two 12-volt lights, battery hookups, a combination regulator/charge controller/safety fuse, and an adapter plug for different DC appliances. To complete the installation, the only missing elements are a roof boot to seal the roof penetration for the panel wires (if you come through the roof ) and electrical conduit for the wire leads from the panels. You¡¯ll need enough conduit to get from the back of the panels to just above the regulator/charge controller.
You can set this up as a battery charging station for car, boat and RV batteries, or you can just install a permanent deepcycle battery and use it to power a few lights and DC chargers and appliances. You can also use the system to power AC appliances and lights, but you¡¯ll need to add a power inverter with a minimum capacity of 300 watts.
The PV panels slip into angled mounting brackets that can be placed either on a flat surface or a pitched roof. If you are working on a pitched roof, follow all safety precautions for working at heights and wear fall-arresting gear if the pitch is steep.
With the PV panels and a charge controller in place, this solar power generating station can do a lot more than just charge batteries, even without an AC inverter. Use it to supply power to a pond or waterfall pump, add a few DC lights, hook up garden lights, or just keep a few deep-cycle batteries charged up for emergency power in case the utility lines go down in a storm. If you live in the frozen north, it¡¯s also the perfect power source for an ice-fishing shack. Just plug in a DC-powered light, coffee maker and TV and you¡¯re good to go.
How to Install A Solar Light System
Locate the roof rafters, either by using a stud finder or by lifting up shingle tabs and tapping in finish nails. You must plan to fasten at least one of the angled mounting brackets to a rafter. If the other doesn¡¯t fall on a rafter, plan to attach it with toggle bolt anchors.
Predrill the holes for the mounting brackets, then fill them with roofing cement or silicone caulk. Fasten the brackets to the roof with neoprene screws (small lag screws with a rubber washer), or with toggle bolts if not attaching to a rafter.
Fit the bottom of the first collector panel neatly into the slot in the mounting frame assembly.
Lock the PV panel down into position by sliding the small bolt heads on the brackets into the keyhole slots on the back of the panel. (Other kits may use different fasteners.) Cover the panels with a drop cloth after they¡¯re in position¨Cthey¡¯ll start generating electricity as soon as the sun hits them.
Check the underside of the roof for electrical lines or ductwork. Locate an access hole for the panel cable into the roof deck, directly behind the panel assembly. Buy a flashing boot with a rubber boot sized for small electrical conduit (?¡± or 1¡å is best¨Ccheck online or at electrical or roofing suppliers if you have difficulty finding one). Place the boot so that the top edge extends under two shingle tabs, then drill a test hole with a ?¡± bit. Leave the bit in place and double-check the underside of the roof to make sure you come out in the right spot. If everything looks good, finish the hole with a hole saw or spade bit big enough for the conduit to fit through.
Cut a piece of conduit long enough to go through the roof and extend several inches above the boot. The conduit should continue on the underside of the roof over to the location of the regulator. Push the pipe through and hold it in place with a pipe strap or block of wood. Slip the roof boot over the pipe and wiggle it into place under the shingles. Spread roofing cement or silicone under the sides (but not the bottom) of the metal flashing, then nail it to the roof. Glue a 90¡ã elbow to the conduit, turning it downhill, and extend with more conduit (if necessary) to the back of the PV assembly. Fish the leads from the panels through the conduit to the regulator; you may need to use an electrician¡¯s fish tape for this job. Finally, plug the opening in the conduit around the wires with electrician¡¯s putty or caulk to seal out bugs and drafts.
Install two sturdy shelves inside the building to hold the regulator and the battery. The shelf should be easily reachable by an adult so the equipment can be turned on and off and plugged into the adapter easily. The battery shelf should be at least 18¡å off the ground.
Connect the wires from the PV panels to the solar terminals on the back of the regulator/charge controller. Secure the wires to the walls or roof framing members to keep them clear. CAUTION: The collector panels should be covered with a drop cloth or opaque material well before making these connections. Tape or clamp the drop cloth so it doesn¡¯t blow off.
With the regulator turned off, fasten the battery leads to the back of the regulator, then clamp them to the battery posts¨Cblack to negative first, then red to positive. Then uncover the PV panels. Double-check the connections, then turn the regulator/ charge controller on. For a 12V battery, the voltage output reader will show 13 when the battery is fully charged. This kit includes two DC lights. To install them (or other DC appliances), just plug the cord in to the proper port (or adapter) and turn the power on. Hang the 12-volt light fixtures from the rafters and then staple the cords to keep them secure and out of the way. Make sure to leave enough cord that the plug end is easy to insert and remove from the port. You¡¯ll plug and unplug the lights to turn them on and off.
Advances in solar technology have made many DIY-friendly products available to consumers, several of which will be hitting the market for the first time in 2011. These include solar water heaters, solar battery charging stations, solar powered lights, photovoltaic shingles that provide supplementary electricity, solar heat pumps, and solar panel kits that generate primary home electrical service. Among the step-by-step projects is a solar water heating system you can build and install yourself for under $1000; simple thermosyphon solar heat collectors for barns and outbuildings; or ¡°heat grabbers¡± that you can fabricate for $50 in materials and position below a south-facing window to provide auxiliary winter heat.
