|Typical Bracket Mounting|
Solar panels are, most commonly, aluminum framed, glass encased assemblies weighing around 30 lbs. They are usually mounted with "L" or "S" shaped brackets using holes drilled through the RV roof and then sealed. Some manufacturers and installers use what is essentially double-sided tape. Mind you, it's VERY strong tape, but still....tape.
|170 Watt Panel|
If you'll recall I needed at least 360 WATTS of panels to get the job done. I sent the measurements I had to the manufacturer and they sent me back some basic specs. Based upon the sizes I sent they configured 3 panels. A 170 Watt version shown here and 2 140 Watt versions. 1 of the 140 Watt panels is the same width as the 170 Watt, and the other is almost square. Together they added up to 450 WATTS(!) given my limited roof real estate. I was thrilled, more than I needed and they only weighed between 5 and 8 lbs each! Since they are SEMI-flexible they would conform to the contours of my roof. Mostly. More on that later on.
Originally my specs called for around 18 volts. I figured since I had a 12 Volt battery that 18 Volts would run a charger just fine. Being new at all this I hadn't looked any further into the system. yet...
WARNING: Science Content Ahead -
Imagine VOLTAGE is like water pressure in a pipe and AMPERAGE is the amount of water flowing. The Battery is like a water balloon you are filling. You need to have more pressure going into the balloon than the it has pushing back to get water to go in. A large quantity of water will fill the balloon faster. The longer the distance the water has to go the lower the pressure you have, so you get less water at the other end. Think of a long garden hose. At a lower pressure you can get a bigger hose to get the same flow. Ideally, you have enough Voltage to charge your battery and enough Amperage to fill it quickly.
Now that we have that straight, back to Solar Panels. In order to make my system work efficiently I had to figure out how far my power had to travel and make sure my "pipes" (wires) were big enough to get the job done. If you've even done any work to the 12 Volt side of your RV you'll know that wires come in all sizes. From tiny wires going to gauge lighting, up to the heavy duty ones connected to your battery.
|Table Shows Wire Size in AWG|
Science Content Concluded (Whew!)
Tune in Next Week for PART 3 where we will talk about mounting the panels and dealing with wire runs. How do monsoon rains figure into a "simple" solar installation?
Be Seeing You...Down the Road
Richard "The Wanderman"
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Read Part 1 of this series.