Too Heavy
One of the main downsides of having a big battery pack underneath your car is the additional weight. While most modern vehicles are heavy due to all the extra safety and comfort options, electric vehicles are the heaviest champions. On smaller models like the Kia Soul EV, the electric batteries add around 450 extra pounds of weight (via Click on Detroit).
However, on some of the high-end models like the Tesla Model X, the battery pack weighs in at over 1,000 pounds. Also, the car itself weighs over 2.3 tons. Heavy vehicles mean more tire wear, more energy consumption, and maintenance too.