They also hate being shorted out. There are whole car brands, both gas and electric, with a manufacturing error that rivals the hoverboard in spontaneous combustion, completely unprovoked. Sometimes the battery just says "I give up" without rhyme or reason. And an average car fire soars ten meters into the sky at its peak, it's not something you could just "put out" if caught in time. If it's in a driveway, you typically just end up with a crisp car, but in a garage, it's like playing Russian roulette with your whole house. Would not recommend.