What Is a Solar Inverter?
A solar inverter is the heart of your solar power system, transforming DC electricity into AC for everyday use. It optimizes energy, monitors system productivity and communicates with the grid.
Inverters are also important components of solar-plus-battery storage systems that offer off-grid energy independence. The type of inverter you choose depends on shade patterns and your electricity needs.
Voltage Regulator
The voltage regulator is one of the most important parts of a solar power system. It is responsible for managing the current flow between the solar panels and the batteries. A good solar regulator will keep the battery charge at an optimal level. It will also prevent the battery from overcharging. A battery that is charged too much will degrade rapidly and can even explode. A voltage regulator is a necessary part of a stand alone solar system that uses a battery bank and a power inverter.
A solar regulator works by using a basic ‘rapid switch’ to modulate the charging of the battery. The switch opens and closes very rapidly (hundreds of times per second) to control the Solar Inverter current. This allows the solar panel to operate at its optimum operating voltage (Vmp). The regulator then converts the DC current to AC power. This AC power is then injected into the grid to be used by electrical appliances.
A solar regulator is a must for all off-grid systems with a battery bank. It can also be installed in grid connect systems with a power inverter. It is best to consult a specialist before deciding on whether a solar regulator is needed for a particular system. The best place to install a solar regulator is in an area that is protected from the elements and easily accessible for maintenance. It is recommended that the cables connecting the regulator to the solar panels and battery are heavy-duty and properly insulated to avoid heat loss.
Power Optimizer
Power optimizers are a solar power system solution that works in conjunction with your panels to help you get the most out of your solar energy setup. They do much of the same work as microinverters but in a more cost-effective way for homeowners looking to make the most out of their solar installation.
A Power Optimizer regulates the DC voltage from your solar panels and routes it to your inverter. Essentially, they work to negate shading effects that traditional string inverters struggle with. Power optimizers also enable you to monitor your panels on a panel-by-panel basis for more control and visibility.
One of the main drawbacks of using Power Optimizers is that they may shorten your inverter lifespan. Unlike solar panels, which have standard 25-year warranties, the inverter to which your power optimizers are tied has a warranty that only lasts 8 to 12 years. Because power optimizers route so much electricity to your inverter, they can cause the inverter to overheat and shut down prematurely.
Lastly, power optimizers do not always add as much energy yield as they claim to. In theory, this is because the bucking and boosting of modules’ operating voltages to match your inverter’s output reduces their efficiency. This can be especially true in the early morning and late afternoon when solar irradiation is at its lowest.
Maximum Power Point Tracker (MPPT)
Most solar homeowners hear about maximum power point tracking, or MPPT, a lot from their installers and designers. But what exactly is it? It’s a complex piece of technology that is vital to your solar energy system’s success.
MPPT varies the electrical operating point of your PV modules to extract maximum available solar power into your batteries as increased charge current. It is not a mechanical tracking system that physically moves the panels to point more directly at the sun, but a completely electronic system.
To do this, an MPPT controller tracks the current-voltage (IV) curve of the PV module to locate its optimal operating point. This is the SOLAR DC FAN point of peak power output under standard test conditions. The PV panel doesn’t dictate what the operating point will be; it can be anywhere on the IV curve. MPPT finds this point for the PV, and it is like a car’s transmission that varies the ratio between speed and torque based on driving conditions.
MPPT is very efficient at increasing the amount of energy that a solar system can harvest, and it can do this without increasing the voltage output to the battery. However, it does introduce some inefficiency due to energy conversion. Nevertheless, this does not significantly affect overall energy yield.
Battery Charger
When you connect your battery to the solar inverter, the charge controller automatically takes over. It regulates the voltage and current to prevent overcharging. This is incredibly important for the longevity of your batteries. Make sure that you always connect the battery to the charge controller before connecting it to the inverter.
If you have a lithium battery, you will need a battery charger that is designed specifically for it. It will charge the battery at a rate that matches its own self-discharge rate to help it stay fully charged.
Some inverters also provide backup power during grid outages or at night, and communicate with the utility grid to synchronize their frequency and voltage to match those of the utility. In addition, they can detect and diagnose faults that occur in your system.
If you are constructing your own system, it’s essential to understand how the different components work together. For example, you should always connect your battery and solar panel to the charge controller before connecting them to the inverter. This ensures that the voltage and current are regulated to prevent overcharging, which can damage the batteries. You can check the battery voltage with a voltmeter, which can be purchased at your local hardware store. They come in either analog or digital form and work by connecting the black and red ports of the battery to get a reading.