Are you considering a solar electrical system for your home or business in Baja California Sur? Solar electricity is a wise investment. Here's why:
Compared to gas-driven generators or utility line extensions, solar electric power is clean and dependable, noise free, requires minimal maintenance, and is an excellent, affordable investment that adds to the value of your home.
A solar electrical power system is the best way to supply electricity anywhere, especially when you consider that bringing utility service to a remote location typically costs between $10 to $15 per foot; or between $50,000 to $75,000 per mile. Add to that initial cost the monthly fee for using the utility service and you can see why solar electricity makes sense. In addition, if you live at the end of the utility line, your service will typically be inferior to that of customers nearer to town.
If you live beyond the utility grid, solar power is a natural choice. More dependable and cheaper than hydro or wind power, and quieter than a generator (and zero pollution).
"How Big of a Solar Electrical System do we Need?" It's the most frequently asked question, and the most difficult for us to answer without more information. The first question that must be answered to determine system size is "How much power do you use/want to use?" We have developed a Home Energy Estimator to help you answer this question. Please contact us to request a copy.
A typical "off grid" solar system has four main components; the panels, batteries to supply energy overnight or during cloudy days, a battery charge controller, and an inverter to convert the panel and battery power to 120 volt AC. The rest of the system is composed of the panel mounts, connecting cables, and safety disconnects:
There are basically two type of charge controllers; PCM and MPPT. Typical PCM charge controllers will accept a limited range of panel configurations and voltages. MPPT charge controllers are able to accept a wider range of panel configurations and voltage and are more efficient by about 15%. They are also more expensive but their higher efficiency is similar to adding another panel in larger systems.
There are basically two type of inverters; modified sine wave and true sine wave. Modified sine wave inverters are cheaper but they can cause problems with computers, audio equipment, some motors, compressors and fans, and some types of dimmer switches. True sine wave inverters produce smoother power that is more similar to that provided by public utilities. In fact, the quality of this power is much better than that typically supplied by public utilities because it is free of the spikes, noise and brownouts that plague public utilities.
All good inverters have special internal circuits and battery chargers that can be connected to external power sources such as backup generators or public utility electrical systems. In the event of extended periods of low solar availability, these backup sources can then be used to provide supplemental power and/or to recharge the solar batteries.
There are basically two types of solar batteries; flooded lead acid (FLA) and sealed AGM. FLA batteries are more common and cheaper. They require regular maintenance to add water and to prevent corrosion. They also need venting to prevent their gases from accumulating to potentially explosive levels or causing corrosion to nearby equipment. Normally, they must be located in a separate compartment or box to isolate them from the other solar equipment. AGM batteries are more expensive but they can be installed anywhere as they do not produce explosive or corrosive gases. They are maintenance-free and do not need water. Weith proper care and maintenance, both types of batteries last about the same duration of 7 to 9 years. Note, due to price fluctuations on the spot market for Lead, pricing of batteries can fluctuate greatly.
Generally, larger panels are more cost effective because they are cheaper per watt, and it is a little cheaper to install one big panel rather than two small ones. Some panels are designed for off gird use while others are designed for "on-grid" systems where owners can sell electricity back to the public utility. The on-grid panels are slightly cheaper. MPPT-type charge controllers can use either type of panel equally well. Note, due to worldwide demand, pricing and availability of panels can fluctuate greatly.
Solar panel mounts should be well designed, and securely anchored and braced to the roof or ground to reduce the chances of hurricane damage. The misuse of simple concrete screws or percussion nails to secure panels to a roof is an accident waiting to happen. The mount should be located well away from or above any obstructions that can reduce sun exposure, especially during the winter months when the sun is weakest. Because of price, strength and weight, aluminum rails are normally used to fabricate the mount. All hardware should be stainless steel where possible to prevent corrosion.
Cables should be properly sized for the system power and distance between the panels, charge controller and batteries. Cables that are warm to the touch during operation indicate the cables are too small and energy is being wasted as heat. All cables should be protected by fuses or disconnects to reduce the possibility of fire due to short circuits. All cables carrying higher voltages should be protected in conduit. Exposed metal parts should be grounded. Safety features like properly sized wiring, disconnects, fusing, conduits and grounding are often omitted in cheaper systems.
We recommend you don't skimp on the inverter and charge controller, regardless of the overall size of your system. If you start out with good electronics, you or your customer can expand an initially well-designed system simply by adding panels and batteries rather than having to also change out the electronics. We also recommend you avoid off-brand components. Their higher failure rate is not worth the initial savings up front.
Batteries are a matter of personal choice and budget but do keep in mind that standard lead-acid batteries require regular monthly maintenance to keep them healthy. Batteries tend to be the weakest part of any solar system and can have a shortened life due to neglect. Also, don't make the common mistake of simply adding more batteries in an attempt to compensate for a too small solar system. This will only work if you are prepared to run a generator frequently to keep the batteries full, since your panels will no longer be able to supply the greater power required by more batteries to keep them full. After a few months, a system overloaded by too many batteries will begin to fail as the batteries become weaker due to undercharging.
The proper size of a solar system depends on the level of comfort you desire and, of course, your budget. An entry-level system would consist of around 680 watts of panels, providing about 3.3 Kwh of solar output per day. This is enough power to keep an average sized refrigerator running, and provide enough power for energy efficient lighting and small appliances. We normally won't sell systems smaller than this because customers often become dissatisfied with them and end up expanding the system.
