Enphase Microinverter and Battery Review
Microinverters are a popular alternative to common 'string' solar inverters and are used in over half of all solar installations in North America. Microinverters, also known as micros, have several advantages over string solar inverters but a marginally higher upfront cost. In this article, we examine whether it is worth paying extra and what advantages micro inverters have over standard string inverters. For those new to solar, learn the basics of how solar works here.
Enphase Microinverters Quick Summary
Power rating: 240VA to 380VA AC (230W - 540W DC)
Latest products: IQ8 Micros, IQ battery 5P, Bidirectional EV charger
Battery compatible - Yes (AC-coupled batteries only)
Off-grid compatible - Yes (with Encharge battery & IQ8 micros)
Product Warranty: 25 Years (USA & Canada), 10 Years (Australia)
Service and support: Very good 5/5
Price bracket: High $$$$
Overall: Highly recommended ☆☆☆☆☆
Enphase Energy, founded in 2006, has long been regarded as the world leading microinverter manufacturer. Based in the US, Enphase launched the first microinverter, the M175 in 2008, but it wasn’t until the next-gen M190 was launched in 2009 that sales really took off. Ever since Enphase has established itself as an industry leader in microinverter technology and has a huge market share in North America. Sales in other regions, such as Europe and Australia, have been low in comparison but are growing as both consumers and installers realise the many benefits of microinverters.
What is a Microinverter?
Enphase microinverter mounted on a solar rail for demonstration. Image credit Lakeside Electrical.
A microinverter is a very small inverter designed to be attached to each individual solar panel. This is very different to standard string solar inverters, which are usually located on a wall some distance from the string of solar panels and connected via DC cable. In string inverter systems, DC power from the string of the panels is then converted to AC at the inverter. Since micro Inverters are attached to every solar panel, each panel works independently from the rest of the solar array and DC power is converted to AC immediately on the roof. Some solar panels are also available with factory-installed microinverters, referred to as AC solar modules.
Note: most benefits of microinverters only apply to high-quality microinverters such as those from Enphase Energy. Unknown or poor-quality micros should be avoided due to the history of high failure rates.
Advantages of Microinverters
The main advantage of microinverters is that each panel is monitored and optimized individually to generate maximum power. Solar panels can generate different amounts of power due to a number of reasons, such as shading, dirt and mismatch. In a standard solar installation using a regular solar inverter, the panels are linked together in a series of strings, and the power output of the entire string can be significantly reduced by a single poor-performing, shaded or dirty panel. More importantly, regular hard shading on a portion of a panel from rooftop-mounted obstacles such as a chimney can result in accelerated failure of the internal bypass diodes. This can potentially lead to a catastrophic failure due to reverse current and overheating. Learn more about how shading can cause bypass diodes to fail.
Solar systems can underperform due to the following reasons:
Shading – Trees, buildings, poles, wires, antennas, or rooftop structures
Blown diodes - Failed Bypass diodes due to partial shading from fixed objects.
Soiling – Dust, snow, bird droppings or birds
Panel mismatch – various manufacturing tolerances
Panel faults – micro cracking, hot spots or water ingress
Temperature difference – thermal mismatch at different times of the day
Panel Ageing - Panel degradation at different rates over time
PID – Potential Induced degradation (PID)
Odd roof layouts - Panels mounted at multiple orientations and angles
Microinverters can overcome these issues and help avoid the many reasons solar systems can underperform. For example, the performance of a regular solar inverter system will be significantly affected by one or more shaded or dirty panels or if a panel has a fault, such as a hot spot, blown diode or severe degradation. Conversely, microinverters avoid all these potential issues since each panel is managed and controlled independently.
Microinverters will perform better than string inverters if shading is a problem.
Further advantages of microinverters over string inverters
Enphase microinverters mounted on the solar rails prior to the panels being installed. Image credit Lakeside Electrical.
Considering the issues listed above, microinverters can significantly improve performance as they allow all panels to operate at their maximum power point (MPP) and not be affected by the lower performance of other panels. Another advantage of micros is the ability to locate panels on multiple sections of complex roof layouts with different orientations and tilt angles. Unlike string inverters, microinverters are not restricted to panel placement which is generally limited to two or three different orientations. String inverters generally have only two string inputs (MPPTs) and thus can only work with two groups of panels. Furthermore, the strings must have enough voltage to operate the inverter, which means they typically need to be at least four panels in a string. Microinverter systems are not restricted by any of these limitations.
