Basics Equipment
Equipment
Inverters
Inverters change the direct current (DC) from solar arrays or batteries to the alternating current (AC) used by the utility company and most household appliances. The two basic types of inverters are grid-connected and stand-alone.
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Charge Controllers
Charge controllers control the charging of batteries. They keep the battery from being over charged. Like inverters, most charge controllers have maximum peak power tracking (MPPT) which keeps the solar array operating at the maximum power point. The array voltage normally has to be higher than the battery bank voltage for charge controllers to work.
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Batteries
Most batteries used in solar systems are lead-acid. This is the same kind of battery used to start cars, with one important difference. Car batteries are designed to provide a high current for a short time. They are called starting batteries. Lead-acid batteries used in solar systems are designed to provide a smaller current for a longer time. They are called deep-discharge or deep-cycle batteries. Deep-discharge batteries can discharge 80% of their capacity while starting batteries can only discharge 20% of their capacity. Deep-discharge batteries provide about 4 times the energy of the same size starting battery.
Water Pumps
The two basic types of water pumps are submersible and non-submersible.
Submersible pumps are meant to be installed under the surface of the water. The motors and electrical wires are waterproof. Submersible pumps are usually used in wells. They can be designed to provide a high pressure, called head, or a medium head. They can be a positive displacement type, a good choice for solar applications, or centrifugal type that pump a variable amount of water depending on pressure.
Non-submersible pumps are meant to be used above the surface of the water and must be kept dry. They are used to pump surface water. They can be high volume and low head or medium volume and medium head.
Read more about water pumps
Trackers
Trackers are mechanical devices that move to follow the sun. They can move in two axes or one axis. Two-axis trackers are more accurate but one-axis trackers can provide most of the benefit of two-axis trackers with less cost and complexity. Because the tracker points the modules towards the sun, more energy is produced, up to 30% more energy depending on the local climate. Bright, clear, sunny locations, such as the south-west United States, provide more benefit than overcast areas, such as hazy seaside locations.