The decision to install solar is a simple one. It will save you money so you should do it. Solar panels require an inverter to convert the DC power that they produce to AC power that your appliances need. So you know an inverter (or inverters) needs to be part of your solar package, but navigating the options on what type of inverter technology is right for you can be little more complex.
The basic options are microinverters, string inverters, string inverters that require optimizers and battery-based inverters.
Microinverters are installed at the solar panels. They will mount to the solar panel frame or the racking depending on what racking you are using. There is typically one microinverter for every one or two solar panels. The most popular brand for microinverters is Enphase who pioneered the concept of microinverters many years ago.
String inverters are very different than microinverters. They are installed separately from the solar panels and one string inverter can handle many solar panels. How many solar panels can go on a string inverter depends on the size of a the string inverter and the wattage of the solar panels. The residential string inverters usually max out at about forty solar panels while a larger commercial inverter could handle hundreds of solar panels. Inverters designed for utility scale solar farms can even handle thousands of solar panels but that is probably a little bigger than you are looking for here.
The name “string inverter” comes from the fact that the solar panels are wired together in series strings. Some string inverters require DC optimizers be installed at the solar panels. One or two solar panels connect to each optimizer and then the optimizers are connected together in a string.
It used to be that only SolarEdge inverters needed to have optimizers in installed, but the new NEC 2017 requirements for rapid shutdown has changed the rules for all string inverters. If the system is installed on a building, there need to be rapid shutdown devices that can de-energize the system at the module level. These may not be as complex as the SolarEdge optimizers which do maximum power point tracking for each solar panel but at the very list they have to be a switch that can turn off the DC power for each solar panel.
Finally, there are the battery-based inverters which get their power input from batteries instead of solar panels. If you are installing a battery-based inverter as part of your solar power system, you would need to install charge controllers to manage the power from the solar panels going into the batteries and then the battery-based inverter would convert the battery power into usable AC power.
So, now you know what the technologies are and the question still remains, which one is right for you? If you want to simplify your installation, Enphase microinverters are a good choice. These are easily mounted under the solar panels and then you are dealing with AC power instead of high voltage DC power from the solar array to your main service panel.
If you have some solar panels that will be shaded during the day or solar panels facing a few different directions, it would be best to go with microinverters or a system that includes DC optimizers that have maximum power point tracking for each solar panel.
Very large systems or systems that are not going to be on a building (like a ground mounted system that feeds a pedestal main service panel) will be less expensive if you use regular string inverters.
Battery-based inverters would be the best option if you are off-grid. If you are on the grid but want battery back-up power, you can use the battery-based inverter or any of the other inverter options if you use the right battery equipment. There is the new Enphase Ensemble battery technology that will work with any Enphase IQ microinverters to provide power during a power outage. SolarEdge has a battery solution using their StoreEdge inverter with LG Chem batteries. Other string inverters can be AC coupled to battery-based inverters like the Outback Radian.
For help choosing which technology will be best for your solar installation, contact the experts at GoGreenSolar.com.