Minimum 24v and 70 lb. 36v even better and batteries will last much longer the higher the voltage.
Expensive up front but will pay for itself in the long run. I think 55lb is max on 12v system but
A 24v on half power will out pull a 12v on full power even with they were same thrust rating and will be less drain on the battery.
From Genesis: "And God promised men that good and obedient wives would be found in all corners of the earth."
Then He made the earth round...and He laughed and laughed and laughed!