With the increased interest in renewable energy sources across the globe, inverter technology has been steadily evolving over the past several decades to better enable homeowners to reap maximum power from their PV systems. Both string inverters and micro-inverters do this job for you as a solar homeowner, but go about the process in different ways. Continuing from the previous weeks about basic introduction and troubleshooting of inverters, this week we are going to discuss about the pros and cons of different string inverters and micro-inverters.

A string inverter is also known as central inverter is a typically standalone inverter that is typically installed close to main service panel and electricity meter. There is typically only one single inverter, or possibly two string inverters on each residential solar installation; it really depends on the overall solar power system size.

• Easy troubleshooting;
• Lowest possible cost;
• Lower probability of wiring mishap;
• Comparatively easy maintenance;
• Great performance without shading.

• Overall production decreases if a panel is damaged or a portion of panel is shaded;
• Not able to monitor each panel individually;
• Difficult for system expansion;
• Comparatively shorter lifespan, where these are warranted to last between 15~20 years.

Micro-inverters perform the same basic function as string inverters, except they are installed underneath each solar panel on your roof. Each of these micro-inverters is about the size of an internet router. The big difference between micro-inverters and string inverters is that a solar panel installation with micro-inverters will typically have the same number of micro-inverters as there are solar panels.

• Doesn't affect the performance by the nearby shadow;
• Individual monitoring possible;
• System expansion easier and cheaper compare to install second central inverter;
• Good performance for rooftops where solar panels may face different directions;
• Comparatively greater lifespan, with usually 25 years of warranties are provided by different vendors.

• Higher initial cost and comparatively higher price than string inverters;
• Maintenance is little bit complex as it's installed in the solar panel;
• In case of rooftop installation, each inverters are installed in the panels so lots of expensive metals are installed in the rooftop which might cause a hazard or an accident during lighting or storm.

In the event of isolation fault, the inverter usually stop working or continue to work at the minimum "required" isolation level. As a result, in each of the cases the inverter doesn't work in full efficiency and capacity. To avoid this problem, it is mandatory to ensure DC cables are of highest quality and installed correctly. Also, by selecting the inverter with proper level of IP protection can give safety on this issue.

Ultimately, the best inverter for any purpose is basically depends on the roof shape, size, nearby trees, how much energy is required and the budget.