SolarEdge Review
Founded in 2006, SolarEdge Technologies is rather unique among Inverter suppliers as they do not manufacture conventional string solar inverters but what the company refers to as ‘intelligent inverter systems’ using power optimisers to maximise power generation at the individual panel level. SolarEdge systems have long held a significant market share in the US and have increased in Australia. At the same time, European sales have also grown as customers discover the benefits of panel-level monitoring and optimisation to help reduce the impact of shading. However, there are some disadvantages, such as higher upfront costs and added complexity. In this article, we explain how the SolarEdge system works, the many advantages of using DC optimisers, and some of the difficulties with rooftop-mounted optimisers.
SolarEdge System Main Features & Benefits
Unique system with SolarEdge panel-mounted power optimisers
Helps reduce the negative effects of shading
Panel-level monitoring
Available in a wide range of sizes from 2.5kW to 10kW (single-phase)
Up to 300% solar oversizing allowed (refer to inverter datasheet)
Advanced safety features, including integrated arc fault protection
Communication via built-in Ethernet or Wi-Fi
Battery storage and smart energy products available for increased self-sufficiency
Industry-leading 12-year warranty (extendable to 20 or 25 years)
How the SolarEdge System Works
Before we explain how the SolarEdge systems work, I will quickly describe how a common string solar system works. Conventional solar inverters convert DC power from a string of interconnected solar panels to AC power. Depending on the weather conditions and time of day, this results in a wide range of string operating voltages. String inverters track the voltage and convert the DC power to AC at the maximum power point (MPP) of the entire string. This generally works well unless there is partial shading, dirty cells or issues with one or more panels, which often reduces the whole string power.
Optimisers are attached to each solar panel and connected via DC cable to the SolarEdge Inverter.
SolarEdge Inverters, on the other hand, operate at a very specific voltage (typically 380V). They work by using DC power optimisers connected to each solar panel. The power optimisers work like a maximum power point tracker (MPPT) and can either boost or reduce the panel voltage to deliver the optimum voltage to the inverter. If several panels are shaded or underperforming, resulting in low voltage or current, the other panel optimisers can compensate (up to a point) for the poor-performing panels and provide the optimum string voltage for maximum performance.
SolarEdge optimisers are DC-to-DC converters that work together to deliver the optimum string voltage to the inverter for maximum power.
Of course, there are some limitations to the SolarEdge system. For example, if multiple panels are shaded or underperforming, the optimisers can only compensate so much (as they have a limited range) before the system's performance is reduced. I should also mention power optimisers cannot generate additional power during bad weather or when most of the panels are dirty or shaded; they aren’t magic!
SolarEdge Power Optimisers Explained
Power Optimisers
SolarEdge Power Optimisers are small add-on electronic devices that enable each solar panel to operate at its maximum power. Power optimisers and microinverters are generally known in the industry as MLPE or Module Level Power Electronics, which, as the name suggests, consist of electronic power conversion units attached directly to individual solar panels. MLPEs offer a range of benefits, including power optimisation to ensure every panel performs at its peak power output and panel-level monitoring to provide real-time power generation data from every panel in a solar array. Using this, underperforming panels can also be highlighted and assessed for issues. DC optimisers also allow flexible system designs with multiple orientations, tilts and panel types in the same string.
Due to the vast array of solar panels available on the market with different power ratings (from 375W to 650W) and various operating voltages, SolarEdge has produced a wide range of optimisers explicitly designed for the many different types of panels and configurations. See the full power optimiser details.
The SolarEdge monitoring platform enables tracking and monitoring of every panel in a system. The below example shows an 18% difference between the highest and lowest-performing panel. While this roof would appear to suit a standard string inverter (being that all the panels are at the same orientation), without solar optimisers the few under-performing panels on the array would normally lower total performance.
The cloud based SolarEdge monitoring portal shows detailed panel level monitoring.
Benefits of Power Optimisers
Shading is one of the most common problems with standard string inverters and rooftop solar installations. However, with an optimised system if one or more panels is even partly shaded the optimisers bypass or compensate for the shaded panel/s without effecting the output of the other panels in the string.
Under partial shading the SolarEdge system can dramatically increase generation compared to traditional string inverter systems where shading of one panel reduces output of the whole string. Image credit: SolarEdge
Besides shading, there are many other reasons (listed below) why individual panels or strings can underperform or reduce performance. Even minor issues can become more problematic over time as PV systems age and can develop hotspots due to individual cells degrading at different rates. Different panel degradation rates (typically 2-3% in the first year and 0.5% per year after) can result in a 5-6% mismatch over the life of the system.
