Every solar array has a solar inverter built in - this is the part of the system that converts the direct current (DC) power that the panels produce to an alternating current (AC) used in homes. There are two main types of inverters: microinverters and string inverters. Microinverters are connected to each panel in the array and are good for complex installations while string inverters connect several panels into one and are best for simple installations.
Microinverters
Microinverters are usually attached to each panel, although you can find models that can handle 2-4 panels as well. The conversion of power happens at the source of each panel, which provides some great benefits. If there is an issue with a panel producing power or if there is shade on a panel, then that issue will be isolated to that single panel. With string inverters, to contrast, if there is an issue with one panel, all panels hooked up to that string will be affected. Microinverters, therefore, are great for efficiency!
Micros are also popular because they meet the national electrical code and safety standards, whereas string inverters need to add DC optimizers or rapid shutdown devices to meet code.
Pros:
Meets code requirements
Easy to expand system
Can monitor the system more accurately - down to individual panels
Allows for complex designs
25-year life span
Individual performance doesn't affect other panels
Cons:
More difficult to repair than string inverters
More expensive
String Inverters
String inverters are installed by connecting multiple panels to a single string, which is ran back to a system that completes the job. Most simple home installations only require one string. Because of how these are connected, if there is an issue with one panel in the string, all panels will be affected. If that panel is shaded, for example, then all panels will perform as if they are shaded, too. These are great for simple installations where there is full sun to the array.
Pros:
Easy to repair
Lower cost
Simple system design
Cons:
Efficiency in shade or single-panel issues
Difficult to expand system
10-year lifespan
Additional equipment needed for rapid-shutdown requirements
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