Solar power inverters change DC power generated by solar panels into utility-grade AC power that can be used in your home. Solar hybrid inverters sit between the solar power system and, home appliances and utility grid. They can supply excess electricity from your solar panels to grid network and also charge batteries from grid network when the sun is low. To connect to the grid, the power needs to be in alternating current and solar inverter does the job.
DC current is Direct Current, and AC is Alternating Current. DC current is used for battery operated devices. AC current is the standard for everything that you plug into the wall. DC current is unidirectional and in the same direction in a circuit, while AC current is in a “back and forth” direction in a circuit. DC current cannot be used in certain types of equipment, such as AC adapters and cars, because it does not flow in both directions. To use DC current in equipment that requires AC current, such as an AC adapter or car, we must convert it into AC current using an inverter. Read why do solar cells need an inverter here. Use inverter size calculator here.
What Is A Solar Inverter
A solar power inverter also known as PV inverter is a hybrid inverter that has the capability to convert 12/24v DC electricity in 120/240v AC electricity and vice-versa to supply power to off-grid electric networks and can feed power into grid supply.
A solar inverter has a built-in charge controller, which is used to provide a steady supply to the battery to charge and then receives the 12/24v dc power from the battery and converts that into 120/240v at 60/50Hz for regular power utilization for home appliances. See details here.
It also has the ability to charge batteries from 120/240v AC by rectifying them into 12/24v dc. It is a compact smart electric machine that works between the solar panel, battery, electric load, and grid supply by keeping every current form and voltages according to their need. You can feed your extra produced electricity to the utility grid power supply companies using a solar grid tie inverter.
It’s worth noting, approval from the utility grid authorities is required for selling electricity to them. These are perfect off grid inverters for solar energy system. Read my guide on best 3000 watt inverters here.
Solar Inverter Cost
A solar inverter solves a lot of your problems by converting 12/24v dc supply from the solar panel into 120/24v AC at 60/50Hz frequency, but that comes with a serious cost. It can be anything between $1000-3000. As modern solar inverters are smart machines that decide many things at their own pre-set values and uses controllers, converters, transformers, and filters in the process, that adds up to their price.
Solar inverters offer many benefits of hybrid input mode, no running cost, pure sine wave frequency, better efficiency, longer life, better voltage regulation at input and output over standard inverter that is why it is way more expensive than a standard inverter. Compare prices here.
How Does A Solar Inverter Work
The solar inverter takes 12/24v dc supply from the solar panel, which can go a bit up or down according to the sunlight density. It has a built-in charge controller that changes the input dc value into pre-set values by using amplifiers and supplies a steady 12/24v dc supply to batteries and also can charge batteries from 120/240v AC grid supply by converting it into 12v dc.
Then receives power from the solar battery of energy storage system, and converts 12/24v dc into 12/24v AC through electronic switches made by using different transistor connection techniques and finally that 12/24v AC is transformed into 120/240v AC at 60/50Hz by using step-up transformers. Here filters are used to remove unwanted frequencies from the supply line.
Through a solar grid tie inverter, you can sell power produced from your solar panel to grid AC power supply. In such conditions, your solar inverter does all the job by converting 12/24v DC electricity into 120/240v AC electricity matches the frequency at 60/50Hz, waveform phase at pure sine waves, and angle 1 degree higher than the grid supply. Then supplies to utility grid. It keeps voltage a little above the grid supply as potential differences let the power flow from the inverter to the grid.
In case of black-out, the solar smart inverters stop supplying power to the grid as they have a maximum power point tracking mechanism to continuously evaluate the voltage difference and lookout for maximum power limit. Read my guide on how power inverters work here.
Types of Solar Power Inverters
- Solar String Inverter
- Central Solar Inverter
- Solar Micro-Inverter
These three types of inverters are based on their network topology, conversion ability, and the size of load they can take on.
Solar String Inverter
In a string inverter, many solar panels are connected with a string and placed in a row, there could be multiple rows, but at the end, all of these strings are connected to the inverter. This is the classic design of solar inverter, used since its first commercial use.
It’s best for a load below 1MW, for a typical house or small commercial load. String inverters can be installed on any external wall of your property, which helps you monitor the input/output voltage regulation and solar battery charging status.
String inverter is more in-demand in the market because our domestic or single commercial loads are below 1MW and above 3KW, which are limitations for other types of inverters. The primary advantage they offer is they are more affordable for domestic and single commercial load than other types of the inverter. Read my guide on best 1000 watt inverter here.
Central Solar Inverter
A central inverter is used for a load above 1MW. Instead of multiple string input, all strings are connected through a common box that drives 12/24v dc supply power from PV system to the central inverter.
Central inverters are installed at larger solar installation units, and where consistent power is required. Central inverters are more suitable for Solar farms and large collective commercial units than string inverters. It has a better response to change in input power as the light density changes because of its larger conversion unit.
Read my guide on best 2000 watt inverter here.
Solar micro inverter is small-size inverter that are installed separately at each panel and convert the 12/24v dc supply to 120/240v AC right after its production. Some solar panel manufacturers already install them at each solar panel to make solar installation easier for you.
Solar micro-inverters can be used for very small consumption units up to 3-5KW as for higher range these would be very pricey. Such inverters would do well for solar water pumps and other single/small load consumption.
