What is the best setup 8xl and warrior 9920

[Serum]

I am sorry, but 12 cells can do 1200 watts and 18 cells can do 1800 watts. (that's no 100% boost, but 50)

And if you need 1200 watts on 12 volts, it is 100A and on 18volts that is 66.67A, (P=U.I) and like i said, if you use the same power, runtime WILL be larger, not smaller. Adding cells gives you more energy, so runtime will increase. I know this law of Ohm, but in this, you forget a few things, the cells can deliver a maxximum amount of power each. this will not increase if you add an extra cell.