No single point of failure
Not limited by string voltages
Easily expanded with a different model or newer panels
Microinverter systems have no single point of failure, which is particularly important in a large system with many panels. This means that unlike with string inverter systems, if one panel or microinverter has a serious fault, the rest of the system is unaffected, and it doesn't result in a complete loss of generation.
Enphase Microinverter Range
Enphase Energy has two families of microinverters: the older seventh-generation IQ7 series and the new eighth-generation IQ8 series. IQ8 micros are available in an extensive range of sizes to suit specific panel sizes and voltages, in particular, the more powerful commercial solar panels rated up to 600W. The latest micro to be added to the IQ8 lineup is the IQ8-3P, the first 3-Phase microinverter by Enphase.
Related discussion forum topic: Enphase IQ7 vs IQ8 Micros8
IQ7 Series
The IQ7 series has been around since 2018, and several new variations have been released over the years, the latest being the more powerful smart grid-ready IQ7A microinverter. Due to increasingly larger and more powerful solar panels coming into the market, the IQ7A has a higher continuous power rating of 349VA, up from 320V on the IQ7X. However, unlike the IQ7X, the maximum DC input voltage is limited to 58V, which is compatible with the latest 60 and 72-cell panels, or 120 and 144 half-cut high-powered solar panels up to 460W. The 96-cell panels, such as those from Sunpower and Panasonic, are only compatible with the IQ7X.
Download the full datasheets - Enphase IQ7, IQ7+ & IQ7X datasheet. Enphase IQ7A datasheet
The latest Enphase Mircoinverter range, specifications and solar panel compatibility - IQ7+, IQ7X and IQ7A
IQ8 Series
The eighth-generation microinverters from Enphase are finally available and packed with innovations to enable advanced grid-forming functions for off-grid operation and precise power control. Claimed as “the industry’s first grid-forming microinverters with split-phase power conversion capability”, the IQ8 range is available in an extensive range of sizes from 240VA up to 380VA to suit almost every panel type from the old generation 60-cell panels up to the latest powerful 540W + panels used for large commercial installations.
Enphase IQ8 Series microinverter range, specifications and solar panel compatibility.
Where the IQ8 series really shines in is speed and accuracy thanks to the “proprietary application-specific integrated circuit (ASIC)” which enables the microinverter to become a rapid load-following inverter to allow seamless operation in both on-grid and off-grid modes. Additionally, the IQ8 series micros are designed to work in conjunction with the new range of Enphase battery storage equipment, including, the IQ Battery, IQ Gateway, and IQ system controller, described in more detail below.
IQ8 Advanced Features:
Grid-forming microinverters with split-phase power conversion
Seamless transition between on-grid and off-grid modes
Basic backup power without a battery (during daylight hours)
Remote automatic updates for the latest grid requirements
Fully configurable to support a wide range of grid profiles
Download the detailed Enphase IQ8 series datasheet.
IQ8-3P - 3-Phase microinverters
Enphase Energy has introduced the new IQ8-3P commercial microinverters aimed at North America's small commercial solar market. The IQ8P-3P is the most powerful of the two options, with a peak output of 480W and compatible with solar panels ranging from 320W to 640W. The 3P microinverters are available for order in the US, Canada, and Mexico, with shipments projected to begin in the first quarter of 2024.
3-Phase Microinverter Features:
3-phase 208V commercial systems (US standard)
Compatible with 54, 60, 66, and 72-cell modules up to 640W.
New simplified three-phase cabling system
Corrosion-resistant polymeric enclosure
Built-in phase balancing, V/F ride-thru, and loss of phase detection
Built-in rapid shutdown
Standard 25-year limited warranty
Specifications of the new 3-Phase commercial IQ8 microinverters and IQ Gateways commercial 2
IQ Gateway Commercial 2
The new IQ Gateway Commercial 2 is designed for three-phase commercial systems and is compatible with IQ8P-3P and IQ8H-3P Microinverters. It introduces enhancements in production metering, including a larger 400 A CT. Other features include integrated production metering (up to 400 A) and consumption metering (up to 600 A) for three-phase services. The new gateway supports bidirectional communications for remote upgrades, along with export limiting and zero-export capability.
