The electrical box looks moisture proof. Any doubts, just use a portable GFCI.
I would relocate the spray switch to the back of the handle, to be toggled with a thumb. Having to release or alter your grip is a safety concern (even with the wheels in contact with the carpet).
One last thing; why not flare the fill opening like a funnel mouth? Hitting the small hole after reaching over the motor is just asking for a spill.
I’m a fan of
EDIC, having earned a mortgage-load of money with the little
Galaxy. If this is as trouble free and dependable, it would be worth consideration.