Save yourself the heartache of making a bad inverter decision and read this. The SMA Sunny Boy AV-40 is the modern version of the world famous SMA Sunny Boy TL once adored by many. Therefore the question must be asked, how does the new SMA Sunny Boy AV-40 compare, not just to its predecessor, but also to its modern rivals? 

Embroiled in controversy the new SMA Sunny Boy AV-40 certainly has had its critics. Die-hard SMA advocates suggest that shifting manufacturing locations from Germany to China would be the great undoing of a respected inverter manufacturing powerhouse. Others would suggest that removing the graphic display isn’t what consumers wanted. The SMA Sunny Boy AV-40 indeed was the boldest move the solar industry had seen by a manufacturer in a long time. Time to review.

What SMA inverter do you require? The SMA Sunny Boy AV-40 is the modern single phase inverter by SMA for systems rated at 3kW or above.

  • Single-phase, 1.5 – 2.5kW, SMA Sunny Boy VL-40 >
  • Single-phase, 3 – 5kW, SMA Sunny Boy AV-40. (You are here)
  • Three-phase, 5 – 12kW, SMA Sunny Tripower >
How to know if you have a single phase or 3-phase power supply? >


SMA Sunny Boy AV-40 LED Interface - Solar Review

The most controversial element of the new SMA Sunny Boy AV-40 is without a doubt the modern design. Although what appears to be initially distasteful should be viewed as a healthy progressive evolution.

As home appliances evolve to be more communicative and reliable, so must the SMA Sunny Boy AV-40 solar inverter. A common point of failure in all solar inverters is the LCD graphic display. The engineers at SMA have had some foresight on the reliability front and replaced the need for a display with a set of functional LEDs and your smart device. It’s not that bad as we now watch TV through our smartphones so not too difficult to view energy production through the same device, time to adapt.

Another big tick for the new design, The SMA Sunny Boy AV-40 has finally become more communicative adopting WiFi. Potentially one of the most significant downsides to the SMA Sunny Boy TL range – no WiFi for SMA Sunny Portal access.

Battery Design. 

Potentially one of the more versatile solar inverters for future battery integration due to SMA’s strong off-grid presence. Therefore, when the first wave of domestic lithium solar batteries rose to prominence in 2015, SMA was on the front foot with an easily integrable battery inverter in the SMA Sunny Storage. Below are 3 battery options for the SMA Sunny Boy AV-40.

Option A

Battery: LG Chem RESU & SMA Sunny Storage (AC Coupled).

Connection: Your choice of LG RESUH Solar Battery connects directly into the SMA Sunny Storage. The SMA Sunny Storage then connects directly into the same distribution board as the SMA Sunny Boy AV-40. Battery charge and discharge is communicated via the SMA Energy Meter connected to the distribution board.

Note: AC coupling increases the dwellings total inverter capacity. Specific grid connection parameters in different regions of the world limit the maximum capacity a dwelling may produce. Therefore, this method may not be for all.

Option B 

Battery: Tesla PowerWall 2 (AC Coupled).

Connection: The Tesla Powerwall 2 has an inbuilt 5kW battery inverter with 13 kWh of energy storage contained within itself. Wired directly to the same distribution board as the SMA Sunny Boy AV-40 solar inverter, the Tesla Powerwall 2 can monitor the solar production and energy supply (for charge and discharge) with CT clamps through its own communications gateway.

Note: As above in option A, AC coupling increases the dwellings total inverter capacity (example: SMA Sunny Boy AV-40 5kW + 5kW Tesla PW2 = 10kW total inverter capacity).

Option C 

Battery: SolarWatt Matrix (DC Coupled).

Connection: One string of the solar array is wired directly into the SolarWatt Matrix BMU (battery management unit). From the SolarWatt BMU, the SMA Sunny Boy AV-40 is connected via the DC input. For battery charge and discharge control, a communications gateway is installed at the distribution board.

Note: This connection method does not have an option to provide an emergency power supply in the event of a power failure.

Download the SMA Sunny Boy AV-40 datasheet here:


SMA Sunny Boy AV-40 Connection - Solar Review

Apart from the notable design alterations such as adding WiFi and removing the LCD graphic display, the SMA Sunny Boy AV-40 is rather low on exciting features. Put simply, it remains just a solar inverter with features we have come to expect as the norm in solar inverter technology. Try not to be overwhelmed with disappointment as this is a very SMA thing to do. Additional features are almost always available within the SMA suite, just in additional devices.