System and panel level monitoring
The IQ Gateway system monitoring device
Microinverters offer better system monitoring compared to string inverters, as each panel can be monitored individually. Note, for those with standard string inverter systems, additional panel-mounted 'DC optimizers' such as those from Tigo or SolarEdge can also enable individual panel-level monitoring and optimisation. However, the extra cost and real-world performance of these alternatives are debatable.
Enphase Enlighten monitoring and system management software enables individual panel level monitoring
With micros an owner can see the performance of the system as a whole, plus at the individual panel level. Also, the installer can have a separate login where they can monitor all their systems at a panel level and are warned when any panels are under-performing which can prevent system downtime and help with any warranty claims. Enphase Energy has the Envoy monitoring hub for all systems to enable setup, commissioning and remote monitoring. They also monitor all registered systems worldwide from the US headquarters which provides valuable information to monitor fault conditions and continue to improve their products.
The user friendly interactive Enphase Enlighten system monitoring app.
Reliability
Most microinverters have been rigorously tested in extreme weather and climate conditions. These units are designed to last the life of a solar panel and generally have a warranty to back that up. Many microinverters, such as those from Enphase, come with a 25-year warranty (10 years outside North America), which is far longer than the standard 10 years for most string inverters. Again, bear in mind that this is only relevant with high-quality microinverters such as those from Enphase. To date, there have been very low failure rates reported by our solar specialists, and Enphase has proven to be one of the most reliable inverter manufacturers in the world.
High Temperature Performance
Enphase tested and monitored the performance of their micro's during the 2014 Australia summer in Adelaide, which had the most consecutive days over 40C (104F) in its recorded history and peaked at 45.9C (115C). Because of the advanced monitoring of their inverters, they were able to announce that “No Enphase Micro inverter across Australia shut down due to high temperature” during this period. Other manufacturers also have very stringent testing of their inverters and have performed well in hot and freezing temperatures. It cannot be inferred that all micros are up to this standard, though and there are several competing brands that have recorded much higher failure rates by installers.
Safety - AC vs DC
Thermal image showing hot spots in a damaged solar panel which can lead to failure.
In standard string inverter systems, high-voltage DC electricity is sent via cables from the strings of panels, usually through the roof or wall cavities, to an inverter that converts the DC into AC electricity. If the cable is damaged, the high string voltage, which is often 400 to 500 volts, can cause dangerous arcing, which is very difficult to extinguish. Additionally, if a single cell is damaged in a panel, it will often turn into a hot spot due to the reverse current bias and high voltage, resulting in a thermal runaway that can burn the rear side of the cell. In a worst-case scenario, this can even result in a fire.
In a microinverter system, the panels produce DC power, which is immediately converted to AC on the roof. This is important because AC arcing can be easily detected and isolated, unlike high-voltage DC electricity, which is more likely to cause arcing and heating, leading to a potential fire. It is very important to bear in mind that fire from any solar system is very unlikely, especially if correct installation methods are taken.
Investment
Micro inverter manufacturers argue that whilst the upfront cost of their technology is higher than string inverters, they are better value over time. It stands to reason that if micros allow for greater performance and output of your solar system and are more reliable, then over time, they will have a better payback. Whether they do and by how much, depends on many factors, including; the difference in cost compared to a string inverter system, the amount of shading, the rate of panel degradation (including PID issues), and electricity tariffs.
Disadvantages and what to avoid
A factor that should be considered when looking at microinverters is that there are far more inverters in one solar installation than with a string inverter. In an 8kW system using 400W panels with micros on each panel, there will be 20 inverters. This means that if the micros being used have the same failure rate as a mid-range string inverter, there is 20 times more chance of a failure than with that string inverter. This leads to the obvious cost disadvantage; while a single microinverter is much cheaper than a string inverter, purchasing 20 microinverters is much more expensive than one string inverter. However, unlike string inverter systems, a single failed microinverter will not affect the rest of the system, and the remaining microinverters will continue to operate as normal.