Eight factors that can reduce solar system performance:
Shading – trees, buildings, poles, wires, antennas, or rooftop structures
Panel damage – micro cracking, hot spots or water ingress
Soiling – Dust, snow, bird droppings or birds
Panel mismatch – due to various manufacturing tolerances
Blown diodes - Failed Bypass diodes due to partial shading from fixed objects
Temperature difference – thermal mismatch at different times of the day
Soiling – Dust, snow, bird droppings or birds
PID – Potential voltage leakage issues
PID issues, in particular, can be difficult to assess without specialised equipment. However, with the aid of individual panel-level monitoring, the SolarEdge system makes it much easier to identify faults like Potential Induced Degradation issues if they develop.
Additional Optimiser Benefits
The SolarEdge system offers additional benefits to solar installers regarding flexibility in design layouts, as described below. One significant benefit is when it comes to replacing old or faulty panels on systems in the future, it is often challenging to find the same size or model panel; optimisers overcome this as they can function with multiple panel sizes and models on the same string. For example, you can replace an old 300W panel, which is no longer available, with a 415W panel, and each panel will still operate at its maximum power point.
Added benefits of SolarEdge Optimisers
Multiple panel orientations on one string
Different panels on one string – ideal for upgrading old systems
Maximise roof space – shading in winter is less of an issue
Can install parallel strings of unequal lengths
Monitoring at the individual panel, string and inverter level.
Remote troubleshooting via the monitoring portal
Safety Benefits
In addition to the individual panel-level monitoring and power optimisation, SolarEdge optimisers offer a great safety advantage by reducing the DC cable voltage to 1 volt per panel if a grid or inverter shuts down. Strings of solar panels can be dangerous (during the daylight) as the DC voltages are usually 300-600 Volts, which can be hazardous in the event of a fire or an emergency.
High DC string voltages, combined with damaged connectors, faulty isolators, water ingress, or corrosion, can potentially lead to an arc fault, resulting in severe damage to the panels or, in the worst case, a rooftop fire. SolarEdge inverters also incorporate built-in art fault detection (UL1699B) to help mitigate the chance of arcing.
Added safety benefit - during installation, before the inverter is switched on, the voltage is reduced to a safe level with the DC string voltage corresponding to the number of panels in the string. ie. 12 panels = 12 volts DC.
SolarEdge Range of Solar Inverters
The compact HD wave residential inverters are available in a large range of sizes from 2.5kW to 10kW (single-phase). Like most inverter manufacturers, SolarEdge has followed suit and removed the display screen to help increase lifespan and reduce potential faults. The range of larger-scale 3-phase commercial inverters keeps growing, with inverters from 15kW through to 82.8kW and larger 100kW units in the pipeline.
Residential Inverter Range
Home Wave inverters from 2.5kW to 10kW
GENESIS (battery-ready) inverters from 3kW to 10kW
Home Hub hybrid inverters from 3.8kW to 11.4kW (US)
Home Hub hybrid inverters from 3.0kW to 10.0kW (AU)
3-Phase inverter range from 5.0 to 8.0kW
Commercial Inverter Range
3-phase range from 15kW to 27.6kW
3-phase range from 50kW to 100kW
SolarEdge Hybrid & battery-ready Inverters
SolarEdge offers a range of hybrid inverters for different applications, including:
1. StorEdge Inverters
The older generation StorEdge inverters have been around for many years and are only available in 5kW & 6kW sizes. These hybrid inverters are designed for maximising solar consumption through storage and self-use, plus providing backup power to essential circuits in the event of a blackout. The peak backup power ratings are respectable at 4.9kVA and 6.6kVA, higher than most of the competition. (But keep in mind it may be lower depending on the battery output power rating). Like most hybrid inverters, the StorEdge inverter is suitable for providing backup during short, infrequent blackouts. It is not suitable for off-grid solar installations.
2. Genesis Inverters
The new GENESIS HD-wave inverters are available for energy storage systems without backup power requirements. This is the most cost-effective solution for solar and energy storage but does not have backup power capability built-in like the new energy hub hybrid inverters described below. However, limited backup power is available with the optional StorEdge Interface module shown below. For non-back-up battery installations, the LG RESUH Prime battery range can also be used in conjunction with the HD Wave Inverter using the StorEdge Interface module.
