Al, a good quality US-designed water-cooled permanent magnet AC electric motor that can produce 15 HP continuously, and makes 30 ft lbs of torque weighs 13 lbs. A Chineasium air-cooled one, about 47 lbs. In addition to that you also need one or more batteries, a controller/inverter that turns the DC battery voltage into 3-phase AC, and a battery management to ensure that everything is operating safely. So yes, more weight. Plus the off-kart charger.
None of it is cheap initially either, roughly 2.5 - 3 times the cost for the running gear compared to a 2-stroke. And yes charging is a pain, especially in the US with our commonly available (or not at tracks) low-current 120vac system. But like anything EV, the win is in the long term operating costs. Given normal kart seasons and practices, current lithium-ion batteries should be race-worthy for about 10 years. The only wear parts are the two outer bearings in the motor, normally designed for thousands of operating hours. Electricity costs are CHEAP. To charge my 5.5kWh battery from “empty” to full at 9.8 cents/kWh (about 5kWh), with losses, is about $0.64. Commercial rate would be about 20-30% lower. Not much compared to C12 fuel, plus racing oil costs.
Where I see EV kart acceptance first is with kid karts, and then kadet. They can use the smaller, less expensive motors, need much smaller and less expensive batteries to drive them, and smaller controller/inverters.
I have nothing against hydrocarbon engines, I even work for an O&G company. There is absolutely no comparison in the energy density of hydrocarbons to today’s batteries, and I doubt there ever will be. And while I didn’t care about getting a face of oily smoke exhaust in the pits, I didn’t mind the sound and vibration that much. But after a first year of dealing with a temperamental Honda 2-stroke, and listening to some of the comments from parents with small kids about the same (smoke), I tried to push higher HP low-stressed cleaner running 4-stroke engines as a lower-maintenance step up from 206. Something in-between the 206 and 2Ts. Our karting club would hear nothing of it. So I decided if I was going to spend the money, I might as well make something as fast and fun as I possibly could, as well as low maintenance. Something I could just show up with, turn on, and go. Something that is reliable and smooth running. I’m not getting any younger (54) and I don’t really care about pure competition or points. I just want to have fun pulling Gs, and learn (a lot) about EVs at the same time.
My parts costs (no labor) for my continuous 46 Hp, 89 ft lb motor, controller/inverter, BMS, battery (1), cabling, display, etc is a little over $7k. It is designed to go up against TAG karts for a practice, qualifier, then recharge. Then the heat race, quick charge, and the main. A second/third battery would be nice to avoid having to bring a 240v generator to recharge in 45 minutes, at about $1900 extra each. But this is the “high” end, at least with today’s technology. At this point I’m waiting on the motor (delayed in production 6 months due to the wuhan flu, of course). Going crazy waiting…