The most apparent reason why microinverters may not be the best choice is due to the mounting location on the roof, where they are generally exposed to extreme heat, humidity and potentially salt mist when located near the ocean. This is where string inverters have the big advantage of being mounted in more protected locations or even indoors. Most microinverters are tested and built for these weather extremes, but over the years, some microinverters have had multiple faults, especially when in harsh conditions such as high humidity and in close proximity to the ocean with extreme salt corrosion.
Cost and Savings
A microinverter system's upfront cost is generally higher than a regular string inverter system. On smaller systems around 3-4kW, micros are comparable to string systems since the cost of one good quality string inverter is equivalent to the cost of 8-10 micros, which are relatively cheap. Although on a larger 8kW system, the cost difference becomes more significant as one single string inverter becomes significantly cheaper than 18 to 20 microinverters. However, microinverters have a significant cost advantage when it comes to upgrading a system in the future, as you do not have to replace the inverters with a newer, larger model. Microinverter systems are unique in that you can add additional panels, of a different make or model, without having the modify the existing system. Solar panel technology is advancing rapidly, so it is often impossible to source the exact model panel even after only one year. String inverter systems cannot mix different types of panels, and often the entire system has to be replaced to increase the solar capacity resulting in a far greater cost.
Enphase IQ battery system
The long-awaited IQ series battery system from Enphase was first announced in mid-2020, but it has taken almost three years to launch the IQ batteries globally. The IQ series batteries are AC-coupled, meaning they also contain an inverter-charger and are built around the next-generation IQ8 microinverters. The batteries were initially available in 2 sizes, the small 3T model, a 3.4kWh unit, and a larger 10T or 10.1kWh battery, which is technically three smaller batteries combined into one. However, as described below, a new, more powerful mid-size 5P battery was released in May 2023 with numerous updates and improvements.
Enphase engineered the IQ battery using their new IQ microinverter technology. It provides full backup capability thanks to embedded grid-forming IQ8 microinverters when installed with an IQ system controller containing the grid isolation device.
Enphase IQ Battery 5P
The second generation IQ battery from Enphase, the IQ Battery 5P, was released in May 2023 and is being rolled out globally. Each 5P battery has 5kWh of total usable storage capacity and can deliver 3.84 kW continuous power with a peak output of 7.68 kW for 3 seconds. More importantly, the power output of the 5P series can be increased using multiple batteries in parallel. Like all previous Enphase batteries, the 5P series also uses Lithium Ferro Phosphate (LFP) battery chemistry, which has the longest lifespan and is not prone to thermal runaway (fire) in case of an accident or failure.
The IQ Battery 5P is a fully modular system with 5kWh of usable capacity and can be configured with up to 16 units in parallel for a total of 80kWh. Backup power is enabled with the new IQ system controller 3. However, if backup is not required, the battery can work independently as a simple grid-tie battery for self-storage. Along with the new battery, Enphase upgraded the Energy System components, including the new IQ System Controller 3/3G and IQ Combiner 5/5C, which offer more resilient wired communication and improved system commissioning.
Download the full Enphase IQ Battery 5P datasheet.
Battery Warranty and Lifespan
The IQ Battery has an industry-leading 15-year warranty covering 6000 cycles, up from the 4000 cycles allowed on the previous 10T series battery. All batteries slowly lose capacity over time, and the end-of-life warranty specifies a minimum retained capacity of 60% after 15 years. Other battery manufacturers guarantee a minimum of 70% retained capacity after 10 years, which, at first, might appear to be better. However, considering the Enphase warranty period is 50% longer, this equates to a far greater battery life and is considerably better than most other battery manufacturers after an equivalent amount of time.
Enphase IQ 5P battery installation with 3 batteries and IQ System controller - System installed by Lakeside Electrical
IQ System Controller 2
The IQ system controller 2 is the heart of the new Enphase energy storage system and provides grid integration and seamless backup power in the event of a power outage. It enables a home micro-grid formation and combines all the required grid interconnection equipment into a compact aesthetic enclosure, making installation much quicker and easier. The controller is required to integrate solar, storage, and even a backup generator to enable off-grid functionality.
IQ System controller main features and functions:
Manages and controls grid connection
Automatically detects grid outages and transitions to backup
Supports whole and partial home backup
Neutral-forming transformer for split phase 120/240V backup operation
Provides integration for compatible (AC) standby generators
Compatible with IQ8-Series and previous generation Enphase microinverters
Enables prioritisation of power to critical loads during a grid outage when paired with the optional IQ Load Controller.
