Inverters, Medium level, Sizing -

What size of inverter do I need?

 Sizing of Inverters 


The ‘quick and dirty’ answer:

As a very rough rule of thumb - same as your solar panel system; for a 6-kilowatt peak (kWp) system, you would need a 6-kW inverter.


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A more precise answer:

Solar inverters are one of the most important components of a solar panel system. They’re responsible for converting direct current (DC) electricity from your solar panels to alternating current (AC) electricity to power your appliances. The size of your inverter will play an important role in overall electricity production.


Solar inverters come in all different sizes, big and small. Similar to solar panels, the size of an inverter can be rated in watts (W). When it comes to solar inverter sizing, installers will take three primary factors into account: the size of your solar panel system, your geography, and site-specific conditions.


We assume you already have determined your power needs. If not, you can use this calculator to do that.


Your appliances

The right size inverter for your specific application depends on how much wattage your devices require. This information is usually printed somewhere on electronic devices, although it may show voltage and amperage ratings instead. Look at the biggest appliances that you want to connect to your solar system in terms of Wattage, e.g. water heaters, electric grills, air conditioners, Jacuzzi, etc.


Your inverter should be able to handle the peak Wattages that these appliances require. In general, inverters are able to handle a peak Wattage of a very limited duration for about 1.8 times the size of the inverter.


If it is going to be too expensive, you can decide to not connect these particular appliances to the solar power / backup system.


Your solar panel system

The size of your solar panels is the most important factor in determining the appropriate size for your solar inverter. Because your solar inverter converts DC electricity coming from the array, it needs to have the capacity to handle all the power the array produces. If you are installing a 6-kilowatt (kW) system, you can expect the proposed inverter to be around 6000 W, plus or minus a small percentage.


Solar installers will account for all considerations and efficiencies in your particular situation to determine what your solar panel system will produce in a real-life scenario. Solar panel systems that experience more shade, are at a sub-optimal tilt, or facing east rather than due North have higher derating factors than systems on sunny, North-facing roofs.


The array-to-inverter ratio of a solar panel system is the DC rating of your solar array divided by the maximum AC output of your inverter. For example, if your array is 6 kW with a 6000 W inverter, the array-to-inverter ratio is 1. If you install the same sized array with a 5000 inverter, the ratio is 1.2. The majority of installations will have a ratio between 1.15 to 1.25; inverter manufacturers and solar system designers typically do not recommend a ratio higher than 1.55.


Have a look at SunStore's Inverters: Click Here


Read more:

SunStore Solar System Sizing Calculator
9 Easy Steps towards installing Solar
Solar panels - What to Look for when Buying Panels 
Wiring solar panels: Series or parallel?
What DC Wire Sizes to use for your Solar PV System?
What size of inverter do I need?
What are the elements of a Solar PV system?
Iron or Ion ???? Lithium batteries explained...


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