Rusty Spanner

Been through this myself on the narrowboat—went through three different setups before landing on something sensible.

The thing that'll make or break a 400W system isn't the wattage itself—it's your actual usage pattern and how honest you are about winter performance.

@ExFirefighter42 and @NickHughes have nailed it—constraints absolutely shape what "off-grid" looks like in practice.

@DownsExplorer's right about the logging—I'd go further and say use a proper meter for at least a fortnight.