Dan

The motor is a D&D model ES-33, and you know the controller. The kart weighs right around 500 lbs. (227 kg), and of that, about 300 lbs (136 kg) is battery weight. I mounted the batteries in the “saddle bag” configuration for stability, which works well. The Optima Yellow tops are not really “automotive grade” batteries, rather, they’re deep cycle units. I tried automotive starting batteries on the previous kart, and the results were less run time and ruined batteries.
Center of gravity is about where the driver’s belt buckle would be. I normally drive the kart like I’m trying to break it – that is to say I drive it hard. With fresh and charged batteries, I get about 1 hour of run time. I monitor the battery voltages, current, and charge with a PakTraker module in the center of the steering wheel. I don’t have a balancing system, so I charge with 6 individual chargers. I’m looking to change that.
I’ve gotten a lot of grief about lack of safety equipment, but despite appearances, I’m pretty careful about where, when, and how I drive the kart. I realize that the driver’s head is at about the level of a car bumper.
Finally, *normal* top speed is closer to 50mph (80kph). The difference is the rear tires. The larger “retro look” rear tires were used to set my personal speed record.