I could run 4 36 volt per Mars but it is double the price.. Wish they were cheaper for the 36 voltThere is no meaningful difference in output between the 36 and 72 volt cobs. In fact, amateur light builders are better off sticking with the 36v just for safety reasons, the resistance barrier of your skin is 40 volts, only .100 amps at 72V has the pontential to kill you.