InvertersSolar Panels

Why Do Solar Cells Need an Inverter?

By:Michael Johns

solar cell inverter

You can’t run the majority of appliances and electronics directly from a solar panel.

This is because solar cells, which absorb sunlight and turn it into electricity, produce the wrong type of current.

A solar cell produces direct current (DC) while most electronics need alternating current (AC).

An inverter is a device that converts DC electricity into AC electricity.

Solar cells need an inverter to make this electrical conversion in order to run home appliances such as TVs, computers, microwaves, and washing machines.

Adding to this, the voltage of solar cells is usually 12V, 24V, or 48V while appliances need a higher voltage of 120V or 240V to run.

What is a Solar Cell?

A solar cell is a small square of photovoltaic material which absorbs photons of sunlight to energize electrons and produce electricity. If you look closely at a solar panel you will see that it is made up of lots of smaller pieces, these are the solar cells.

Usually, these cells are made from silicon crystal which are semiconductors. On a residential solar panel, you will find 60 or 72 cells making up each panel. Each cell can convert sunlight into a small amount of electricity so you need to use multiple to create a usable electrical output.

Why Don’t Solar Cells Produce AC?

Solar cells work by absorbing photons of sunlight which energizes electrons and creates an electric field. With this method of electricity production, the electrons all move in the same current direction. Because the electrons only move in a single direction, directly from A to B, it is known as direct current or ‘DC’.

In an AC current, the electrons regularly switch direction of flow from positive to negative. This switch happens 50 or 60 times a second. Unfortunately, it is not possible to generate AC from solar panels. This is why you require an inverter to make the conversion.  

Another reason for solar panels to produce DC rather than AC is storage. Often, solar panels are used to charge deep cycle batteries to keep the electricity for later when there is no sun. You can’t store AC electricity in a battery, you can only store DC.

What is an Inverter and How Does it Work?

An inverter is a device that converts the electricity produced by a solar panel into the type of electricity appliances need to operate. It does this by taking the DC power produced by solar cells and oscillating it. This oscillation changes the flow of electrons which then alternate between positive and negative direction of travel in a circuit. This is why it’s called alternating current or ‘AC’.

So an inverter converts DC to AC. 

In addition, it increases the voltage of the electricity. Voltage is the force of electricity, a bit like water pressure. You can imagine electricity flowing in a wire like water in a hose. The higher the voltage the higher pressure. An inverter will increase voltage from 12V, 24V, or 48V solar panels to 120V or 240V needed by appliances.

This conversion process also means that the electricity supply matches the main grid which is 120V AC in the US and 240V AC in the UK.

Types of Inverter

There are various types of inverters you can use with solar panels. All of them make the same conversion but are designed to work with different components after the conversion is made.

solar cell inverter
Off-grid, Grid-tie, and Micro Inverter

Off-grid Solar Inverter – These are designed to be used in a completely off-grid fashion where there is no connection to the mains. They are used when a solar panel charges a battery and then you draw and convert power from the battery with the inverter.

Grid-tie Solar Inverter – Grid-tie inverters are used with buildings that have a connection to the main grid. These systems don’t need batteries as you can use electricity from the solar panels and the main grid. The electricity is sent from the solar panel to the inverter and then directly into the building grid to run appliances. They have an added benefit of being able to send excess electricity into the main grid rather than storing it.

Micro Inverter – This is a mini inverter which attaches directly to an individual solar panel. Usually, you have one inverter to run all your solar panels in a system. With a micro inverter, each solar panel has its own tiny inverter to make the DC to AC conversion immediately.

Why is AC Electricity Used at Home?

The reason the majority of electronics and homes use AC is down to the way the main grid is created. To transport electricity from power stations to individual buildings it is more efficient to use AC. This is because it is easier to transform AC voltage during transportation.

If the electricity supplier wanted to give you DC electricity at home they would need to install extra equipment near your house to deliver DC from the existing AC network. Naturally, that costs more money and is impractical.

Electricity is easier to transport as in alternating current
Electricity is easier to transport as in alternating current

Home Appliances Use AC

Due to this design and electricity supply from the main grid, the vast majority of appliances are built to run directly from AC electricity. Once again this reduces the need for extra equipment and conversions in electricity type.

That being said, you can still buy many low voltage DC electronics to use at home. Electronics that use battery charging, like phones and tablets, are actually DC and the charging plug will make the AC to DC conversion. Remember, you can’t store AC in a battery! 

Plus many RV and camping appliances are built to run from DC so you can use them from a solar panel or battery without an inverter.

Can Solar Panels Work Without an Inverter?

Yes, absolutely! Solar panels will still generate electricity without an inverter. The inverter is simply used to make an electrical conversion. You can use a solar panel for a number of reasons without an inverter. 

Charge Battery

To charge a deep-cycle battery, like in a boat or RV, you don’t need an inverter. You can attach a solar panel to a battery (via a charge controller) to charge the battery with DC electricity. You could then draw DC power to compatible devices or use an inverter to make the conversion.

Run DC Device

There are many common devices that run on DC electricity. This means you can run or charge them directly from a solar panel or solar battery. There would be no need for an inverter! Here are some examples of what you could run from solar cells:

  • Smartphone
  • Flashlight
  • Electric vehicle
  • Electric toothbrush
  • 12V camping fridge
  • Digital camera

Final Words on Why Solar Cells Need an Inverter

By now you should clearly understand the function of an inverter for solar cells.

It is a simple case of converting the type of electricity produced by a solar panel into the type of electricity needed by electronic appliances.

Without an inverter, solar cells would not be able to supply the power needed to run appliances designed for the main grid.

That’s it! Thanks for reading.