Thanks for that. I didn't realize the manual was available online. I'm having trouble downloading it just at the moment, but I'll get there. I remember that it says small portable type generators MUST NOT be used, but I figured it was simply because of the irregular cycle caused by a single cylinder engine not being recognized by the inverter input side. I didn't realize damage could be done. That's why I thought an inverter generator would be ok, because it will have a perfect cycle. The inverter isn't connected to the house wiring system, just to a backup consisting of sockets for fridge and freezer. Lights and electronics etc are 12v where possible for simplicity.