| SERRO SCOTTY CAMPER ENTHUSIASTS SOLAR POWER |
| HERE IS AN ARTICLE I FOUND AT CAMPING WORLD ABOUT SOLAR POWER FOR RV'S AND TRAVEL TRAILERS, I'M LOOKING FOR MORE INFORMATION, AND CHECKING TO SEE IF ANYONE IN THE GROUP HAS DONE ANY SOLAR IN THEIR CAMPERS, AND WILL POST AS SOON AS I GET SOME INFORMATION. “The sun will come out tomorrow.” These lyrics from the Broadway musical Annie ring true when it comes to the subject of solar power today. Developed in the 1960s to provide a renewable power supply for satellites, the application of photovoltaics technology, also referred to as PV, is as close and available for the RV enthusiast as your nearest Camping World store. To understand how photovoltaics work involves a trip into the world of the abstract to learn about what’s contained in sunlight and the evolution that takes place in the silicon wafers of a solar panel. Here’s how the technical gurus explain it. Within sunlight are particles called photons, which, upon penetrating the silicon wafers, bump against electrons in the silicon, generating direct current (DC). The amount of DC generated is contingent on the time of day, the angle of the solar panel relative to the sun and whether there are haze, clouds or other obstacles between the sun and the solar panels. Each wafer, operating at maximum performance, generates a 1¼2 volt DC. But because the wafers are wired in series, the voltage that comes out the other end and charges the battery is cumulative, creating an effective charging voltage for the battery. So in a 100-watt solar panel, each silicon wafer is generating a small number of watts; but when added together, it generates a total of 100 watts. If you mathematically converted the watts into amps, this would equal about 22 to 26 amp hours a day. It’s important to understand that some RV equipment operates using only DC, such as the house-water pump and lights. Power for these DC-powered items comes from the battery and is typically 12 volts. Other RV equipment requires alternating current (AC). When using the battery as the power source for AC appliances, DC is drawn from the battery and put through an inverter where it is turned into AC. Some of the smaller solar-powered systems with panels require no controller. A controller is an over- charge protection electrical device that senses the level of voltage in the battery and stops the process when the battery is fully charged. Controllers are typically between seven and 21 amps. If a controller wasn’ t used to stop the flow of DC from the solar panels when the battery is fully charged, heat would build. Through the loss of battery fluid, the battery would be damaged. The controller also includes a diode, which acts like a check valve in a fluid system. It keeps electricity from flowing backward from the battery into the solar panels at night or if the RV is parked in a garage or under a cover. There are a number of solar- power systems available through Camping World, some of which are small and can be laid on the dashboard and plugged into the cigarette lighter or carried in a backpack and to maintain a charge on cell phones or notebook-computer batteries. Others are larger and provide a charge for house- battery maintenance while the RV is in storage or between outings. Larger solar-power systems are popular among those who camp in the boondocks and want to minimize the use of the genset for charging the house batteries. Solar panels are available in modules with a controller that allows the end user to begin with a single solar panel (module). If, and when, electrical demand and requirements grow, additional modules or panels can be added to the solar-power system. Up to three 100-watt panels typically do not require anything more than the original 20 to 21-amp controller. Very small solar-power systems, such as those used to charge rechargeable AA batteries or cell-phone batteries, do not require a controller. Solar panels have a long life — they last for decades. The life expectancies are 20 or more years. For example, some solar panels of 50 watts and larger come with a limited, lifetime warranty. Little, if any, maintenance is required with the exception of possibly dusting, wiping or rinsing debris from the surface of the panels. There are no moving parts, their system is silent and with a solar-powered system the need to run the auxiliary generator is reduced. Since solar panels don’t present electrical hazards at RV voltages, they are safe to use. There are some general guidelines that can help determine how many solar panels are required to meet your electrical needs. Keep in mind that solar panels come in various sizes that can range from one watt up to 100 watts. One- and two-watt solar chargers are used to recharge AA rechargeable batteries, cell phone and computer-notebook batteries. Typically, roof-mounted solar panels come in standard sizes of 5-, 15-, 30- , 45-, 50-, 75- and 100-watts. These are for the express purpose of supporting coach electrical needs — both DC and AC. To determine what your DC electrical needs are, here are some approximate amp-usage figures, which can be used as guidelines. Florescent lights use 1.1 amps; a 14-inch color television uses 7.3; circulation water pump, 4.0; a three-way refrigerator, 35.0; Fantastic Fan, 10.0; and a satellite receiver, 2.0 amps. Check the appliances for actual power requirements. After identifying all the DC appliances you may use in the course of 24 hours, add up the total amps. Keep in mind that you don’t use any appliance continuously, so you need to estimate the total time of usage. You may operate the water circulation pump for only half an hour each day, or the TV and dish for four hours a day. Take the amps of an appliance and multiply or divide it by the time it will be used (hours or portions of hours in the day), and this will give you the amp hours required to support the use of that appliance. Add the amp hours for all DC appliances together. This will give you a total for estimated daily DC power consumption. As noted, AC appliances also draw DC power from the battery, but first it’s passed through an inverter to make it into AC power. AC appliances typically require more amps to operate. For example a microwave oven uses 137.5 amps; a blender, 16.4; a computer, 4.6; a laser printer, 100; and a hair dryer, 125.0. Camping World provides helpful worksheets that will help you identify the appliance power usage for your RV. A 100-watt solar panel can yield 22 to 26 amp hours per day. A 15-watt solar panel can yield five amp hours per day. Solar panels that are 50 or 75 watts can yield 12 to 15 and 16 to 20 amp hours per day, respectively. So if a solar system includes three 100-watt solar panels, a maximum of 78 amp hours per day can be generated using the sun. Not bad! |
Note from Ken Scott , concerning solar power usage thanks Ken
The problem I see with the solar is that everything is geared toward
12 V, ie inverters etc. In my opinion, the only use for these 12 volt
panels is to keep a battery topped off. To replace the power used
during the night they are severely inadequate. The only cost effective
way presently to use solar power is in led lighting, not running tv's,
blenders and 100 watt light bulbs. What you need is power, not volts.
