Discussions about solar energy systems tend to focus on the solar modules themselves – the most visible component in the system — and often, neglect the other important piece of hardware: the inverter.
Some would argue that the choice of inverter is actually a more important decision than the solar module because the solar module plays a somewhat “passive” role in gathering the sunlight while the inverter is more actively managing it, while keeping track of (“data logging”) how much power is being produced.
There are two types of inverters: the “tried and true” central inverter (also called the string inverter) and the newer technology called the micro-inverter. There is an ongoing debate as to which one is better.
Central inverters have been in use for more than 40 years. Micro-inverters are still a fairly new technology, only in commercial usage for the last 10 years. Central inverters are typically mounted on the side of the home near the main electrical panel, while micro-inverters are mounted on the back of individual solar panels on the roof.
The central inverter requires that panels grouped into “strings” or circuits. If one panel in as string has shade that causes it to lose production, all of the panels in that string are also affected. However, with a micro-inverter system shade only affects the single module being shaded; the neighboring, unshaded panels still produce at full power. Each micro-inverter essentially manages its own solar module independently rather than in groups.
Similarly, the central inverter powers the entire solar energy system so if the inverter fails, the entire system stops working until the inverter is repaired or replaced. If a single micro-inverter fails, the rest of the system is still working properly and producing power.
It should also be mentioned that a central string inverter usually weighs over 100 lbs and must be shipped via truckline (which may take up to 1 week) and require at least 2 workers to replace it. A typical micro-inverter weighs less than 5 lbs and can be shipped overnight and installed the next day by a single worker.
The most common question about inverters concerns the warranty. Central inverters have a standard 10-year warranty and are typically a little less in cost depending on the size of the system; however, an extended warranty can usually be purchased. Micro-inverters come with a 25-year warranty standard.
Finally, not all brands of solar panels are compatible with micro-inverters, due to their unique technology. It is importnat to check with an experienced solar installation company who can recommend the best system for your needs, both in terms of equipment and financing.
Stellar Solar carries multiple brands of central sting inverters as well as microinverters and has been in business since 1998, supporting both commercial and residential solar energy system installation, so we can recommend the right system at the right price with the right financing for homes and businesses throughout San Diego.