Updated: Jul 6, 2020
A solar optimizer is a module that is often connected to a solar panel to optimize its output. They are a counterpart to micro-inverters and solar controllers. Read all about micro-inverters here and solar controllers here.
Their work in a solar system is to increase the system’s total energy output. They do this by constantly measuring the maximum power point tracking (MPPT) of each individual solar panel, adjusting the DC characteristics to maximize energy output and then relaying performance characteristics to a monitoring system for maintenance purposes.
How Optimizers Work
Power optimizers are essentially DC-DC converters. They work by taking the DC power from a solar panel at whatever voltage and current is optimal then converting it to a different voltage and current that best suits the inverter.
They do this using the MPPT. An MPPT, or maximum power point tracker is an electronic DC to DC converter that converts a certain DC from solar panels to the DC needed to charge batteries or to be converted to AC by the inverter. Their use is to extract maximum available power from the panels under certain conditions. In other words, they help increase the MPPT of solar panels.
Microinverters And Power Optimizers
Solar panels produce DC from the sunlight which is then converted to AC by an inverter. When a solar panel is fitted with a micro-inverter, it is then able to produce AC directly. In that case, they become 'AC solar panels' rather than DC solar panels. (Some solar panels come with a factory-installed micro-inverter. These types are referred to as 'AC solar panels'.)
These micro-inverters are designed to be installed one to each solar panel. This is in contrast to the single, standalone, common (string) inverter that is usually installed away from the panels themselves and connected with solar cables. Since micro-inverters are attached to every solar panel, each panel works independently from the rest of the solar array and the DC generated from the sunlight is converted to AC immediately on the roof.
Micro-inverters and power optimizers are counterparts. They are sometimes described interchangeably. They are classed as “Module-Level Power Electronics,” or MLPEs.
Similarities Between Microinverters and Power Optimizers
They are both installed at individual panels and they both monitor the performance of individual solar panels, rather than the entire solar panel system. Microinverters and power optimizers improve performance for solar panels on complicated roofs, or roofs that experience marginal shading during the day.
Also, they both come with 25 year warranties. But while they provide many of the same benefits in a solar system, the two technologies also have many functional differences.
Like microinverters, power optimizers are installed at each panel. However, instead of converting the DC to AC at the panel like micro-inverters, the optimizers “refines” the DC and sends it to a central inverter that finishes the conversion process. The “conditioning” process fixes the voltage of the DC energy so that the central inverter can more efficiently convert it to AC energy. Systems with power optimizers are more efficient than the standard string inverter option.
Microinverters are relatively costlier per total output. Though the difference in cost can be managed.
Both microinverters and power optimizers are compatible with battery storage. But because micro-inverters give out AC, they cannot be used with the common DC battery deep-cycle battery systems. They will require special types of AC batteries, which are far costlier. This makes them financially unattractive. Optimizers work with normal deep-cycle systems.
Solar Edge is the most reputable manufacturers of optimizers.
For all of its installations in Lagos and around Nigeria, SolarKobo replaces power optimizers with solar controllers. They are more durable and make for easy maintenance.