The main difference between micro-inverters and string (or central) inverters is where and when they convert DC energy to AC energy. Picking the right can increase your solar system's performance and maximize your savings.
In this article, we’ll cover the the basics of string inverters and micro-inverters to give you a sense of which type is best for your solar system. The basic function of an inverter is to change the Direct Current (DC) power generated by the solar panels to Alternating Current (AC) that can be used to power your home. The type of inverter you choose affects the total cost of the system, efficiency and, monitoring ability of your system.
Micro-inverters are mounted directly on each solar panel and convert the electrical current at the source of creation, whereas a string inverter is mounted on your house and converts the electrical currents from all the solar panels in one central location.
String inverters are the simplest and lowest cost option. When using a string inverter, the solar panels are wired together in a series and connected by a single string to a large inverter installed on your home next to your utility meter. A typical string inverter is around 50 pounds and around 30 inches tall, 20 inches wide, and 8 inches deep — roughly the size of an acoustic guitar (without the neck or the guy at the bonfire playing it).
These types of inverters are best for solar systems that receive full sun and have panels mounted in one large grouping. However, string inverters convert the total energy based on the lowest performing panel so it’s important that all panels are behaving at similar levels to maintain optimum output.
With string inverters, the lowest performing panel dictates the production of the entire system. So if one panel has a branch shading it by 30%, you will only receive 70% of your total system’s possible production. However, this problem can be solved with optimizers.
Compared to string inverters, MICRO-INVERTORS are much smaller and they are mounted on the back of each individual solar panel.
Micro-inverters convert each panel’s direct current to alternating current at the source of creation. Each micro-inverter works independently, so if one panel’s output suffers from shading it won’t affect the other panels. Micro-inverters tend to cost a bit more but are a crucial part of getting the most energy out of systems with unique specifications.
Additionally, micro inverters provide the option for additional panels to be added in the future should your needs increase. Supplementary panels are installed and connected with their own micro inverters. In contrast, if you have a traditional string inverter, enlarging your system means adding a second inverter. This adds significant expenses and may make adding panels in the future more difficult.
Finally, there are advantages to micro-inverters when it comes to monitoring your solar system.
Solar system monitoring software uses data collected from the inverter to tell you how your system is performing. While string inverters provide information about your comprehensive solar system production, micro-inverters tell you how each individual panel is performing. This data can be useful in troubleshooting for maintenance needs.
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