Solar Inverters -Off Grid, Hybrid and Grid Tie
The heart of your solar solution
Quality, well supported solar inverters in South Africa
Hybrid Solar Inverters Off Grid Solar Inverters Grid Tie Solar Inverters
Magneto 5 KW – 8kw Hybrid Single Phase
Basic Guide to Understanding Types of Solar Inverters - Which is best For Your Site
What size inverter should you get?
Types of Solar inverters
Grid tied inverter
Off grid inverter
Inverter with Batteries
South Africa’s most popular inverters for residential and SME’s
Also check Inverters for Home for more info
What does the inverter do – the simple explanation of an inverters function is to convert DC or Direct Current to AC Alternating Current.
Solar inverters are the brains of the plant controlling electrical feed from the panels and charging the batteries.
This guide will predominantly deal with solar inverters or inverters used in solar applications.
The main difference between a UPS, Backup inverter and solar inverter is that a solar inverter has a solar charge controller or MPPT. The MPPT controls and adjusts the input voltage to harvest the maximum amount of power from the solar array. MPPT or charge controls can be added to inverters that don’t have them built in. Some solar inverters can also be used as a backup system without PV panels and charging batteries from the grid. With this type of inverter as a backup you have the option of adding panels later.
Inverters AC output can be pure sine wave or modified sine wave
Pure sine wave vs Modified sine wave.
Pure sine wave inverters are usually more expensive then modified sine wave inverters.
Pure sine wave inverters are better suited for sensitive equipment and can prevent damage to computers. You may also have problems with other equipment on a modified sine wave inverter, from electrical noise to devices not working.
There are two main considerations when selecting an inverter 1. size of the inverter and 2. type of installation (Grid Tied, Hybrid or Off Grid).
What size inverter you should get?
What is the maximum load you will need to run off the inverter, and what is the average load that you will need to run off the inverter?
Your inverter should have a rated capacity greater than that of the peak load it needs to run – if you are going to use an inverter rated for 3KW and you try to run a 5 KW load even for seconds the inverter will shut down or even sustain damage.
For loads over a period of time, some inverters, even though they are rated ?kw may not be able to run at ?kw continuously, and may have a lower continuous rating than the rated peak.
Grid Tied Inverter
Grid tied inverters are inverters connected to municipal power and take power from a PV array to supplement the grid.
These inverters need power from the grid to operate. If there is a power failure your grid tied inverter will shut down and you would need a generator or a seperate battery backup system. Grid tied inverters are used to reduce your power consumption. Typically a larger commercial plant will use grid tied inverters as they are ideal for applications where the bulk of the power consumption is during the day. This will have significant reductions in the cost of power consumption because these systems produce power during periods when most of the power is being used.
Before going onto a grid tied solution it is essential to get a detailed analysis of your usage. An average of your consumption over a month is not ideal as you need to have a more detailed report of your power demand from hours to days including your maximum peak to have a system designed that will give you the best ROI.
Grid tied inverters are also used in residential applications where excess power can be pushed back into the grid, but for the most part this is not an option in South Africa. Most South African homes use less power during the day than at night so these systems are generally not ideal for residential solar plants.
Because the grid tied inverters do not use storage they are generally cheaper per KW than their Hybrid and Off-grid counterparts.
Off Grid Inverter
Simply put, off grid inverters operate independently from municipal power. They supply power to charge the batteries and fulfil the load demand and require enough storage capacity to maintain loads in bad weather conditions and for night time power consumption.
These systems are generally more expensive per KW than grid tied and hybrid inverters because more storage is required for longer periods to maintain loads and the high price of solar batteries.
Off grid solutions are best suited where there is no access to grid power or for applications where there is a smaller demand for power.
Using an off grid inverter solution for a residential plant in South Africa, depending on budget, would normally require lifestyle changes to make it more economical; for example, installing solar geysers and only using hot water once a day or using gas as a backup. Also, heavy-draw appliances like tumble dryers, dishwashers, kettles, hair dryers should not be used or limited – to run these off battery power will dramatically increase the overall cost of your solar plant.
For example, an average household using 40KW of power per day split equally between daytime and night-time usage would require at least 30 to 40KW of storage to maintain constant power. This does not include bad weather days. The amount of panels required would also then need to be sufficient to charge the storage and power the load during sunlight hours.
Full Hybrid Inverter
These inverters offer a combination of both grid tied and off grid inverters. They are capable of charging your batteries and supplementing the entire load, and have a backup for essential loads in the event of a power failure, The batteries can also be set to self-consumption which means they can be set to use the battery power to supplement the load when there is no power being generated from the PV array or the power being generated from the PV array is less than the demand.
Hybrid inverters have built-in feedback control to limit or stop power being exported to the grid which is essential for most South Africa solar installations.
Hybrid inverters will commonly have AC output for general consumption and an AC output for essentials backup loads – in the event of a grid power failure only the essential load will be maintained.
Hybrid inverters are ideal for most residential installations and, if designed correctly, will give the best return on your investment, especially in South Africa.