Re: turning off the battery - I thought most of these dolphin case batteries came with a BMS that would auto power down if it wasn't used for 10 minutes or so - at least mine has.
Nice looking fatbike though - good price for what you get. I know there seems to be issues getting it here in Norway because of battery shipping but it would be worth getting it shipped without the battery (assuming there was a reduction in initial cost) as it's simple enough to get a battery here to fit.
I do like the look of the fenders. Interesting comment on the loudness of the motor - I find mine to be quite quiet, the hum of the tires competes above 13mph. I also find it quieter than my previous BH Easy Motion neo xtrem motor was as well.