Unlike most alternative solar inverter assessment criteria, Solar Review assesses the purchasing elements which are important to the end-user. The purchasing decision is often comprised of 5 -6 main categories and accompanied by a range of influencing factors within each main category. By understanding each factor and referencing that to the current market, the Solar Review solar inverter assessment criteria has been derived.
The nominated scores are structured through available technical data and only limited discretionary values are available to the writer. Therefore, the majority of the values are in comparison to the industry best and worst. Considering that 5 stars are handed out far too liberally in the modern world for inferior products, the Solar Review inverter assessment criteria considers the industry average value (the middle) as 2.5 stars, accurately awarding those of which go above and beyond in diverse areas.
Within each of the above major categories are a variable amount of the common elements which may influence a purchasing decision. Below are the sub-categories and in-depth module assessment criteria.
Scores for each criteria and sub-category are evaluated as below;
5 - 4.8
The pinnacle of certified specification.
4.7 - 4.3
A rare calibre of technology produced by the industry elite.
4.2 - 3.8
Specifications which are exceedingly superior to that of the industry average.
3.7 - 3.3
Advanced technology against the industry average.
3.2 - 2.8
Better than the industry average is that of which strives a portion better.
2.7 - 2.3
A score within this bracket is considered the industry average specification.
2.2 - 1.8
Considered below the industry mainstream average.
1.7 - 1.3
There's better, there's also worse.
1.2 - 0.8
Far below the modern industry average.
0.7 - 0.3
Possesses specifications which are absent or unverified by a certified testing institute.
0.2 - 0
Unlikely for technology manufactured in the modern era.
Battery Compatibility | Newness | Cooling | Awards | Build | IP rating
Battery Compatibility. A key factor many end-users consider in order to maximise solar utilisation is what are the energy storage options available? Some inverters are better equiped at this than others. However, it will almost always depend o the battery selection which defines compatibility. That being said, and whilst being in the midst of a solar inverter technology evolution there are 5 main groups of battery compatibility from a singular solar inverter design; Hybrid/ Multimode with EPS (Emergency Power Supply), Hybrid/ Mulitmode without EPS, DC Coupled, AC Coupled only, No compatibility.
Newness. Solar inverters are so much more than DC to AC power supplies today. Aspiring towards consistent improvement and innovation is everything within the technology world. If a design has been lingering for more than 5-years it is outdated as the available technology to manufacturers to utilise has improved greatly. Even if the external housing has not wavered over time, internal advancements and modifications highlight consistent refinement from a manufacturer.
Cooling. Internally regulated fan cooling presents noise and more serviceable components than required from a modern residential solar inverter. With an often higher positive temperature derating point, convection cooling is quieter and reduces the need for service within an inverters lifetime.
Awards. Internationally recognised awards within the solar and energy storage industry don’t come much more esteemed than an Intersolar award. Both top place and runner-up in a category present an exceptional product within a nominated year. Some products, however, may not flag on an Intersolar award radar yet still cause ripples within alternative respected avenues. This should not be ignored if a certain body is a respected voice.
Build. The only design feature based on a discretionary assessment. Looking at the overall international market and what solar inverter types are commercially available at the time of writing, the Solar Review writer, with an educated opinion selects whether the particular module is either innovative, inspiring, standard, uninspiring or out-of-date.
IP Rating. Can the inverter design endure both indoor and outdoor installation? A solar inverters ingress protection rating highlights a solar inverters resistance to both dust and water (not sunlight) to an internationally recognised standard.
MPPT | Display | Internet Connectivity | Inbuilt DC isolator | 1st Party Module-Level Optimisation Options | 1st Party Rapid Shut Down Options | 1st Party Expanded Monitoring Options | Shadow Management Protocol | Remote Access Support
MPPT (Multiple Power Point Tracker). Two maximum power point trackers are becoming the expectation within an inverters features from units 3 kW and above. Few central inverter technologies are beginning to innovate to now facilitate three MPPT’s. Micro inverters and mandatory optimiser inverter technologies are considered feature rich in this area although only possessing one MPPT.