Anything with a motor, like pumps, dishwashers, refrigerators, freezers, washing machines, dryers or air conditioners, places greater demands on a system. Normally, solar electrical systems designed to handle such larger loads fall in the range of betWen 1,800 to 3,600 watts.
Another factor is the system's capacity to support your energy needs when there is no sun; at night, on cloudy days, or during storms which may last for three or four days. Normally, this is accomplished by a battery bank and/or a back up gas or propane generator. However, as mentioned earlier, the battery bank must be sized according to the amount of panels you have. You cannot support a huge bank of batteries with a few panels unless you are willing to run a generator every few days to maintain the batteries at full charge.
The average American home uses roughly 800 kilowatt hours (Kwh) of electricity per month, or about 26 Kwh per day. But actual usage can vary enormously depending on where you live and what your own personal living habits are. Most people throughout the world live on far less electricity than that, and solar living demands it. Energy-efficient lighting and good energy conservation habits are keys to successful off-grid living here in Mexico.
Even in areas where municipal electricity is available, a solar electrical system is a wise investment. The municipal electrical supply in Mexico can be unpredictable, with regular and frequent outages, brownouts and surges a fact of life in Mexico. In the event of a severe storm or hurricane, municipal electricity can be knocked out for days or Weks before repair crews can reach damaged areas and restore power. Also, municipal electricity in Mexico is expensive. Especially for important appliances like pumps, refrigerators, telephones and computers, a solar electrical system can help offset a significant part of your monthly electrical costs, and help to ensure you have continuous, uninterrupted power available when others do not.
Please note that the following example systems are presented for rough budgeting purposes only, subject to revision based on current market pricing at the time of issuing a proposal. The prices shown are estimates not quotes, and based on labor and materials costs as of July 2008. Pricing for solar panels and equipment is subject to frequent changes, and a project will only be quoted on current market pricing as of the actual date of our proposal.
To provide some additional basis for cost comparison, over 90% of the cost of a solar electrical system is in the equipment, with around 65% in the panels. There are some ways to cut system costs by using cheaper charge controllers or modified sine-wave inverters. We normally don't sell these because they are generally less efficient and cause more problems. Please note these prices are estimates only and include normal installation. Please add 10% to all pricing for Mexican IVA. Actual contract values can and will differ.
640 Watt System (appx. 3.0 Kwh per day, or 90 Kwh per month) Sufficient to run a medium refrigerator, and the most basic electrical needs. - $13,000
4 - 160 watt panels
1 - Outback MPPT Charge Controller
1 – 3,000 watt/120 volt Outback true sine wave inverter with Outback Mate meter
8 - FLA Deep cycle solar batteries1,020 Watt System (appx. 5 Kwh per day, or 150 Kwh per month) - $15,000
6 - 180 watt panels
1 - MPPT Charge Controller
1 – 3,000 watt/120 volt Outback true sine wave inverter with Outback Mate meter
8 - FLA Deep cycle solar batteries1,440 Watt System (appx. 6.7 Kwh per day, or 200 Kwh per month) - $17,000
8 - 180 watt panels
1 - MPPT Charge Controller
1 – 3,000 watt/120 volt Outback true sine wave inverter with Outback Mate meter
8 - L-16 High-capacity FLA Deep cycle solar batteries Full metering, disconnects, grounding and fusing.
2,160 Watt System (appx. 8.5 Kwh per day, or 250 Kwh per month) - $25,000
12 - 180 watt panels
1 - Xantrex MPPT Charge Controller
1 – 4,500 watt/240 volt Xantrex true sine wave grid-tie capable inverter with meter
16 - L-16 High-capacity FLA Deep cycle solar batteries2,880 Watt System (appx. 13.5 Kwh per day, or 400 Kwh per month) - $29,000
16 - 180 watt panels
1 Xantrex MPPT Charge Controller
1 – 4,500 watt/240 volt Xantrrex true sine wave grid-tie capable inverter with meter
16 - L-16 High-capacity FLA Deep cycle solar batteries3,600 Watt/ System (appx. 17 Kwh per day, or 500 Kwh per month) - $38,000
20 - 180 watt panels
1 Xantrex MPPT Charge Controller
1 – 6,000 watt/240 volt Xantrrex true sine wave grid-tie capable inverter with meter
24 - L-16 High-capacity FLA Deep cycle solar batteries4,000 Watt/ System (appx. 20 Kwh per day, or 600 Kwh per month) - $41,000
24 - 170 watt panels
1 Xantrex MPPT Charge Controller
1 – 6,000 watt/240 volt Xantrrex true sine wave grid-tie capable inverter with meter
24 - L-16 High-capacity FLA Deep cycle solar batteries
Also, please note that the above prices assume the panels will be placed on a standard roof mount on a flat roof with ample space available to permit unobstructed sunlight during daylight hours. Raised roof mounts, or specially constructed mounts for locations with difficult installation requirements or limited space will be bid at additional cost. The inside equipment will be located within 30' of the panels, and connected to a single AC load center located within 30' of the equipment, and with the load center and access conduits provided by others. Trenching and conduit will be bid at additional cost. Battery compartments are not included and will be bid at additional cost.
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