Other notable key features include:

  • Dual MPPTs.
  • Extra broad MPPT voltage window.
  • Optitrac Global Peak: MPPT shade management.
  • Easy installation.
  • DC isolator built in.
  • WiFi monitoring inbuilt.
  • Remote monitoring.
  • Smart Grid Ready.

Stock standard features by today’s standard, however, when presented by SMA, one can be sure these are some of the most refined and reliable.


Maximum efficiency within the SMA Sunny Boy AV-40 remains within the highest calibre. The generous operating temperature range also remains the same between -25oC to +60oC (-13oF to +140oF), and 100% humidity is a big positive. A level of noise emission is present however barely noticeable to most. For those sensitive to acute noise emission, the 25dB(A) should be factored into the selection process. A significant difference from the previous model is the weight reduction of 10 kg (22 lb). The New SMA Sunny Boy AV-40 weighs in at only 16 kg (35.3 lb). A weight which is more accommodating for load-sensitive performance requirements.

Average Inverter 95%
SMA Sunny Boy TL (old) 97%
SMA Sunny Boy AV-40 (new) 97%

Above: Solar inverter maximum efficiency.


SMA Sunny Boy AV-40 DC Isolator - Solar Review

A relatively large warranty when comparing alternative household appliances, the SMA Sunny Boy AV-40 is accompanied by a respectable 5-year part and labour warranty. A very standard warranty regarding the solar inverter manufacturing industry. The one consolation which can be drawn is the fact that the warranty is backed by the worlds longest serving solar inverter manufacturer.

Average Inverter (base)
SMA Sunny Boy AV-40 (base)
SolarEdge (base)

Above: Base manufacturer warranty on a scale of 12-years (Longest central inverter base manufacturer warranty).

Tech Insight: SMA Sunny Boy AV-40 inverters like near all standard string inverters contain electrolytic capacitors. Often the first point of failure (if installed in a protected and well-ventilated area) for many string inverters. Generally speaking, the service life for electrolytic capacitors within solar inverters is often between 5 to 10 years.


SMA Sunny Portal

SMA’s Sunny Portal was once the pinnacle of manufacturer produced solar monitoring platforms. Now, however, it appears the competition has caught up with equally insightful software. For the end user through an SMA Sunny Boy AV-40 connected to the SMA Sunny Portal is a must.

  • Basic live energy production.
  • In-Depth production analysis.
  • Historical data logging.
  • System savings in monetary value.
  • CO2 savings.
  • Programmable automatic reporting features.
  • Advanced email warning and notification system (including energy fluctuations, system dropouts, earth fault alarms).
  • Assign alternative users and administrators.

Tip: Go one step further with SMA Sunny Portal and enjoy module level monitoring with Tigo. Additional devices required.

Sunny Portal remains quite buggy when integrating additional devices such as the SMA Energy Meter. A redesign of the monitoring dashboards as optimised displays would be as welcome as a refreshing spring clean.   

Mobile Applications : The SMA Sunny portals mobile application is quite limited in detail providing necessary energy information only when compared to a browser-based login. As with all inverter manufacturer supplied mobile applications this level of insight is underwhelming.


SMA Sunny Boy AV-40 Logo - Solar Review

The SMA Sunny Boy AV-40 is not the cheapest inverter you’ll find, but it’s also not the most expensive due to a shift in manufacturing origins. A good compromise for a product which remains held to rigorous German quality standard.

As a gauge, SMA Sunny Boy AV-40 5kW inverters are available online from USD 1250, AUD 1700, EURO 1050 excluding taxes, shipping and installation.

Source – Google.


The SMA Sunny Boy AV-40 could have been much more given where solar technology is heading. Although very future ready, the old SMA ways of adding additional device after device to accommodate the future are becoming distasteful. None-the-less the SMA Sunny Boy AV-40 is an excellent solar inverter option by a trusted inverter manufacturer.


View the SMA Sunny Boy AV-40 score below. Got questions? Alternatively, have a different perspective? Have your say in the comments below.


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