For those of you new to using a Fantom. It runs the motor at 5 volts. Due to variance in their electronics very little correlation can be drawn comparing numbers between different dynos. When these were released it was recommended that you have a huge amp source at 12 volts. That is why I went with a garden tractor battery. Brushed motors could have startup draws of over 120 amps @ 5 V. And when testing multiple setups and multiple motors you needed a big power supply or a reasonable lead acid battery. Brushless don't have as big a demand but if you want to do 10+ pulls I would still want that big amp reservoir. I also equiped mine with Deans plugs just to avoid a backwards hook-up. Nothing like replacing that big cap inside after a poof.