[vvbull]

The problem isn't the battery catching fire, it's that you no longer have a circuit breaker between your appliances and the generator. Meaning you could, especially if you have several batteries, push load through wires in the wall in excess of what is rated for.

[xbmcuser]

it is the same as the balcony solar though so what is the difference the batteries would be doing the same exact thing?

[gambiting]

Maybe you don't know this, but in the UK every single appliance has its own individual fuse right inside the plug.

[angry_octet]

You can have multiple loads and sources that are in-spec but the wiring between them is overloaded.