Use Steca power inverter without special piggyback controller

paul8f

Got a cheap modular inverter for use with solar panels (500w Steca StecaGrid 500-M4). I want to use this grid-tied inverter off-grid. Trouble is I don't have the special controller for it. The inverter does not output anything without the data connection between the inverter and this missing controller.

The data bus is a 12 pin "Steca data connector" (6 DIL connector). I don't need any of the special functions. I just need ON/OFF control. I'm guessing the inverter is waiting for a certain pin to be pulled low or a CLK signal to appear before enabling the control circuit. Can't find any circuit diagrams online. Anything I could do to get the inverter to switch on?

...just to add... there's a small chance that the inverter isn't enabling due to a 50Hz signal not being detected on the looped mains connector. (but I'm guessing it's more to do with the data bus).

I'll take any advice.

How are you going to use a grid tie inverter off grid?
It won't output until it sees a grid.

Have you also got an off-grid inverter to manage AC coupling?
SMA Sunny Island and Trace SW4548e can do this but it's a very niche market and an expensive route.

Doesn't make any sense going DC at the solar panels -> AC at the inverter -> DC back to batteries -> AC to loads. Lossy.

If you have >100's of meters between your installations, AC turbines and daytime loads it works out ok, cheaper on cable.

gctest50

paul8f wrote: »

Got a cheap modular inverter for use with solar panels (500w Steca StecaGrid 500-M4). I want to use this grid-tied inverter off-grid. Trouble is I don't have the special controller for it. The inverter does not output anything without the data connection between the inverter and this missing controller.

The data bus is a 12 pin "Steca data connector" (6 DIL connector). I don't need any of the special functions. I just need ON/OFF control. I'm guessing the inverter is waiting for a certain pin to be pulled low or a CLK signal to appear before enabling the control circuit. Can't find any circuit diagrams online. Anything I could do to get the inverter to switch on?

...just to add... there's a small chance that the inverter isn't enabling due to a 50Hz signal not being detected on the looped mains connector. (but I'm guessing it's more to do with the data bus).

I'll take any advice.

don't know if you have this / is it much use ?

http://bt2.steca.de/index.php?StecaGrid_Service_Inverter_Selftest_Protocol_en

The StecaGrid Inverter Selftest Protocol software allows professional fault analysis of StecaGrid inverters. It is used for reading the self-test results from various different StecaGrid inverters.
The software is installed on a PC/notebook, which is then connected to the inverter using a special adapter cable.