The Ins and Outs of a Solar Inverter
When sunlight hits solar panels, they create a flow of DC electricity. To power household appliances and feed excess energy into the grid, this needs to be converted to AC electricity.
Inverters manage this task, as well as monitoring and protecting your system. They are also an essential component in a solar-plus-battery backup system that can operate independently from the grid.
Voltage Regulator
The voltage regulator regulates the energy flowing from the solar panel to the battery. It helps to protect the batteries from overuse, prevents overcharging and draining, and provides a consistent power supply. It also prevents damage to the load equipment from high voltage fluctuations. It works by acting as a blocking diode when the solar panel output exceeds the batteries’ safe charging value.
It is important to mount your solar voltage regulator in a safe location. It should not be exposed to direct sunlight or rain, and it should be easily accessible for maintenance and troubleshooting. It is also best to use heavy-duty cables, and to install a fuse or circuit breaker to protect the regulator from overloads. It is also recommended to insulate the cables to avoid heat loss, and to label all connections so that they can be easily identified.
A simple 1 or 2 stage controls which relies on relays and shunt transistors to short or disconnect the solar panels when a set voltage is reached. These are dinosaurs and can be found in super cheap solar systems on the internet.
Modern MPPT solar charge controllers provide the highest daily production by tracking the optimum string voltage of your solar panels. These bidirectional voltage regulators Solar Inverter can detect undesirable mains variations and quickly react to them, establishing an immediate and quality energy supply.
Battery Charger
The battery charger is the heart of a solar energy storage system. It’s designed to charge the battery at a rate safe for its chemistry and prevent overcharging which can ruin it. Lithium batteries require a specific charging method that limits current and protects the cells.
A multimode inverter charger is a great choice for off-grid solar power systems or as part of a hybrid grid-tie system. It can be configured to provide AC or DC power and has a built-in 100 amp charger that uses a gas or diesel generator to recharge the battery bank in emergency situations.
When connected to the load output of a charge controller this inverter can draw up to 300W and is capable of handling startup surges like those found on appliances like blow dryers, microwaves, and refrigerators. It’s also compatible with electric vehicle (EV) charging stations, which makes it a popular choice for EV owners looking to harness the sun to help reduce their fuel costs.
It connects directly to 12 volt batteries via its terminal blocks and can be combined with a deep-cycle battery system for off-grid home, marine, RV and backup power applications. Keeping the inverter and charge controller as close to the batteries as possible reduces resistance and potential failure points like hot spots. These inverter-chargers often have built-in connections to the batteries and other components within the system, so fewer bus bars, wires, fuses and shunts are needed compared to a separate installation of an inverter and charge controller.
Power Optimizer
Power optimizers are module level power electronics (MLPE) designed to increase a solar energy system’s performance. Much like microinverters, they optimize each solar panel at the module level so that a single panel’s performance isn’t affected by shade or a north-facing roof, and they offer installers and homeowners real-time, panel-level monitoring.
They do this by bucking or boosting the DC output of individual solar panels to help them match the design input voltage of their centralized inverter. They can be paired with any inverter, but the best option is a smart, high efficiency centralized inverter.
A qualified solar professional will recommend the correct size inverter for a PV system with power optimizers, based on their proposed panel wattage and site conditions. A power optimizer can also be used with a battery to increase home energy storage capacity, which is a great way to maximize your solar investment.
As with the other devices in a PV system, power optimizers have their own operational and maintenance needs. They need to have a power source, and they’re almost constantly bucking or boosting their operating voltage throughout the day. This can cause them to draw on their built-in batteries, leading to a reduced lifetime and lower efficiency. Moreover, they require around 2.7 m of extra cabling per power optimizer, and this additional wiring can result in significant losses due to resistance and voltage drops.
Maximum Power Point Tracker (MPPT)
Maximum Power Point Tracker (MPPT) is a feature within your solar inverter that ensures your panels are delivering the maximum available power. It does this by varying the voltage and current that the PV modules deliver to the battery. Think of it as a car’s transmission that automatically changes the gears to match the load and speed, so your system can work efficiently.
MPPT solar charge controllers can deliver 10-30% more energy to your SOLAR DC FAN batteries than a standard charge controller under most conditions. They do this by constantly sweeping through your panel voltage range to find the best combination of voltage and current to generate the most power. This works well because solar panel irradiance is not constant – it is varying throughout the day and in different weather conditions.
The best MPPT solar charge controllers sweep the entire IV curve and look for the one spot where the total array power is maximized. This method of finding the MPP is called global MPPT and it is an important feature to look for when selecting an inverter.
Some inverters are not designed to perform global MPPT and only operate at a local maximum point. Aurora contacts manufacturers to confirm whether an inverter performs global MPPT before including it in a performance simulation. This is also a great reason to choose an inverter that has bypass diodes at the string level.