3. Home Hub Inverters with backup interface
The next-generation hybrid inverters from SolarEdge are based on the same compact, lightweight HD-wave architecture. They are compatible with the new SolarEdge Energy Bank battery. These more advanced inverters have built-in battery connections that enable the batteries to be directly DC-coupled to the inverter, plus the optional backup interface unit, described below, can provide full backup power capability and generator input for an alternative AC supply.
Download the Home Hub inverter datasheet (US) or the Home Hub inverter datasheet (AU)
Home Hub inverters also contain an integrated energy meter and thus only require an external CT clamp on the grid supply side to measure household consumption; this enables full smart home capabilities and solar EV charging using an optional charger. Note an external CT meter is not required when used with the backup interface. Another helpful feature for homes with larger power requirements is the ability to combine multiple inverters in parallel for increased output and larger solar capacity.
Backup Interface box
The optional backup interface box provides full home backup, generator support and separation of essential (backup) and non-essential loads if required. The backup box unit is necessary to monitor and isolate the grid AC supply during an outage or disruption, enabling the home to operate in off-grid mode. It also features an integrated energy meter to enable smart energy management, including EV smart charging. Other key features include a 100A interconnection contactor (switch) and generator hardware support for an alternative AC supply rated up to 18kW/75A single-phase. Note an inverter firmware update is required for generator support.
Download the Backup Interface box datasheet
Controversy and Reliability
There have been many heated debates among solar installers and professionals over recent years about the reliability of rooftop-mounted panel optimisers and their effectiveness compared to traditional string inverter systems. No electrical system is ever free of faults, and much of the debate lies around the difficulty of replacing an optimiser if a problem occurs in a string. The problem may not be due to the optimiser itself but poor installation or a faulty connection. However, either way, the panel or panels have to be located and removed, which is often very difficult depending on the roof type, access and steepness. I have worked on many solar systems using different panel optimisers from SolarEdge and other leading brands, including Tigo and Huawei. All optimisers have encountered problems over the years, so the problem is not isolated to SolarEdge, but the difficulties remain the same.
Disadvantages of Optimisers
Installing optimisers adds to the total system cost due to the additional components required and more complex installation, with additional cables & connection points. Also, more connection points could lead to more failure points, especially if mismatched connectors are used. However, SolarEdge and many solar installers claim the benefits of panel-level monitoring, added DC safety, and power optimisation outweigh the additional setup cost and complexity. Having individual power electronics mounted on each panel could increase the likelihood of failures and technical problems over time as the optimisers are located on the rooftop in extreme conditions such as high temperatures and humidity. Some installers of SolarEdge products we interviewed have noticed increased failure rates in some extreme environments and issues claiming warranty.
A higher-than-average failure rate of rooftop optimisers has been noted by some Australian installers located in the tropics or areas with very high humidity. Despite this, the overall failure rate reported by SolarEdge and the installers we surveyed has been relatively low.
Faults and warranty claims
With the added benefits of individual panel monitoring, issues can be identified as SolarEdge also monitors all network-connected systems. Theoretically, any warranty issues should be easily handled and resolved as long as the system has been installed correctly. Unfortunately, making warranty claims and obtaining replacement parts from SolarEdge can be difficult. In some cases, installers have reported very long wait times of several months, leading to dissatisfied customers due to prolonged system downtime. That being said, issues around claiming warranty parts are an industry-wide problem,
Problems with small systems and excessive shading
Since SolarEdge residential inverters operate at 350V DC (380V for the HD wave) and the optimisers have a limited voltage range (60V to max 85V for P505), a minimum string size of 6 to 7 modules is required. Smaller systems with shading issues can be problematic. If too many modules are shaded, the system voltage will drop out of the inverter voltage range, resulting in poor performance. With this in mind, installations with excessive shading will not be suitable for small systems with less than 8 or 9 panels.
New Optimiser for long strings
Despite the ability of optimisers to mitigate the effects of shading, if a high proportion of panels in a string are shaded, then the total output will be significantly reduced, or the inverter may shut down if the voltage drops below the required voltage (380V).
To help overcome this, SolarEdge has updated the operating parameters and released a new P401 optimiser, allowing a long string of panels to be installed on multiple roof pitches and orientations. See the full installation guidelines here.
