The 1,500 watt toater is @ 120 volts.
P=I*V 1,500/120= 12.5 amps
P=I^2*R R=1,500/12.5^2 = 9.6 ohms
P=V^2/R = 48V^2/9.6 = 240 watts , Not 1,500 watts if my math is correct. I am pretty rusty these days.
To your other comment: I do have an enormous battery. I rode my fat e bike today 94.5 miles and used 1,364 watt hours. Average speed 14.5 mph. I can put that back in the battery in under two hours. I have a 52 volt 49 amp hour bank.