Internet Connectivity. The internet is opening up an inverters features like never before. Therefore, ease and ability of internet connectivity is essential. Modern advanced inverters are equiped with the ability to communicate through three main option. WiFi for wireless connection to a local router, ethernet for fixed line data transmission to a local router and 4G for wireless connectivity through a local mobile network.
Inbuilt DC Isolator. In systems where a DC isolator is required, having an inbuilt DC isolator minimises the required 3rd party accessories when installing a solar inverter. The result is a neater and more wholistic inverter solution.
1st Party Expanded Module-Level Optimisation Options. Having ensured a solar inverter with a 1st party module-level optimisation solution facilitates a more seamless optimisation option if required immediately or in the future. Often reducing the need for additional communication devices and lowering the capital cost to integrate.
1st Party Expanded Rapid Shut Down Options. Essential in some parts of the world, not so critical in other regions. However, having the option to integrate a manufacturer supplied Rapid Shut Down option is likely to reduce potential warranty conflict and ensure a seamless one supply solution.
1st Party Expanded Monitoring Options. Expanded system monitoring options facilitate the opportunity for and end-user to get the most from a nominated system by seeing the whole picture. Often labelled as the key to energy saving success, a manufacturer supplied expanded monitoring option ensures conflict free communication within the one singular monitoring platform.
Shadow Management Protocol. Dual MPPT’s can be considered a form of shadow management. Although, today there are greater onboard protocols certain manufacturers have innovated to deliver a more advanced form of shadow management. The most advanced form of shadow management though must be considered as mandatory module-level optimisation via one form or another.
Remote Access Support. As internet connectivity changes what we expect from an inverter, the internet has also changed the way we can support it. The pinnacle is for remote installer access to key operating parameters. An option which can expedite the a resolution to variable system errors brought on by fluctuating local conditions.
European weighted efficiency | Negative Temperature Range | Positive Temperature Range | Positive Temperature Derating | Weight | Noise
European Weighted Efficiency. Why European weighted efficiency? Because it delivers a more useful insight into the inverters performance over a range as opposed to when the inverter is simply performing at its best in ideal conditions.
Negative Temperature Range. The absolute minimum temperature a solar inverter will operate in by specification and design.
Positive Temperature Range. The absolute maximum temperature a solar inverter will operate in by specification and design.
Positive Temperature Derating. The temperature point where an inverter will begin to derate in performance by specification and design.
Weight. As technology improves, so does the amount of weight a solar inverter requires to support AC to DC conversion and the incorporated features. The advantages to a reduced weight design are experienced in logistics, installation, load baring, operational performance (less heat retention) and future maintenance if required.
Noise. Should one expect a noisy solar inverter operation? It depends on the size. For residential purposes noise can be a make or break factor for some. Understanding the level of noise emission is crucial especially when particular makes and models can operate virtually silent.
Parts Period | Labour Period | Authorised (trained) Installer Network
Parts Period. How many years is the solar inverters internal components or general operation guaranteed? An entirely different prospect over Labour guarantee period which may only be a portion of the offering.
Labour Period. Not all inverter warranties include labour and logistics for the entire stated period. Understand the period of which an inverter manufacturer will support the product including labour and logistics. Better assurance of an expense free warranty claim if required.
Authorised Installer Network. More and more proactive manufacturers are offering greater assurance to end-users when purchasing an inverter through a manufacturer accredited channel. Why? Because trained professionals achieve greater results for the products integrity in the field. Beyond an industry endorsement such as a licence, products have unique features which are not common knowledge presented by industry training. Therefore, it’s recommended that end-users seek out industry endorsed and manufacturer accredited professionals.
See Solar Review Monitoring Assessment Criteria.
Solar Review Monitoring Assessment Criteria 2.5 > (Coming soon)
Technology Aggregate | Market Pricing Index
Technology Aggregate. Omitted 2020.
Market Pricing index. Omitted 2020.
Detailed Scorecard Report (COMING SOON).
Detailed Solar Review Inverter Assessment Criteria reports will be available for purchase within each individual product review. If you require an in depth product analysis for a purchasing decision, the Solar Review Inverter Assessment Criteria reports are a must.