We’ve found many SMA inverters installed incorrectly which not only voids the warranty on the units but also creates a potential failure point inside the inverter.
The above picture shows the AC connection inside an SMA Sunny Boy SB1100. As you can see, the push on terminal is burnt due to the fact that is was oversized and didn’t create a strong and secure connection. The result was, it began to arc until it reached the point of melting the terminal on the printed circuit board and disconnecting altogether.
The green light on the inverter was flashing as shown in the video below because it was trying to connect to the grid but was unable to. In this instance (and many others) the installer disconnected and removed the supplied AC wiring and plug connection and hard wired the AC wiring from the solar supply main switch to the AC connection in the inverter. This did two things… (1) It void the warranty on the inverter immediately. Unbeknownst to the customer, they had a brand new inverter with no warranty because of the way it was wired. (2) The “push on” connectors the installer used were over sized meaning they weren’t tight enough on the pins on the printed circuit board and consequently began to arc under load. This arcing caused burning until they reached the point of disintegration and disconnection.
We were able to repair the connection with a solder joint on what remained of the pin on the printed circuit board. It was either this, or the customer was up for a new inverter which they obviously decided not to do. The end result was a working inverter for a small fee. Thankfully, this inverter is still operating years after the repair was made. Thankfully no other issues have occurred with the inverter as it had no warranty from day one.