The led lighting has improved by leaps and bounds with the intro of 1,
3, and even 5 watt led's. They run off a lower voltage, around 3.5
volts to 4.5 volts for the bigguns. That means quicker charge times on
smaller voltage batteries. NiMh batteries charge very easily over lead
acid. Some have a 5C charge rating. What you take out you can put back
in. 12 volt lead acid batteries charge very inefficiently. Li-ion
batteries need fancy, complicated charging proceedures, Nicads have a
problem with memory. NiMh seem to have the best charging proceedures.
You still have to be very careful of overcharging, but they charge the
fastest, do not have a memory so you can charge them at any time, not
just when they are dead, and maintain a very flat 1.2 volts over its
charged life.
If you use 3 amp hours off of a NiMh you can put 3 amp hrs right back
in + trickle charging to top it off. That all means smaller, lower
voltage, higher output solar panels and easier less complicated
chargers. A 3 amp, 1.5 volt panel will charge that battery in 1
hr/cell + top off time. Think of it as a very bright garden light
system. I am in the middle of experimenting with the led lighting. I
have some 1/2 watt leds coming from ebay, I have a circuit that will
run a 3.5 volt led off of a single 1.2 volt cell. And it works. Pretty
cool. Big drain on the single cell battery though but the charge time
is minimal due to you are only charging a single cell, not 10 of them
as would be found in a 12 volt battery with a large internal
resistance. NiMh batteries can be found with a 12 AH rating @ 1.2
volts and a discharge rate over 3 amps/hr. Thats a good amount of
power out of a single 1.2 volt cell. As soon as I determine the light
output of the leds and how many you need to light a camper up I can
start on the solar charge circuits. I'll let you know how that works
out.
They now have flexible panels that wrap around anything. The latest
from the solar panel geeks is a paint - on solar panel. Wow. If they
can get that to work ....
ken
The problem I see with the solar is that everything is geared toward
12 V, ie inverters etc. In my opinion, the only use for these 12 volt
panels is to keep a battery topped off. To replace the power used
during the night they are severely inadequate. The only cost effective
way presently to use solar power is in led lighting, not running tv's,
blenders and 100 watt light bulbs. What you need is power, not volts.
The led lighting has improved by leaps and bounds with the intro of 1,
3, and even 5 watt led's. They run off a lower voltage, around 3.5
volts to 4.5 volts for the bigguns. That means quicker charge times on
smaller voltage batteries. NiMh batteries charge very easily over lead
acid. Some have a 5C charge rating. What you take out you can put back
in. 12 volt lead acid batteries charge very inefficiently. Li-ion
batteries need fancy, complicated charging proceedures, Nicads have a
problem with memory. NiMh seem to have the best charging proceedures.
You still have to be very careful of overcharging, but they charge the
fastest, do not have a memory so you can charge them at any time, not
just when they are dead, and maintain a very flat 1.2 volts over its
charged life.
If you use 3 amp hours off of a NiMh you can put 3 amp hrs right back
in + trickle charging to top it off. That all means smaller, lower
voltage, higher output solar panels and easier less complicated
chargers. A 3 amp, 1.5 volt panel will charge that battery in 1
hr/cell + top off time. Think of it as a very bright garden light
system. I am in the middle of experimenting with the led lighting. I
have some 1/2 watt leds coming from ebay, I have a circuit that will
run a 3.5 volt led off of a single 1.2 volt cell. And it works. Pretty
cool. Big drain on the single cell battery though but the charge time
is minimal due to you are only charging a single cell, not 10 of them
as would be found in a 12 volt battery with a large internal
resistance. NiMh batteries can be found with a 12 AH rating @ 1.2
volts and a discharge rate over 3 amps/hr. Thats a good amount of
power out of a single 1.2 volt cell. As soon as I determine the light
output of the leds and how many you need to light a camper up I can
start on the solar charge circuits. I'll let you know how that works
out.
They now have flexible panels that wrap around anything. The latest
from the solar panel geeks is a paint - on solar panel. Wow. If they
can get that to work ....
ken