I used to drive an electric forklift; we had two at a warehouse where I worked. Under typical heavy use we'd need to swap out the batteries in each forklift every two hours or so. That said, it was one heavy MF of a battery. Better to have two people changing one together, although I could do it by myself.

Not sure how practical that would be for a heavier vehicle, with a typically longer desired battery life (range) and consequently (in total) much heavier batteries.

Charging each forklift battery took eight hours or more, so we couldn't wait for them. Swapping one only took five minutes. We had to keep a number of spare batteries constantly charging on an array of rechargers just to keep both our vehicles constantly working all day long (ten hours). We had five for each. Yep... we had ten rechargers and twelve batteries total for our two forklifts.

Sure, we could have used four smaller batteries instead of one, but then we'd need four rechargers in place of each one. That would've been forty chargers required. If smaller units sped up the charging time by a factor of four, then we'd still need the original ten chargers each.

How that would play out with tens of thousands of cars, and even more thousands of battery units constantly sitting in more thousands of rechargers...? Not well, I think.