Download the full IQ system controller 2 datasheet
Enphase IQ system controller required for backup operation and integration of solar, battery storage and a backup generator.
Enphase Bidirectional EV charger
In early February 2023, Enphase launched a unique bidirectional EV charger built around the latest IQ8 microinverter technology, which enables both vehicle-to-grid (V2G) and vehicle-to-home (V2H) functionality. V2H enables a compatible EV to be used as battery storage and as a backup power source in the event of a power outage, while V2G enables an EV to feed power back into the electricity grid to help stabilise the grid. Learn more about V2G and V2H technology here.
Considering Enphase has not produced a regular home EV charger, the launch of a bidirectional charger came as a bit of a surprise. However, since the IQ8 microinverters are micro-bidirectional inverters and can operate in on-grid and off-grid modes, they were an ideal foundation for building a bidirectional charger and enabling seamless integration into the Enphase home energy ecosystem. The bidirectional charger is very similar to the Enphase Encharge battery system, but of course, in the case of the EV charger, the battery is inside the vehicle.
Enphase Bidirectional EV Charger Operating Modes
Vehicle-to-home (V2H) - EV is used to power a home during an outage.
Vehicle-to-grid (V2G) - Enables the EV to participate in grid support services.
Green charging - EV charging using solar only.
Self-consumption - Charging using solar, plus minimising grid consumption.
Savings mode - Charging during times of low tariffs, and powering the home during times of high tariffs to minimise electricity costs.
Enphase has not released a datasheet at this stage, so the exact details, including the charge and discharge ratings, are still unknown. The charger will be available in early 2024, but it is not known how much it will cost. Based on the information provided and the assumption that it is similar to the Encharge 10 battery system described above, it could be assumed that the power ratings will be rather modest at around 4 to 5kW. Despite the limited specifications available, Enphase has released a very good white paper explaining the various features and functions. Below is a modified diagram from the white paper to help explain the operating principles and some technical characteristics of the charger.
Enphase Bidirectional EV charger technical operation diagram
Black Start Battery Explained
One of the clever features of the Enphase bidirectional charger is the black start battery. If a blackout occurs while the EV is away, the charger can startup and communicate with the EV once it is connected. Otherwise, the V2H backup function would not be able to operate unless an additional backup power source was available.
Enphase Warranty
The standard Enphase microinverter warranty period in most countries is 10 years, the same warranty offered by leading string solar inverter manufacturers. However, in the US and Canada, the warranty is an impressive 25 years. It is unclear why this longer warranty is not offered outside the US; perhaps the higher cost of solar in the US plays a part in this, but it would be great if this were at least an option outside North America. See the full warranty details for all countries here.
Unfortunately, the longer warranty does not extend to the other Enphase products, including the Gateway, Envoy, CT meters and Combiner products, which are only covered by a 5-year warranty.
Enphase microinverter warranty details for Australia and New Zealand
Enphase microinverter warranty details for the US and Canada
Should you get Enphase microinverters?
There are many advantages to using Enphase microinverters and AC modules, especially when individual panel-level monitoring is required. However, microinverters have a slightly higher upfront cost for smaller systems than string inverter systems, and this price difference increases considerably for larger systems. A good-quality string inverter will be more economical if you are on a tight budget and have sizeable open roof areas with no shading issues. Until recently, microinverters were not a great option for those looking at energy storage. However, this has now changed with the advanced Enphase IQ8 energy storage system and intelligent controllers designed to seamlessly integrate solar, batteries and even backup generators to provide partial and full off-grid functionality.
If you are looking for a quality, safe, high-performance solar system with excellent monitoring, then quality microinverters from Enphase are easily one of the best options. For roofs with multiple aspects or shading issues, micros are a perfect choice, especially if each roof section is limited to a small number of panels. For commercial systems with many roof pitches and obstacles or where performance monitoring is critical, micros will offer many advantages and can offer a greater payback over the life of the system.
Based on years of feedback from solar installers across Australia and the US, Enphase is considered the best microinverter manufacturer due to the low failure rate, high quality, advanced system monitoring, and great service.
