The Difference between Microinverter and String Inverter Solar Systems

Solar technology is evolving; with options ranging across microinverters, string inverters and string inverters with DC optimizers. Choosing the right solar option may initially appear confusing but it doesn’t have to be.

What makes microinverter technology more advanced than string inverters is that microinverters allow for each panel to operate independently, thereby eliminating string failure issues, improving safety and maximising production output/efficiency.

So the question you need to ask is not, “which solar option is best for me?”, but, “which solar option is safer, better performing and more flexible?”

When it comes to inverters, Enphase microinverters offer superior performance compared to conventional string inverter systems. Here’s why:

Enphase Inverters String Inverters String Inverters with DC Optimisers
Safety Start-up voltage is 22 

VMicro-Inverter systems avoid the need for high voltage DC cable runs. Maximum voltage does not exceed 60 volts

Start-up voltage between 800V – 200V 

Maximum voltage reaches up to 1000 volts DC on the roof

Start-up voltage between 800V – 200V or moreMaximum voltage reaches up to 1000 volts DC on the roof
Performance Produces 3.1% more energy than string inverters 

Efficiency is panel-based

Energy production is dependant on the number of panels 

Efficiency is system based

Energy production is dependant on the number of panelsEfficiency is system based
Flexible Design Multiple rooftop configurations. 

Easily Expandable

Rigid Design due to string sizing, roof configuration and DC and AC electrical work 

Expansion may require inverter replacement

Rigid Design due to string sizing, roof configuration and DC and AC electrical work 

Expansion may require inverter replacement

Benefits of Enphase Microinverters

Image: Image Credit Enphase Microinverters v String Inverters

1. Performance: Enphase Microinverters vs String Inverter Solar Systems

The key difference is that with the microinverter system each SOLAR PANEL HAS ITS OWN ENPHASE MICROINVERTER mounted directly beneath it. This design increases production efficiency by immediately converting the ‘dirty ‘ DC power from the panel into ‘clean’ energy AC power which is fed directly into the grid. The main advantage of this design compared to string inverters is that it allows each panel to output power independent of other panels, dramatically increasing the systems production output.

Another big advantage of microinverters over DC string inverters is how they deal with shading. Whether it’s trees shading panels or bird droppings over panels, shading can significantly decrease the production of a system. In string and DC inverters, solar panels are wired in a series. If at any point panels are restricted, the entire series will drop in capacity. This will result in a reduction in the flow of electricity and decreased production.

A microinverter system doesn’t have that problem. Because each microinverter runs independently of the others in the system, only the panels that are under shade or have bird droppings on them will decrease production. Also, if you have an issue or a failure with a panel the complete system won’t go into shutdown only the one affected panel/inverter. Therefore the system will continue to produce and you keep saving money.

2. Safety: Enphase Microinverters Vs String Inverter Solar Systems Voltage

The AC microinverter system removes the need to install high voltage DC cables. AC microinverters have between 40 and 240 volts AC being delivered. DC inverters on the other hand have significantly more voltage (1000V DC) running down the cabling and through the roof of your home increasing greater chances of fire risk, power leakage and efficiency losses.

3. Flexibility: Enphase Microinverters Vs String Inverter Solar Systems Extensions

Another significant advantage microinverters have over string solar systems is the ability to increase their capacity. If you may at some stage have additional people living in the home or want to add extra air conditioning, it’s important to be aware that string inverters can only handle a defined level of capacity. If additional capacity is required you have two options 1) upgrade to a larger inverter unit or 2) adding additional panels but this is limited to the existing inverter’s capacity. A microinverter system allows you to keep building additional microinverters in line with your needs. Simply add another panel and inverter, no need to replace any pre-existing solar components.

The other problem with adding additional panels to a string inverter system is, because the panels are wired in a series configuration any new panel must be of similar specifications/ capacity. As technology improves so does the capacity and size of the panel. What happens is that the older panel specifications/ capacity is no longer compatible with the newly designed panels therefore the new and the old cannot be joined on the same string. As such, if you can no longer obtain the same capacity panels then all the panels would need replacing. Alternatively, microinverters can be matched to any size panel due to the individual operation of each microinverter.

4. Versatility: Relative to the supply into the property and battery-readiness

Whether you have single-phase power or 3 phase power feeding your home, the microinverter can be balanced across the home’s electrical infrastructure simply by installing a single or 3 phase interconnecting cable run between the microinverters.The Enphase microinverter is a smart hybrid system and is battery ready. Enphase produces its own battery system which due to the simplicity of the product allows for quick and compact installation of a battery system when required.

5. Support: Enphase offers remote support

Enphase provides monthly reports that identify system faults, production and consumption comparisons and the overall performance of the system to all clients that install the Enphase system. The Enphase monitoring platform can be individualised to your requirements. The platform is user friendly and at a glance, the user can see how the home or business is consuming power and whether the system is feeding power into the grid. Your Scholz Solar installer will demonstrate the platform once the system is commissioned and collecting data.

The Enphase microinverter is certified as a premium inverter. Whilst you will generally pay more for a microinverter system you will decrease your payback time through the added production efficiency that you get from the Enphase microinverter system. Still have questions? Contact Scholz Solar. Our knowledgeable staff can provide you with the answers.