Technical topics

Common Myths Associated With Solar String Inverters
Solar string inverters have enjoyed a solid track record over the years. For their unmatched reliability, ease of installation and unparalleled efficiency, they are well suited for most all residential and even small commercial applications under energy incentives. A solar inverter converts the DC current produced by solar panels into AC current, which is then routed to power an array of household electronic devices or to an electrical grid. The range of applications for solar string inverters is virtually unlimited. However, there are a few tips that you must follow to ensure maximum performance from your solar string inverter system.
Know your DC input voltage. You must be able to determine your maximum voltage requirements before you set up your solar string inverter. This will help you configure your inverter with the highest peak efficiency. Note that peak efficiency is determined by multiplying the input voltage by the total DC input to the device. Peak efficiency is typically greater than unity for most solar cell applications.
Ensure proper placement of solar panels and mounting locations. It is important to note that solar panels will only operate at their maximum output in a narrow path. Pathways longer than about two inches will minimize the benefits of your solar pv system. Your solar string inverter needs to be mounted in areas with minimal mismatch losses in order to maximize energy production.
Mismatch losses may result from thermal expansion and contraction due to shading from structures around the solar panels. Panels need to be placed in areas where there is adequate exposure to direct sunlight to maintain peak efficiency. If these structures obstruct the sun's rays, the inverter will experience a lower than ideal performance. As an example, if your solar panel array experiences thermal expansion in areas where it receives little or no sunlight, it will not be able to produce high enough outputs to meet your electrical demands. The same thing holds true if the solar panels are located too closely to the structure of the building you are housing them in.
It is important to note that high efficiency solar string inverters do require more maintenance than traditional ones. They require periodic battery charging and occasionally being replaced with new batteries. This process does not have to take place on a regular basis, but when it does it should be performed on a regular schedule to ensure optimal performance. Your battery bank should also be drained or replaced at least once every year. Again, the frequency of your drain or replacement should match your power control plan. Failure to do so can result in excessive damage to your battery system and reduced overall efficiency.
Mismatch losses are one of the most common reasons why solar pv systems fail to achieve their intended efficiencies. These losses can come in many forms. For example, the inverter may need to be operated at a lower amp rating in order to prevent the amp-hours required to power your electrical needs being exceeded. If there are any losses noted during a testing period, this will need to be documented in your records.
It is imperative to check the connection of your solar power inverter to the properly grounded power line. This is usually done with a Ground Fault Circuit Interrupter (GFCI) connection. If your solar string inverters does not have this connection then it is very likely that it has either a loose wire or a connection that is poorly aligned. This will result in a loss of solar radiation.
Some solar pv systems have been known to experience a loss of power because of temperature changes. Unfortunately, most residential solar systems do not come designed with temperature sensitivity as a built in feature. It is very important to know and understand this potential issue. One way to test for temperature sensitivity is to place the solar string inverter in direct sunlight for a period of time.