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Small Cabin Solar
Remote Power
Small cabins, RV's, Marine and other remote power needs are easily provided by 12 volts DC batteries recharged from solar panels. To determine how many panels you need and the size of the battery bank depends on the amount of power used and how long you will require it. For powering some lights, a small TV, and other items, one to two 50- to 75 watt panels and a good heavy duty deep-cycle battery bank will probably suffice. To be able to run microwaves, toasters, hair dryers etc… a larger battery bank, good inverter and more solar panels will be needed. First and foremost it is a good idea to first reduce your power requirements by using energy efficient appliances, efficient lighting like compact fluorescent bulbs or the "Thin-line" line of 12-Volt fluorescent lights and other energy management schemes. Here are the major components in an independent energy system and some options to consider in designing such a system.
Batteries
How much battery: Your battery bank is the most important feature of your independent energy system as it is what you will be using to draw power from. The bank should be sized as to provide for up to 3 days of no solar production. These can be 6 or 12 volt deep cycle batteries in a 12 or 24 volt configuration. It is important to start with the size battery bank you will need as it is not easy to add to this once in use. Batteries of different types do not work well together either. A storage capacity of 200 amp-hours minimum should be adequate for most RV's, depending on how many appliances you want to power affects the battery bank size. We usually add a factor of 30% to this number as insurance.
 
You can get an approximate idea of how much battery you need (in amp-hours) by figuring out how many watts you need per day and multiplying this by 7 to provide for adequate battery storage. To figure the watts you use, multiply the volts or each appliance used times the amps - so a 12 volt light that pulls 3 amps will use 36 watts per hour. A 12 volt battery that can supply 100 AH or (12 x 100) 1200 watts and power that 36 watt light for about 20 hours. It is easy to figure your ideal battery bank size, we have forms and can assist you in this determination.
Controllers and Power Converters
The Solar Charge controller regulates the power input from the solar panels to the batteries and maintains the batter charge in optimal state. We like to use ones with load diverters that can be used to divert excess solar energy to heat water, power lights or power other devices instead of dissipating the power once the batteries are charged. In addition many RV power converters are of low quality and should not be used on expensive solar batteries. A good charge controller will save money over the long run. Solar panels or a good three-stage charger/Inverter are a better option since they vary the charging rate yet provide for quick recharging of the batteries at the same time as providing for maintaining battery health and useful life.
Inverters
You will most likely want an inverter. Large inverters should be as close to the battery bank as save on cable costs and minimize voltage drops. Small inverters are pretty reasonable, and will handle light loads up to 300 watts for around $100. These smaller inverters are less efficient and will use power when not even in use. A larger inverter (800-1500 watts) can run the microwave or coffee pot and cost from $150 to $300 and upwards depending on quality and features. Inverters from 600 to 1500 watts are the most popular. We offer many kinds with various features. Inverters are often packaged with fuses and safety disconnects and meters in a power panel. This is a convenient way to go and simplifies the wiring needed. Simply add the solar panels, batteries and ground and you are ready to roll. An example of a standard system including solar panels, batteries, controls, a good inverter, and fuses needed for full time living a complete system can easily cost from $1800 to $5000. The most popular sized system consists of 150 to 600 watts of panel, a set of two to eight 12-Volt deep cycle batteries, a charge controller with load-diverter, and an 600 to 1500 watt inverter for AC loads. By code, there should always be a fuse or breaker between the battery bank and the inverter. We use a DC rated circuit breaker.
Solar and Generator Systems
Solar power and a Generator: Many people run a dual system. They use the solar power most of the time for small loads employing a 300 to 600 watt inverter to run TV's, computers, and other small appliances however not all at one time. A generator is then used for the heavier loads. It can make sense and reduce your initial investment to have this arrangement and we can integrate a generator in the power system as a manual or automatic back-up. This generator is used for heavy loads and to occasionally charge your batteries when there is not enough solar energy. In the case of most RV and cabins, the periods between uses are usually adequate for the solar panels to recharge the batteries. In some cases a wind generator can provide added energy production and can work with solar once again to charge batteries.
Mounts
Mounting the solar panels should provide for easy of alignment with the Sun. Flush or tilted mounts are available. On cabins and RV's it is necessary to meet wind load requirements to ensure you panels do not become loose in high winds. This ranges from 70 to 100 miles per hour winds. Universal mounts and custom fabricated ones are also an option. In an RV, the panels should not be left tilting during traveling due to wind load.
RV Kits
We sell Shell RV kits along with RV kits from Sunwize and Unisolar. These range from one to 3 panels with some being unbreakable. RV's are an excellent user of solar power due to the existing 12 infrastructure it is easy to add solar and enjoy the benefits every time you drive. Rv kits start as low as $499 for single panels. A starter system can be as simple as a single panel, mount, and charge controller if you have batteries already.
Example system for RV or cabin
·2 to 6 BP SX-75 75 watt solar panels
· A 15 to 50 Amp efficient charge controller with load diverter
· 2 to 8 12 volt deep-cycle batteries 110 amp hour or more
· Disconnects, Fuses and Grounding
· Meters and safety protection
· Solar Panel mounts as needed
The total cost can range from around $800 for a small "starter" system, up to $5,000 or more for a large system with a pure sine wave inverter. The total energy output for this example system ranges from 900 to 1600 watt-hours per day depending on demand. Once again system sizing and design is important to provide enough power to run most standard RV lights and appliances with no problem, and allow the use of desired AC appliances in a safe and adequate way. The exact cost would depend on the number and kind of components used. See system diagram below for more details.

Typical Solar Energy System
Solar Economics
Going solar is an investment that pays dividends for years to come. Once the initial investment is made you immediately start saving on utility power, generator fuel, wear and tear and maintenance of a generator not to mention the hassle involved. You will also enjoy the quiet power solar provides, have very little maintenance and provides energy security and isolation from price increases. It is an investment in your future and an idea whose time has come. Many people are installing small systems in homes to provide for back-up power in case the utility line goes down again. Whatever your justification, Solar power is easy to do and live with. There are also tax advantages to installing an independent power system.
 
To explore how an independent energy system can work for you we need to start with your current power needs and size a system that will replace part or most of this power need. In a RV or remote cabin, the power source will most likely be a generator. Over the course or a year, the cost of running a generator can easily have paid for part or all of a comparable solar energy system. Another factor to consider is the constant increase in cost of utility power along with frequent power interruptions. An investment in your own independent power system provides peace of mind, peace of budget and decreases pollution and dependence on foreign oil. Give us a call today for a free site analysis, energy audit, and product demonstration.

Prices from $1000 to $2500 depending on options and number of panels/batteries. Harvest Solar & Wind Power, renewable solutions to everyday needs- power, hot water, lighting, water pumping and products that save. www.harvest-energy.com 918-743-2299

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