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Introduction To Remote Power Systems (continued)
Deep Well Pumps
Deep well pumps can be a real problem for solar systems. Not only do most deep well pumps use a lot of electricity, they also have an even larger need for
electricity when they first start. The latter is called the electrical surge. Some inverters, especially the newer true sign wave inverters, are not able to handle the large surge of some pumps. Also, most pump
installers install 230 volt AC pumps so that smaller wires can be used. Most inverters are 115 volts!
 Generally speaking the deep well water pumps which are most compatible with solar systems
are high efficiency DC pumps. DC water pumps are generally very efficient and they don't have to draw electricity through an inverter. Thus less electricity is lost due to the inefficiency of the
inverter, and electricity is supplied directly to the pump from solar modules or the batteries. This means that a smaller inverter can be used and that if an inverter ever fails, then
the water pump will still run off of the batteries,  assuming the batteries are being charged by solar modules.
AC deep well pumps can also be used, especially if they are 115 volts and 1 HP or less (Note: Three wire
AC pumps plus ground require less electrical surge than two wire plus ground.) Larger, even 230 volt, AC pumps can be used with solar systems, however, a step
up transformer or two inverters will be required, or water can be pumped into a cistern manually once a week, or so, using a generator. A DC pump can then be used to pressurize. (Note: Avoid AC deep well pumps which
have no control above ground. When the control goes bad the pump will have to be pulled.)
Things To Consider When Selecting A Gasoline, Propane or Diesel Driven Electric Generator
- Sizing: derate 4% for every 1,000 ft above 500 ft in altitude. The larger
the generator the less time it will be on. Size an air cooled generator so that it does not run for more than roughly four hours at a time. Liquid
cooled generators can run for days without stopping at partial load, but they should only be run for a few hours continuously at full load. Size your
generator large enough to simultaneously charge your batteries and run your loads.
- Quality\longevity: For example, water cooled generators usually last 2 to 3 times as long as air cooled, 1800 RPM generators will last much
longer than 3600 RPM generators.
- Auto start
- Fuel Supply: You must have a large (usually propane or diesel) tank in order for your generator to operate automatically.
- Quality of the electricity produced: Does the generator produce electricity that is exactly 60 cycles?
- Noise level
- Fuel consumption
- Availability of a dealer who will repair your unit.
- Pollution.
An Example of the Maintenance Required on One of the Highest Quality Generators on the Market
- Kohler 10 KW Generator needs to have the oil and oil filter changed, water checked, etc. every 50 to 75 hours of run time. If the generator
runs six hours per day on average, that means changing the oil, oil filter, etc. every 1 to 2 weeks. If a generator runs three hours per day on average, then the maintenance is every 23 weeks.
- Major repairs are likely to be required on this excellent quality Kohler water cooled generator every 4,000 5,000 hours assuming the unit is
well maintained. and, of course, depending on how many hours a day the unit runs. If the generator runs four hours per day on average, and if the unit is well maintained. then major work would need to be done on
the unit approximately every three years. (This is not guaranteed, this is just a rough average based on talking with a Kohler Service Manager.) If
this generator is not well maintained, then it could need major work in less than six months.
- Most generators are air cooled and include far less quality than the above generator. So most generators will require repairing much sooner
than the above generator.
National Electrical Code
- Use only listed equipment and materials (when available) and pull a permit. Many solar system components on the market are still not listed.
- If you have questions, talk to Solar Wind Works or your inspector prior to purchasing and installing equipment so as to avoid problems later.
- The primary reason for the electrical code and inspectors is safety. Purchasing and installing a solar electric system which meets code has
the added advantage of making it easier to get insurance with some insurance companies, and of selling the house later.
- Eliminate three wire circuits from any house using a solar electric system, whenever possible.
Other Thoughts
The first step in sizing a system, whether it is a solar system or a generator
only system, is to fill out a load sheet. If you need a load sheet contact us and we will provide you with one. Once you have filled out the load sheet, mail, fax, or email it to Solar Wind Works and we will assist you with the design of your system.
We sell all of the components of solar electric systems, and also electric
generators, high efficiency and propane refrigerators, freezers, high efficiency light bulbs, and many related products. We can provide prices on specific items.
We keep a record of all solar electric purchases by customer. So if later you want to add to your system, we have a record of what already exists. We are
then better able to recommend additional items.
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