SolarEdge Energy Bank Battery
SolarEdge Battery
After a long wait, the new Energy Bank battery is finally here, enabling SolarEdge to offer a complete home solar energy storage system. The battery is a high-voltage DC-coupled battery module designed to be used with the SolarEdge Energy Hub inverters. Unlike traditional low-voltage (48V) storage batteries, the higher-voltage DC system is more efficient as it operates at a similar level to the rooftop solar array. This results in a lower operating current, increasing round-trip efficiency to 94.5% (claimed).
Battery Key Features
DC-coupled high-voltage lithium battery
9.7kWh usable capacity
5kW power rating, 7.5kW peak rating (10sec)
10-year warranty with a minimum 70% capacity
94.5% round-trip efficiency
Price range: $9600 to $10500
While it’s promoted as a 10kWh battery, the usable capacity is 9.7kWh. This is higher than many other batteries that are limited to 80 to 90% usable capacity to increase cycle life. Despite this, the SolarEdge battery warranty is ten years and offers a respectable 70% minimum retained capacity after the full warranty period, similar to most competitors’ warranty specifications.
The 5kW battery power rating is standard for a sizable 10kWh battery system. However, the surge or peak power rating is slightly above average at 7.5kW for 10 seconds, which is more than enough for most household loads. The surge power rating is critical during a blackout when excess energy cannot be drawn from the grid. For larger energy consumers, up to three batteries can be coupled to a single inverter, providing up to 29kWh of storage. Interestingly, the battery communicates wirelessly with the inverter, which may help eliminate problems with faulty comms cables or connections (if the wireless communications system is reliable).
Regarding pricing, the Energy Bank is much more expensive than the competition, costing close to $10,000, equating to $1000 per kWh. This is well above other popular high-voltage batteries, such as the LG RESUH Prime at $750 per kWh and the BYD HVM battery system at $815 per kWh.
Download the SolarEdge energy bank battery datasheet.
SolarEdge EV chargers
SolarEdge has produced several devices for electric vehicle charging including the first integrated solar inverter and EV charger. This unique 2-in-1 inverter solution can charge from solar and the grid simultaneously with a power rating up to 7.4kW (32A). See how it compares to other EV chargers in our best smart EV chargers review.
SolarEdge also offers a dedicated EV charger rated up to 9.6kW or 40A, which is higher than most single-phase EV chargers which are limited to 7.4kW (32A). The smart EV charger is monitored and controlled via the SolarEdge app and includes smart scheduling and charging history. When coupled with a SolarEdge solar inverter it enables the full range of smart charging features including load balancing, solar-only charging and fast (boost) charging. Learn more about solar EV charging.
Download the full SolarEdge Smart EV Charger specifications.
SolarEdge App and Monitoring Portal
Like most solar inverters on the market, SolarEdge offers a free cloud-based system monitoring portal that provides solar generation and consumption monitoring (with an additional energy meter). However, unlike most others, the SolarEdge portal can also offer detailed panel-level monitoring (provided it is enabled), plus a suite of smart home control features that can be used to control home appliances and specified loads with the additional SolarEdge smart energy products.
The SolarEdge smart energy monitoring platform, also available on mobile app, for remote control and monitoring of specific ‘smart control’ appliances.
Warranty
SolarEdge offers a 25-year warranty on all power optimisers and a leading 12-year warranty on all inverters with optional extensions of 20 or 25 years. Of course, a warranty is only useful if the company is around in the future to support it and SolarEdge is doing very well so this would not be a problem.
Some of our solar professionals have noted warranty claims can be problematic with SolarEdge and generally take longer to resolve than other manufacturers.
Download the SolarEdge warranty certificate details.
Should you buy a solarEdge system?
SolarEdge inverters and optimisers can improve performance slightly over common string inverters, but more importantly, the SolarEdge system offers individual panel optimisation and monitoring, which is essential for systems installed on rooftops with shading issues.
Although the initial setup time and installation cost are higher than a conventional string inverter system, the SolarEdge system provides several benefits, including improved shade tolerance, arc fault detection, simplicity in finding/replacing faulty panels, PID fault detection, and of course panel-level optimisation and monitoring. The additional safety benefits and rapid shutdown feature also reduce the risks for installers and customers in the event of damage or a severe fault.
For smaller systems with less than 7-8 modules or sites with severe shading issues, the SolarEdge system is generally not compatible. The 12-year inverter warranty and 25-year optimiser warranty are very appealing. Still, in the event of a faulty component, in some instances, the long wait times and difficulties obtaining warranty parts have resulted in prolonged system downtime.