Solar Panel Micro Inverter Vs. Central Inverter Vs. String Inverter
|Feature||String Inverter||Central Inverter||Micro Inverter|
|Power Conversion Capability||1 kW to 1 MW||Above 1 MW||100 watts to 1.4 kW|
|Cost to conversion capacity (Feasibility)||Moderate||Moderate||High|
|Usability||Best for 3kW to 20kW||Best for 1-2 MW||Best for 200-800 watts|
|Installation cost||High||Moderate||Very High|
|Preferred load type||Domestic or single commercial unit||. Solar Farms or large commercial projects||Single high watt load or small overall load, off grid setup|
|Market Availability||Readily Available||Hard to find||Readily Available|
What Does A Solar Inverter Do
- Converts Solar Energy Into AC Electricity
- Enables Selling Extra Electricity To Utility Grid
- Protects Environment By Reducing Carbon Footprint
- Saves Money On Electricity Bills
- Efficient and Almost Zero Operating Cost
- Enables True Off Grid Living
Converts Solar Energy Into AC Electricity
Direct DC power output from solar panels can’t be utilized by our many home appliances. So, the solar inverter makes it useful by converting 12/24v dc supply by the solar panel into 120/240v AC, which is consumed by electric appliances.
Enables Selling Extra Electricity To Utility Grid
Grid tie solar inverter allows you to sell excess electricity produced from your solar PV system back to your utility grid network, and power companies will pay you back for that! All you need to do is install your solar system with a grid tie inverter, which feeds power into the grid supply after matching voltage level, frequency, waveform, and phase angle.
Protects Environment By Reducing Carbon Footprint
Hybrid inverter plays a very crucial role in solar power system, which reduces the human carbon footprints and produces clean and green energy without emitting any greenhouse gas.
Saves Money On Electricity Bills
As with a solar power system, you don’t have to pay any bills for your power consumption that helps in savings and a good earning to expense ratio for a small business unit.
Efficient and Almost Zero Operating Cost
Smart inverters are very efficient power optimizer that can be efficient anywhere between 85-98%. So, with this much efficiency, a solar inverter consumes very little power in the process of inverting and transforming power. The energy consumed for the conversion is also generated from solar panels, which is free of cost.
Enables True Off Grid Living
The grid supply faces many disturbances in voltage due to the reactive power in distribution and transmission line and doesn’t give a steady 120/240v AC supply but a bit higher/lower. The Solar inverter provides your electric appliance a steady 120/240v AC power output by perfect transformation and filtering process.
Cons Of Solar Inverters
- Sunlight Dependent
- High Repair Cost
- High Space Requirement
As solar panels convert solar energy into 12/24v dc electric energy, which is later converted by an inverter into 120/240v AC power. That defines the solar inverter’s dependence on sun light. If there is no or considerably low light for a time, a solar inverter would be an electric appliance of no use when the storage battery is down.
High Repair Cost
A solar inverter is a quality electric machine having a life of up to 12 years, but if due to any uncertain and unwanted accident, if its internal converting circuitry gets damaged, then repairing cost is very high. Second, it will never gain the same efficiency and quality after one is exposed to serious damage.
High Space Requirement
A solar inverter depends upon a solar power system as it receives input from solar panel and solar battery. These solar panels require huge space for installation that you might have to give them extra space on your rooftop.
Standard Power Inverters Vs. Solar Inverters
|Feature||Standard Inverter||Solar Inverter|
|Charge Controller||Doesn’t Have||Built in|
|Output||Voltage Fluctuations of +5/-5%||Steady 120/240v AC output|
|Hybrid Mode||Doesn’t have||Charges the battery from grid supply too|
|Frequency||Square wave, Sine wave and Modified sine wave||Pure Sign wave|
|Input||Supply Grid only||Solar power & Grid both|
|Operating Cost||High as grid supply is expensive||Free of cost as solar power is free|
The regular power inverter does not have a built-in charge controller. So, it doesn’t get steady 12v dc input when the battery is low.
As the solar inverter gets a steady 12v dc supply from the battery until it is completely drained out, it has a better-regulated output voltage at 120/240v at 60/50Hz frequency.
Which is more efficient? Monocrystalline Vs Polycrystalline Solar Panels or this new kid in the block?
Standard inverters only charge from the direct 120/240v AC supply, but a solar inverter has dual input options, and you can charge your battery from solar power in the day and grid supply at night times.
There are standard inverters in the market claiming pure sine wave frequency, but as they don’t have much-regulated input supply, their sine wave is not 100% pure and therefore has low efficiency of 80-90% compared to 85-98% of solar inverters which has pure sine wave.
A standard inverter converts the grid 120/240v AC supply into 12/24v dc at the cost of consuming electricity from grid supply, which is expensive. A solar inverter converts power from 12/24v dc to 120/240v AC through solar power, which is free of cost.
A solar inverter has a longer life span as it receives much-regulated input voltage compared to the standard inverter and has extra protection schemes for current, load, and voltage surges.
Solar Inverters FAQ
A solar inverter is must have if you want to install a solar power system as it is specifically designed for solar system power conversion from 12/24v dc to 120/240v AC. Always buy a solar inverter that has 200% power conversion capability to your present load because you may increase the load in the future, and the inverter is most efficient 98% at load between 30-40%.