Breaker
Picture of the circuit breaker on the right, and the Curtis Controller on the left. The lightbulb acts as a precharge resistor. This prevents too much current from hitting the capacitors in the controller.
I am currently using a 250 Amp breaker. I plan on upgrading it to higher amperage because the breaker trips a lot. Currently I drive 18 miles one way to school. During that drive, 90% of the road speed limits are 45 mph or less. However, the breaker will trip at speeds as high as 35 mph if I overaccelerate. To counter this, I accelerate slowly and can get to speeds of 45 mph in cold weather. During the summer I got to 55 mph. I consider this my training exercise so that I won't run out of battery power, and get accustomed to driving appropriately. It takes a different driving style, since you are so concerned about saving battery power on each trip. I plan to upgrade the breaker.