outdoorsnz:
I have a flat 30 odd liter spray tank. And connected to that is a 12V pressure pump running off a 12V jump starter. Have quite a long strong rubber hose and spray wand. Saves lots of time and means you can make up a bulk solution to do the whole house. I just wheel it around on a flat wheel barrow.
You could also try those rapid hose adapters that 30 seconds etc are heavily promoting now. But I tried than once and thought it was a big rip off because if you have the water pressure to high, it is all gone in 30 seconds!
Yeah, not worth getting something like that for an annual wash. Yeah the hose connected ones probably don't last as long as they should, but if I need two of the hose connected things once a year @ $30 each instead one that's cheaper than buying another thing that's a bit like a pressure washer and means I don't have more stuff cluttering up the shed.