For my DIY powerwall project I can buy a hardly used Quattro 48/5000/70. Sadly the seller cannot show the device in a working setup, The story is that the new Quattro was changed some years ago for another system/brand. After sitting on a shelf for some years he now whats to sell the Quattro.
Anyone tips on testing a Quattro that is not in a working setup? Or is it a big gamble?