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Best solar power inverter

Solar Power Inverters

Before we get into what is the best solar power inverter for your home, lets discuss what the different types are and what they do.

The inverter for solar panels is often called the “brain” of the Solar PV system. This is because its main function is to convert Direct Current (DC) from the PV panel into useable Alternating Current (AC). This can easily power common household appliances. Inverters also offer other functions, such as allowing you to monitor your system’s performance.

Off grid or Grid tied?

The most popular category of inverter is the grid-connected inverters, which are designed to operate only when connected to a mains power connection.

Off-grid inverters are designed to work without a grid connection and tend to be more expensive than grid tied inverter solutions. They would normally work in conjunction with other pieces of equipment, like batteries, to store the power.

These inverters often have different voltage characteristics than grid-connected inverters, so they should not be considered if a mains supply is part of the installation.

Different types of inverters

Lets first of all talk about the different type of inverters. These are:

  • String Inverters
  • Optimised String Inverters
  • Micro Solar Inverters
  • Hybrid Solar Inverters
  • Off Grid Inverters

String Inverters

Most homes use an electric generator to run an air conditioning unit. A single-phase or three-phase inverter is required, depending on the type of incoming supply you have. The majority of domestic installations will be single phase, whereas the majority of commercial installations will be three phase.

A single phase inverter can run on each stage of a 3 phase supply, however a 3 phase inverter cannot run off of only one stage in a power grid.

Inverters with string inverters are more efficient since they can accept several panels in series, increasing the incoming DC voltage. When the panels are connected in this manner, they are known as a “string”. The inverter is set to the total power of the installed solar panels, but careful planning must be taken into account when designing the system. This is to make sure that the PV panel string voltage and current are suitable for the inverter.

MPPT

The term “MPPT” refers to Multi-Point Power Tracking in grid-connected inverters. The manufacturer’s labelling will say if the inverter has 1, 2, or more MPPTs (Multi-Point Power Tracking). When the DC power from the panels varies owing to weather or orientation, this is where the DC connection point comes into play.

For over 20 years, traditional string inverter technology has been used. It is a well-known technology that has been tested and refined over time. In certain situations, it might have drawbacks. The power output from a string of solar panels will always be less than the least productive panel.

If one or more of your solar panels are shaded for any length of time during the day, the entire string’s electricity production will be reduced to its level. As a result, if you can’t run all of your solar panels on two MPPTs because they’re facing different directions and it’s tough to keep them running, boosting their performance is accomplished by optimizing them.

Some manufacturers produce a different type of inverter which doesn’t have MPPT but does allow installation in a single string. This string has electronic high frequency control and optimization which allows panels to be switched on and off individually to maximize output.

Optimised String Inverters

String Inverters with optimisers work similarly to a sting inverter, but each panel has an attached optimiser. The purpose of the optimiser is to regulate each module and ensure that maximum power is harvested from each module. This helps relieve the effects of shading on the PV array and maximises overall array output. Typically, optimizers can produce anywhere between 5% – 20% more power depending on the amount of shading at the site.

Customers also install solar panel optimisers for greater safety in case of fire. The switch can be activated to isolate the module at module level, preventing Direct Current (DC) from entering the building.

Array Optimisers

PV array optimisers offer the advantage of module-level monitoring. This allows you to see how each module is performing in real time. This can be useful for spotting any performance issues before they lead to significant generation loss.

Inverters with Optimizers are generally more costly than string inverters, although they can sometimes improve the Return On Investment of the system owing to their increased performance.

The two principle brands in the market are SolarEdge inverters and TIGO, who offer solar optimisers that work with any string inverter. SolarEdge also provides a number of smart home solutions and EV charging points.

Optimisers typically have 20-year warranties, while string inverters come with 5-10 year warranties.

Micro Solar Inverters

Microinverters are miniature inverters that convert DC to AC at the module level. A microinverter is usually included with each solar panel. Dual microinverters, on the other hand, imply that there are two panels for every single microinverter.

Among other benefits, microinverters offer module-level monitoring and the ability to run smaller single panel systems. Additionally, because the inverter is installed outside of the building, it improves safety. It does this by mitigating risks associated with having live electrical wiring inside a living or working space.

You will need a gateway installed with your microinverter in order to comply with G98 certification, regardless of the size of your array.

Though microinverter systems are usually the most expensive option, they also come with a warranty that is double the years of what other options provide.

Hybrid Solar Inverters

Batteries and hybrid inverters are manufactured to work together. An inverter transforms the DC to AC, while a battery manager is included. The battery manager will determine which batteries the hybrid inverter can be used with.

The current inverter models range from 3kW to 5kw for single phase and 5kW to 10kW for three phase.

When installing an inverter, you may want to consider a hybrid option. This will be cheaper up front, and if you choose to add a battery later on, it won’t cost as much.

When retrofitting a battery, you have the option of an AC or DC coupled unit. An AC system is a battery manager with an internal inverter, while in a DC system the power is returned through the PV inverter.

The most well-known hybrid brands in the UK are Solis, SolaX, SolarEdge, Victron and SMA.

Off Grid Inverters

One of the most popular off grid inverters is the Pure Sine Wave Inverter.

A pure sine wave inverter changes DC to AC by producing a continuous wave that describes a smooth, repetitive oscillation. This sine wave is the ideal waveform for transfer of AC power and has low harmonic distortion. The output of pure sine wave inverters typically equals or surpasses the quality of power at home. This means that it can safely run any electronic without risk.

Sine wave inverters usually have an in-built AC plug socket. If you want the Sine Wave inverter to work properly, you need to match the right kind of loads to it–including your peak load.

There are two types of inverters: pure sine wave (PSW) and modified sine wave. Pure sine wave inverters can be found from 300W to 5000W, and they’re the ideal choice for running solar systems in remote areas.

They are most often powered by a DC supply (usually battery) of 12V, 24V, or occasionally 48V for conversion to 230 Volts AC.

Still not sure which inverter is right for you

Let us, at Evergreen Solar Power, help you through the mine field that is everything solar power related. Whilst we do write these articles to give you the consumer the right information, nothing beats a phone call with the professionals to discuss your requirements.

Call us on 0800 0096625 during office hours or email us at info@myevergreenhome.co.uk 24 hours a day seven days a week

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